the species question - colorado parks and wildlife · 2015-02-06 · september 1, 2006 dear...

The Species Question

Applying TaxonomyTo Wildlife

Research AndManagement


Applying TaxonomyTo Wildlife

Research AndManagement

September 1, 2006

Dear Educator,

Colorado has long been committed to the conservation of all wildlife species, whether hunted, orfished, or viewed. One of the nation’s great wildlife restoration success stories—the AmericanPeregrine Falcon—had its beginnings here in the early 1970’s. A Colorado biologist rappelledover cliffs more than 500 feet high, dangled from a thin rope and dodged swooping Peregrines toretrieve their DDT-thinned eggs. He tucked them into his vest and made all-night drives acrossthe state for artificial incubation and hatching. Other successes, such as the restoration andrecovery of prairie grouse, lynx, river otter and a number of native fishes, also have their roots inthe efforts of Colorado Division of Wildlife professionals.

Science-based management decisions are essential to securing species at risk, as well asconserving all the state’s wildlife species. The numbers of scientific disciplines that influence andinform wildlife management are staggering. Advances in taxonomy and molecular biology, inparticular, have affected how biologists think about and identify species and subspecies. We inviteyou and your students to explore new developments in the frontiers of science with us as weharness innovative technologies and ideas and use them to maintain healthy, diverse and abundantwildlife.

Sincerely,

Bruce L. McCloskeyDirector

Content Advisors and Reviewers:

Lisa Evans, Northeast RegionEducation Coordinator, DOW

Leigh Gillette, Southwest RegionEducation Coordinator, DOW

Linda Groat, Southeast Region RuralEducation Specialist, DOW

Renee Herring, Wildlife WatchCoordinator, DOW

Stan Johnson, Northwest RegionEducation Coordinator, DOW

Debbie Lerch-Cushman, Metro DenverEducation Coordinator, DOW

Steve Lucero, Southeast RegionEducation Coordinator, DOW

Tabbi Kinion, Project WILDCoordinator, DOW

Ken Morgan, Private Lands HabitatSpecialist, DOW

Jeff Rucks, Head of Education, DOW

Gary Skiba, Senior WildlifeConservation Biologist Supervisor,Southwest Region, DOW

Graphic Design:

Darren Eurich, State of ColoradoIntegrated Document Solutions (IDS)

Illustrations:

Helen Zane Jensen, Sage Grouse andSage Grouse anatomy illustrations onpages 22 and 24

Marjorie Leggitt, All Other Illustrations

Classroom Observations and EducatorInterviews:

Wendy Hanophy, DOW

James Phillips

Administrative Assistance:

Emily Wiseman

Project Coordinator and Editor:

Wendy Hanophy, DOW

Writers:

Wendy Hanophy, DOW

Larry Ann Ott, Retired Educator,Adams County School District 12,Colorado

Copy Editor:

Tim Pollard, Colorado Department ofNatural Resources

Printing:

State of Colorado IntegratedDocument Solutions (IDS) PrintOperations

©Copyright 2006 by Colorado Division of Wildlife. All rightsreserved. Permission granted to reproduce handouts forclassroom use. All illustrations are copyright by the artistsand may not be reproduced or transmitted in any form orby any means, electronic or mechanical, or by any infor-mation storage or retrieval system, without permission inwriting. For permissions and other rights under thiscopyright, please contact Colorado Division of Wildlife,6060 Broadway, Denver, CO 80216, Attn: Wendy Hanophy.

Acknowledgments

Funding for this project was provided by US Fish & Wildlife Service WildlifeConservation and Restoration Program Grant No. R-11-1, Great Outdoors ColoradoTrust Fund (GOCO), and the sportsmen of Colorado.

The Colorado Division of Wildlife gratefully acknowledges the following individuals:

For content advice and critical review:

Dr. David M. Armstrong, University of Coloradoat Boulder, Department of Ecology andEvolutionary Biology

For assistance in developing the field test:

Nicole Knapp, Science Educator, BSCS

Anne Tweed, Senior Science Consultant, McREL(Mid-continent Research for Education andLearning)

Pam Van Scotter, Director, BSCS (BiologicalSciences Curriculum Study) Center forCurriculum Development

Field-test Educators:

Shelley Harwell, Heritage High School, Littleton, CO

Field-test Educators (cont.):

Jeff Keidel, Buena Vista High School, Buena Vista, CO

Matt Landis, North Park High School, Walden,CO

Robert Lancaster, Walsh High School, Walsh, CO

Mark Little, Broomfield High School, Broomfield,CO

Rick Moeller, Mountain View High School, Loveland, CO

Lyn Neve, Swink High School, Swink, CO

Dorothy Schnabel, Granada Undivided HighSchool, Granada, CO

Jill Smith, McClave High School, McClave, CO

Debbie Yeager, Moffat County High School, Craig, CO

The Species Question Applying Taxonomy To Wildlife Research And Management

Module Overview . . . . . . . . . . . . . . 1

Lesson 1: The Species Question Educator’s Overview. . . . . . . . . . . . 6

The Species Question . . . . . . . . . 10

Lesson 2: Birds Of A Feather Educator’s Overview. . . . . . . . . . . 16

Birds Of A Feather . . . . . . . . . . . . 20

A Closer Look . . . . . . . . . . . . . . . . 21

Hidden In Plain View. . . . . . . . . . . 26

Lesson 3: Taxonomy Through The Ages

Educator’s Overview. . . . . . . . . . . 28

Taxonomy Through The Ages. . . . 41

Lesson 4: Understanding UngulatePhylogeny


Understanding Ungulate Phylogeny . . . . . . . . . . . . . . . . . . . . . . . . . . 56

Table Of ContentsTable Of Contents

Lesson 5: The Pocket GopherCladogram Conundrum


Pocket Gophers Of Colorado. . . . 68

Characters Of Colorado Pocket Gophers . . . . . . . . . . . . . . . . . . . 69

The Pocket Gopher Cladogram Conundrum . . . . . . . . . . . . . . . . 70

Lesson 6: Déjà Vu Educator’s Overview. . . . . . . . . . . 80

Déjà Vu . . . . . . . . . . . . . . . . . . . . . 84

Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . 95

Table Of ContentsTable Of Contents

1T h e S p e c i e s Q u e s t i o n

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Taxonomy—It’s Not Just for Geeks Anymore!

Taxonomy is the science-based hierar-chical classification of the world’s species.Over the centuries, taxonomy has been usedto organize, interpret, and understand thediversity of life on Earth.

As a science, taxonomy had traditionallybeen viewed as an obscure disciplineinvolving brainy professors and highbrowscience know-it-alls who would memorize andinterpret thousands of Latin species names.Few paid attention to advances in the field orto the many scathing disputes between taxon-omists. A decision to place an organism in thegenus Spea rather than Scaphiopus would notmake the front page of the newspaper, oreven the back page for that matter. Educatorssuch as yourself would cruise through thetaxonomy section of the textbook as quicklyas possible, and move on to more vital topics.In a word, taxonomy was BORING.

Public and academic indifference totaxonomy was lost forever when precisetaxonomic recognition of species andsubspecies came to be the basis forprotection under the Endangered Species Act(ESA). Signed into law by President RichardNixon in 1973, the law is considered one ofthe most stringent environmental protectiondocuments ever enacted. The penalties arestiff. Anyone found to take, harass, harm,pursue, hunt, shoot, wound, kill, trap, capture,or collect a listed species could receive jailterms and large fines. The ESA also impactsland use decisions, which can in turn impactindividuals, families, communities andeconomies in unforeseen ways. In addition,

each state’s wildlife management options arerestricted by a species status. Some speciesmanagement falls under the purview of theFederal government.

Now that taxonomy can literally hitsomebody “where they live,” the ideas andmethods of delineating species have becomeeveryone’s business. While no conscientiousperson would seek to propel a fellow creatureinto the long night of extinction, few wouldwant to limit what they could do with theirproperty or their life without good evidencethat it really mattered to a species’ survival.

It turns out that sometimes hard evidenceis slow in coming. Many of the ideasscientists hold about species, including theconcept of species itself, are undergoingrevision. With advances in molecular biology,we find that some animals that look alike arein no way related. Contrarily, some that lookdifferent have nearly identical genetics! Forstudents (or anyone, for that matter) used toclean, clear-cut answers, this module ontaxonomy and systematics might be“annoying.” Each concept of species has itsdeficiencies, so modern-day biologists rely onlegal definitions and agreed uponconventions. They employ techniques ofcladistics and evolutionary systematics todetermine both the relatedness of organismsand their potential for a unique evolutionaryfuture. Once viewed as a “stagnant”science—taxonomy is exciting and chal-lenging. As you and your students join us inour discoveries, our questions, and ourarguments, you will develop a clearer under-standing of the nature of scientific knowledgeand the scientific process, the humandimension of science, and the value of peerreview.

Module Overview

The Species QuestionApplying Taxonomy To Wildlife Research And Management

2 T h e S p e c i e s Q u e s t i o n

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What is This?This six-lesson module, designed for

almost two weeks of classroom instruction,begins with basic high school level taxonomyand classification, and then introduces thelarger field of systematics. The module isdesigned to supplement or replace theactivities found in most high school biologytextbooks that address these topics. It is thesecond module developed by the DOW toaddress the specific learning objectives ofhigh school students. Materials are inquirybased, develop critical thinking skills, supplyevidence to support each concept, andinclude real data from recent researchprojects. The last two lessons also emphasizethe ethical tradition of scientists; the value ofpeer review, truthful reporting about methodsand outcomes of investigations, and makingpublic the results of scientific work.

Using The Species Question:Applying Taxonomy To WildlifeResearch And Management in YourClassroom

The lessons in this module are designed tobe taught in sequence. For each activity, thestudents take on the role of a wildlifebiologist, receive an introduction to theproblem and to their task, and choose andanalyze relevant information.

There are DOW Education Coordinatorsthroughout the state that may be able toprovide additional materials, such as sagegrouse wings, to supplement these lessons orto provide resources on other biology topics.Feel free to contact your EducationCoordinator at any time—they would love tohear from you:

Leigh Gillette, Education Coordinator, SW Region 415 Turner Drive Durango, CO 81303 970-375-6709

Stan Johnson, Education Coordinator, NW Region 711 Independent Avenue Grand Junction, CO 81505 970-255-6191

Linda Groat, Rural Education Specialist SE Region 2500 S. Main Lamar, CO 81502 719-336-6608

Steve Lucero, Education Coordinator, SE Region 4255 Sinton Road Colorado Springs, CO 80907 719-227-5203

Lisa Evans, Education Coordinator, NE Region 317 W. Prospect Fort Collins, CO 80526 970-472-4343

Debbie Lerch-Cushman, EducationCoordinator, Denver Metro Area 6060 Broadway Denver, CO 80216 303-291-7328

Correlation to the Colorado ModelContent Standards

The Species Question: Applying TaxonomyTo Wildlife Research And Managementsupports teachers in their efforts to providethe knowledge and skills specified in theColorado Model Content Standards and thecorresponding grade level assessmentframeworks.


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Science1: Students understand the processes of scientific X X X Xinvestigation and design. They conduct, communicate about and evaluate such investigations.

3.1: Students know and understand the characteristics X X X X X Xof living things, the diversity of life, and how living things interact with each other and with their environment.

3.3: Students know and understand how the human X X X Xbody functions, factors that influence its structures and functions, and how these structures and functions compare with those of other organisms.

5: Students know and understand interrelations among X X X Xscience, technology, and human activity and how they can affect the world.

6: Students understand that science involves a X X X X X Xparticular way of knowing and understand commonconnections among scientific disciplines.

Lesson 6: Déjà Vu

COLORADO MODEL CONTENT STANDARDSLesson 3: TaxonomyThrough The Ages

Lesson 4: Understanding

Ungulate Phylogeny

Lesson 5: The Pocket

Gopher CladogramConundrum

Lesson 1: The Species

Question

Lesson 2: Birds Of A

Feather

Reading and Writing1: Students read and understand a variety of materials. X X X X X X

2: Students write and speak for a variety of purposes X X Xand audiences.

3: Students write and speak using conventional X X X X X Xgrammar, usage, sentence structure, punctuation,capitalization, and spelling.

4: Students apply thinking skills to their reading, X X X X X Xwriting, speaking, listening, and viewing.

5: Students read to locate, select, and make use of X X Xrelevant information from a variety of media, reference,and technological sources.

Lesson 6: Déjà Vu



Ungulate Phylogeny




Question


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Geography2: Students know the physical and human Xcharacteristics of places, and use this knowledge to define and study regions and their patterns of change.

3: Students understand how physical processes shape X X XEarth’s surface patterns and systems.

5: Students understand the effects of X X Xinteractions between human and physical systems and the changes in meaning, use and importance of resources.

6: Students apply knowledge of people, places, and X X X Xenvironments to understand the past and present and to plan for the future.

Lesson 6: Déjà Vu



Ungulate Phylogeny




Question


Feather

Mathematics1: Students develop number sense and use numbers Xand number relationships in problem-solving situations and communicate the reasoning used in solving theseproblems.

3: Students use data collections and analysis, statistics, Xand probability in problem-solving situations and communicate the reasoning used in solving these problems.

Lesson 6: Déjà Vu



Ungulate Phylogeny




Question


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Learning ObjectivesAfter completing this activity, students will be able to:

• Identify the strengths andweaknesses of the speciesdefinition used in theirtextbook.

• Compare various speciesconcepts and make a note ofthe variety of characteristics(physical, molecular,geographical, ecological, andso on) that biologists use toidentify organisms.

• Make a case for thenecessity of a legal definitionof species for wildlifemanagers.

BackgroundIn biology, a species is the

basic unit of biodiversity. It oftencorresponds to the way peopleidentify different kinds oforganisms. We “name” livingthings using this concept, eitherwith standard scientific binomial

(or trinomial) nomenclature or ineveryday vernacular. Somethingis a dog, a cat, or a turtle.

Traditionally, people relied on observations of anatomicaldifferences and breedingbehavior to distinguish species.Before Darwin, species werethought to represent independentacts of creation, and wereconsidered immutable. A centuryand a half later, with the arrival of evolution theory, the discoveryof genes and the advances inmicrobiological research—including DNA analysis—a greatdeal of knowledge about thedifferences and similaritiesbetween organisms has becomeavailable. Species evolve—theychange over time. Speciesconcepts also evolve; and thescientific community seems tohave more disagreement aboutwhat constitutes a species nowthan ever before.

It may come as a shock toyour students to discover thatthere is no commonly accepteddefinition of what a species is. While the class textbookprobably contains some version

Educator’s Overview


SummaryStudents read an article, then discuss and evaluate the

strengths and weaknesses of several species concepts. Theythen discuss the consequences of conflicting definitions on a state wildlife agency’s ability to conserve species and theecosystems upon which they depend.

Duration One 45-minute class period

VocabularyBiodiversity

Clones

Distinct PopulationSegment (DPS)

Endangered

Hybrid

Morphological

Niche

Reproductiveisolation

Species Concepts • Biological

species concept• Ecological

species concept• Isolation species

concept• Morphological

species concept

Subspecies

Threatened

Wildlife

Wildlifemanagement

Lesson 1


Lesson 1: The Species Question

of the biological species conceptthat has predominated secondarytexts over the past 60 years, thatdefinition has some seriousdrawbacks. The textbook defi-nition provides a starting placefor students to study the varietyof life, but it is important foreducators to emphasize that it issimply one of many speciesconcepts. Definitions are a lotlike hypotheses—scientists mustcontinually test their usefulnessin the light of new information.

For wildlife professionals andother scientists tasked withpreserving the variety of life onearth, the species question isimportant. Some working defi-nition of species is needed toframe and implement biologicallaws—such as the EndangeredSpecies Act.

Teaching Strategies1. Thoroughly read thestudent materials for TheSpecies Question.

2. Give each student the firstreading packet, The SpeciesQuestion.

3. After giving studentssufficient time to read thepacket, discuss the manyspecies concepts as a class.What are some of the reasonsthat there is little agreement onspecies concepts? There arehuge differences among thekinds of organisms; organismshave different kinds of repro-duction (sexual or asexual),some organisms look similarand live in the same envi-

ronment but do not interbreed,while others look very differentand live in radically differentenvironments yet caninterbreed and produce fertileoffspring, and so on.

4. Discuss the various speciesconcepts in terms of thescientific process. Why is thedefinition of species beingdisputed? New informationabout genetics and evolutionhas caused scientists toreevaluate their ideas aboutliving organisms.

5. Why is a legal definition ofspecies needed? Wildlifemanagers and others mustmake decisions and takeactions to maintain healthypopulations of organisms andtheir habitats. In order to avoidconfusion and possibly courtbattles, they need to agree onwhat populations needprotection.

AssessmentStudents’ comparison of

their textbooks’ species defi-nition with the characteristicsused by wildlife biologists todetermine species serves asan assessment for this activity.

Materials andPreparation

• Student ReadingPages for

The SpeciesQuestion—one

photocopy per student

• Access to biologytextbook and

internet


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Extensions• Students could read and evaluate the

Policy Regarding the Recognition ofDistinct Vertebrate Population under theEndangered Species Act. The documentcan be found at:

http://www.fws.gov/endangered/federalregister/1996/p960207c.pdf.

There was considerable national debateduring the drafting and public commentperiod of this document. The recommen-dations and criticisms are summarizedand addressed by the Department of theInterior. After students read thesearguments, do they agree or disagreewith the responses?

Key1. How many different definitions ofspecies did you find? Answer varies

2. List at least three other speciesconcepts that you found: Answers willvary, but some of the other speciesconcepts are Recognition, Evolutionary,Phylogenetic, Diagnosability, Cohesion,Genealogical, Cladistic, and Pluralistic.

3. What is your biology textbook’s defi-nition of species? Answer varies

4. Does the textbook definition share anyof the characteristics used to determine adistinct population segment? If so, whichones? Answer varies

5. Why is a legal definition of speciesnecessary? State and federal lawsrequire that wildlife agencies protectwildlife species and biodiversity. Thereneeds to be a clear and consistent wayto determine whether an organism is aspecies so that the organism can bemanaged appropriately.



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The Colorado Division of Wildlife(DOW) is the state agency responsible forprotecting and managing wildlife andhabitat, and providing wildlife relatedrecreation. The DOW employs trained biol-ogists and other specialists to “manage”wildlife—to use scientific knowledge tomaintain healthy populations of wildlifeand its habitat and preserve biodiversity.Wildlife includes all non-domesticmammals, birds, fish, amphibians, reptiles,mollusks, and crustaceans that occurwithin the boundaries of the state.Biodiversity is short for biologicaldiversity. It includes the variety of species,the genetic differences within species, andthe variety of ecosystems in the state.

Biologists at the DOW also abide by federal wildlife laws. One of the most important of these laws is theEndangered Species Act (ESA) of 1973that protects plants and animals frombecoming extinct in this country. Underthe ESA, species may be listed as either“endangered” or “threatened.”Endangered means a species is in dangerof extinction throughout all or a significantportion of its range. Threatened means aspecies is likely to become endangeredwithin the near future throughout all or asignificant portion of its range.

What is a Species?Before a species can be managed and

protected, it must be identified.Unfortunately, what might seem to be thesimplest task in biology can be one of themost baffling. What is a species? Youwould think that the question would have

Student Pages


“It is the policy of the state of Colorado that the wildlife and their envi-ronment are to be protected, preserved, enhanced and managed for the use,benefit, and enjoyment of the people of this state and its visitors.”

—Colorado Revised Statutes 33-1-101 (1)

Kingfisher



been answered ages ago, but it crops uprepeatedly in many different circum-stances. As experts try to create defi-nitions of species to apply to the varioustypes organisms that they are studying,each seems to have its shortcomings.

One of the oldest methods for iden-tifying species is to group organisms thatare similar to each other in appearanceand behavior. This is the morphologicalor phenetic species concept, whereorganisms with similar physical traits arelumped together as species. Using thisdefinition, Chihuahuas, Saint Bernards,Pugs, and German Shepherds could all bedifferent species. So could Shetland

ponies, Clydesdales andThoroughbreds.

Then there is the ecological speciesconcept, which defines a species by itsniche or ecological role—the set ofresources it consumes and habitats itoccupies. This definition might work wellfor an organism such as an Abert’ssquirrel, which only lives in ponderosapine forests and only eats ponderosa pinenuts. It is a bit more challenging to applyto a coyote, which lives in nearly everypart of the state and eats virtuallyanything. Would a coyote living in aspruce/fir forest eating red squirrels be adifferent species than a coyote living in thegrasslands eating rabbits?

Dog Gone It!One of the more widely accepted defi-

nitions—and possibly the one found inyour biology textbook—says a species is agroup of organisms that are geneticallysimilar enough to breed and produceviable and fertile offspring. This biologicalspecies concept seems simple enough,and seems to incorporate both themorphological and ecological speciesconcepts. After all, if organisms are able tobreed, they must have similar character-istics, behavior and ecology.

Abert’sSquirrel

Coyote


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Looking at different canines, we findthat even this definition has its problems.For example, pugs do not look likewolves, coyotes, jackals, or dingos. Pugsoften occupy the plush chair in the livingroom, while wolves are adapted to forests,jackals to dry grasslands in Africa and soon. Nevertheless, given the opportunity,pugs can interbreed with all these species

and produce fertile offspring. Given that allthe wild canines mentioned can potentiallyinterbreed with domestic dogs like thepug, are they all one species?

It gets even more complicated.Coyotes and wolves can and dointerbreed in areas where their rangesoverlap, but only female coyotes matewith male wolves and their offspring onlybreed with wolves. What prevents malecoyotes from mating with female wolves?Moreover, in Africa, where there areseveral different types of jackal sharing thesame habitat, they completely ignore eachother. If mated under artificial conditions,these jackals can produce fertile offspring.

Wolf

Pug



Cats Too!This problem is not just limited to

canines. Lions and tigers normally do notshare the same habitat. Lions live on theAfrican savannah (grasslands) and tigersinhabit the jungles of Asia. However, whenthey are placed together in zoos, theycourt, mate, and produce fertile tigons andligers.

One noted zoologist attempted toaddress this issue by changing thedefinition of a species slightly.

His isolation species concept defined aspecies as groups of interbreeding naturalpopulations that are reproductivelyisolated from other such groups.Reproductive isolation means that apopulation of animals cannot mate withanother population of animals due tosome barrier or factor such as:

• Differences in behavior

• Physical or geographical barriers

• Incompatible mating structures

Because reproductive isolation is not always complete, someanimals—such as the canines andfelines already mentioned—canproduce fertile offspring when in

contact with one another.Others, such as the horseand the donkey, canproduce a healthyoffspring—a mule—thatis infertile. As anotherworking definition, thefertile or infertileoffspring of normallyisolated populationsare called hybrids.

Tiger

Lion


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Just for LaughsSo far, all of these definitions of

species have been for organisms thatreproduce sexually—where there are twoparents, male and female. What definitioncould be used for organisms that do notneed mates to reproduce? Most of thesespecies’ offspring are exact copies ofthemselves—clones. For the most part,wildlife biologists do not need to worry somuch about these types of organisms,since most are bacteria, fungi, plants orsome other living thing that does notcount as “wildlife” under the law. However,some “female” reptiles, amphibians, andfish can reproduce without a mate, orbecome “male” when need be.

Many collegebiology textbooksmay list seven oreight definitions of“species!” Just for

laughs, type “define species” or “speciesconcepts” into an internet search enginesuch as Google, MSN Search, Yahoo, orwhichever search service you haveavailable. How many different definitionsof species did you find? ______________List at least three other species conceptsthat you found:____________________________________________________________________________________________________________________________________________________________________________________________________________________________________

Let’s Get Practical!It is really a challenge to come up with

a definition for a species that works inevery case. Because laws to protectwildlife and biodiversity depend ondefining which organisms are species, allthe conflicting definitions posed a problemfor state and federal wildlife agencies. Alegal definition of species was needed.

The Endangered Species Act wasrevised in 1978 to define the term"species" to include “any subspecies offish or wildlife or plants, and any distinctpopulation segment of any species orvertebrate fish or wildlife which inter-breeds when mature.” A subspecies is apopulation of a species whose membershave certain physical and hereditary char-acteristics distinct from other populationsof that species. What is a “distinct popu-lation segment (DPS)?”

For several years after this, there wasconfusion. Since the scientific meanings of species and subspecies can vary, themeaning of “distinct population segment”was critically important. Congress wasbesieged with requests to clarify theterm’s meaning. Congress instructed the Secretaries of the Department of the Interior and the Department ofCommerce—the federal agencies chargedwith implementing the ESA—withproviding a clear and consistent definition.In February of 1996, the Departmentsadopted a policy to clarify their interpre-tation of DPS for the purpose of listing,delisting, and reclassifying species underthe ESA.

TriploidCheckered

Whiptail



The policy used three “tests” todetermine whether the population ofanimals was a distinct populationsegment:

1. Discreteness (distinct physical, physio-logical, ecological, or behavioral charac-teristics) of the population segment inrelation to the remainder of the species towhich it belongs;

2. The significance of the populationsegment (genetic differences, uniquelineage and area of occurrence) to thespecies to which it belongs; and

3. The population segment’s conser-vation status (threatened or endangered)in relation to the ESA’s standards forlisting.

The characteristics that wildlife biol-ogists needed to use to determinewhether a certain population was adistinct population segment has sincebeen used as a de facto (legal) definitionof species. These characteristics are:

1. Usually do not interbreed with otherpopulations;

2. Have different appearance, behavior, orecological niche than other populations;

3. Have notably different DNA (geneticmaterial that determines inherited charac-teristics); and

4. Represent a uniqueevolutionary lineage andcontain the potential fora unique evolutionaryfuture.

What is your biology textbooks’ definitionof species?

____________________________________________________________________________________________________________________________________________________________________________________________________________________________________

Does the textbook definition share any ofthe characteristics used to determine adistinct population segment? If so, whichones?

____________________________________________________________________________________________________________________________________________________________________________________________________________________________________

Why is a legal definition of speciesnecessary?

____________________________________________________________________________________________________________________________________________________________________________________________________________________________________

Pika

T h e S p e c i e s Q u e s t i o n

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• Describe the morphological andbehavioral differences of twopopulations of sage grouse

• Provide evidence that mightsupport an argument forconsidering two populations ofsage grouse as differentspecies

• Identify evidence that would beneeded to prove that two popu-lation of sage grouse representseparate species or variationsof a single species

BackgroundIn the mid-1990s, for the first

time in decades, a wholly newspecies of bird was “found” inthe continental United States.Like invisible ink suddenly materi-alizing on blank paper, a newspecies of bird emerged in thesagebrush ecosystem of westernColorado and eastern Utah. Like

invisible ink, the bird had beenthere all along, but researchershad not had the formula—theclues—to make them obvious.

The Gunnison sage grousehad long been assumed to be thesame species as the greater sagegrouse. Evidence collected forover 20 years demonstrated thatthe two differed starkly in size,appearance, behavior, and itturns out, DNA.

In this activity, studentsreview the data that led to thisfascinating discovery. Somestudents may actually be familiarwith this story, possibly becauseof the location they live in(students in Gunnison perhaps?)or because they have read aboutthis in the newspaper. If this isthe case, please insist thatstudents look at the evidenceanyway. The story of the grousepresents one of the finestexamples of the scientificprocess and “way of knowing.”


Birds Of A Feather

SummaryStudents carefully observe videos of sage grouse filmed at

two separate locations in Colorado. They observe photos ofthe birds and examine data. Based on the physical andbehavioral characteristics they observe, students hypothesizewhether the birds are the same or different species.


VocabularyAvian

Biodiversity

Carpal

Culmen

Game

Lek

Molt

Morphological

Tarsus

Lesson 2

16


Lesson 2: Birds Of A Feather


• Student Readingand Activity Pages

for Birds Of AFeather—one

photocopy per student


for A Closer Look—one photocopy

per student

• DVD player and monitor

• DVD: Sage GrouseObservation

• Laminated colorphotographs ofSage Grouse in

Location A(Gunnison County)and Sage Grouse

in Location B(Jackson County)

• Student ReadingPages—Hidden in

Plain View, onephotocopy

per student

• Laminated colordiagram comparing

Gunnison SageGrouse and Greater

Sage Grouse

Teaching Strategies1. Thoroughly read the studentmaterials for Birds Of A Feather,A Closer Look, and Hidden InPlain View.

2. Give each student the firstreading packet, Birds Of AFeather.

3. After giving studentssufficient time to read the packet,present the DVD: Sage GrouseObservation. Please allowstudents to view this short videoseveral times.

4. After students have recordedtheir observations from watchingthe video, pass the laminatedphotos of the two sage grousepopulations around the class andallow time for students to recordfurther observations.

5. Give each student the secondreading packet, A Closer Look,and allow the students to readthe packet and answer thequestions in small groups.

6. After discussing studentfindings as a class, take a poll todetermine how many studentsthink these two populations maybe different species. Record thepoll results in a visible place.

7. Give each student the lastreading packet, Hidden In PlainView. After reading the packet,ask if any students are surprisedwith the results.

AssessmentAsk students to write a grant

proposal requesting money tocontinue research on the twopopulations of sage grouse.Students must use evidence topersuade a government science

organization that the two popu-lations may be separate species,and must specifically state thenature of their new research andhow that research would resolvethe question.

Extensions• Students research Gunnison

sage grouse and report on anynew information about thespecies.

• Recently, another grousespecies was determined to betwo different species. Studentscan research this decision tore-classify different populationsof blue grouse. The interiorspecies (found in Colorado) willretain the same scientific name(Dendragapus obscurus) butthe common name has beenchanged to Dusky Grouse. ThePacific species has been splitto Sooty Grouse (D. fulig-inosus). The decision by theAmerican Ornithologists Unioncan be viewed at this web site:

http://www.aou.org/checklist/Suppl47.pdf

Also, the scientific paper that confirmed the geneticdifferences between thegrouse—Barrowclough, G.F.,J.G. Groth, L.A. Mertz and R.J. Gutierrez. 2004.Phylogeographic structure,gene flow and species status in blue grouse (Dendragapusobscurus) Molecular Ecology13:1911–1922.—can be foundat:

http://www.cnr.umn.edu/fwcb/research/Owls/lit%20folder/barrowclough%20et%20al.%202004.pdf


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2006 September/October issue of ColoradoOutdoors, published by the Colorado Divisionof Wildlife.

Key to Birds Of A Feather1. Observations of Sage Grouse in LocationA—Gunnison County Answers may vary—these are possibilities:The male sage grouse in Gunnison Countyhave thick feathers on the back and sidesof their necks—it looks almost like aponytail. These sage grouse seem todisplay at slower rates and they pop theirair sacs nine times during each display.The males throw their neck feathers overtheir heads and wag their tails at the endof each display. They have distinct whitemarkings on their tails.

2. Observation of Sage Grouse in LocationB—Jackson County Answers may vary—these are possibilities:The male sage grouse in Jackson Countyhave thin feathers on the back and sides oftheir necks. They pop their air sacs twiceduring each display.

Key to A Closer Look1. What general statement can you makeabout sage grouse wings when you comparemales and females? Female sage grousewings are smaller than male sage grousewings.

2. What general statement can you makewhen you compare sage grouse wingscollected in Gunnison County with wings inJackson County? Sage grouse wingscollected in Gunnison County are smallerthan sage grouse wings collected inJackson County.

3. Based on this additional data, whatgeneral statement can you make about sagegrouse when you compare males andfemales? Female sage grouse are smallerthan male sage grouse.

4. What general statement can you makewhen you compare sage grouse in GunnisonCounty with sage grouse in Jackson County?The sage grouse in Gunnison County aresmaller than the sage grouse in JacksonCounty.

5. What are the legal criteria for defining aspecies?

• Usually do not interbreed with otherpopulations;

• Have different appearance, behavior,or ecological niche than other popu-lations;

• Have notably different DNA (geneticmaterial that determines inheritedcharacteristics); and

• Represent a unique evolutionarylineage and contain the potential for aunique evolutionary future.

6. Based on your observations, do thesepopulations of sage grouse meet any of thecriteria to be considered different species?Yes, they are different in appearance andbehavior. Since they are different sized, itwould be logical that they would havedifferent DNA.

7. What other information would you needbefore you could determine whether thesetwo populations of sage grouse belonged todifferent species? I would need to know ifthese birds would interbreed with eachother if given the chance and I would haveto analyze the DNA of both populations todetermine if it was different.



Notes

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Lesson 2

That Seventies Show!It is the 1970’s and biologists are

studying sage grouse in Colorado. Sincethe 1950’s, sage grouse have historicallybeen grouped into two subspeciesbased on plumage and coloration. Thewestern subspecies is limited to west-central Oregon and Washington, whilethe eastern subspecies occupiessagebrush habitat to the east of thosestates, including Colorado.

The sage grouse is one of NorthAmerica’s most spectacular birds. As itsname suggests, sage grouse live only insagebrush habitat, which provides thebirds with food and shelter, and spacefor their traditional courting ritual. Eachspring, males begin the mating ritual bycompeting for the best position in thecenter of grouse strutting grounds,called leks.

Mates of all species of sage grouseare equipped with air sacs on theirbreasts, which they use to attractfemales. The mating call that male sagegrouse make with their air sacs isaudible a mile or more away, and hasbeen compared to the sound of bubbles,or gulps, underwater. The superiority (asdetermined by other grouse) of themale’s call, and the vigor and quality ofthe rapid head-shaking, strutting dancethat accompanies it, determine itsposition in the lek. Dominant malesoccupy the center of the lek and win theopportunity to breed with the majority offemales.

You are about to view a video ofstrutting male sage grouse filmed in twodifferent locations in Colorado. Watchand listen carefully, then record yourobservations of the birds in bothlocations.

1. Observations of Sage Grouse inLocation A—Gunnison County

________________________________________________________________________________________________________________________________________________________________________________________________________________________

________________________________________________________________________________________________________________________________________________

2. Observation of Sage Grouse inLocation B—Jackson County

________________________________________________________________________________________________________________________________________________________________________________________________________________________

________________________________________________________________________________________________________________________________________________

Student Page

Birds Of A Feather



Photographers travel to Coloradofrom all parts of the world to capture thestunning sage grouse courtship on film.One well-known wildlife photographerhas traveled to the leks in bothGunnison and Jackson Counties andhas taken spectacular pictures. As youview his photos, add any observationsyou might have to your list.

Winging ItIn Colorado, sage grouse are

managed as a small game species, onethat peoplecan legallyhunt for food.In order tosustain healthypopulations ofgame animals,wildlifeagencies suchas the DOWregulatehunting bymany means.These caninclude:

• setting seasons—establishing certaintimes of year people may hunt;

• issuing licenses that limit the numberof people who may hunt; and

• setting bag limits—allowing only acertain number of animals to beharvested within a set time limit.

Game populations are closelymonitored and hunting regulations areadjusted as needed to conserve theseanimals for future generations. The sagegrouse harvest was monitored throughwings turned in by hunters to DOW biol-ogists. The wings indicate the age andsex of the grouse.

Student Pages

A Closer Look

Photo courtesy ofBill Haggerty


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How Do Sage Grouse Wings Indicate Age of the Birds?All grouse have ten primary feathers—

eventually. When the chicks hatch, theyhave only eight juvenile primaries on eachwing. Juvenile primaries 9 and 10 emergewhen the chicks are about a month old.

Grouse molt (drop and replace) theirprimaries in sequence, starting with P1and ending with P10. Adults and yearlingsreplace all ten of their primaries, butjuveniles just replace the first eight. Theydo not molt P9 and P10 until they are

14–16 months old. In the fall, whenhunting is permitted, P9 and P10 are newand pointed on the juvenile birds, pointedand worn on yearling birds, and roundedon adult birds.

How do researchers tell the sex of thesage grouse by the wings? You will soondiscover the answer!

Adult Sage Grouse

Juvenile Sage GrouseWing

P1

P2

P3

P4

P5

P6

P7

P8

P9 (pointed)P10 (pointed)

1

23

45

67

8

9*

10*

*Rounded



Dr. Clait Braun, an avian (bird)researcher with the DOW, began compilingthe wing data for sage grouse populationsin the mid-1970’s. He measured threeprimary feathers (10, 9, and 1) on eachwing. Here are the data he has for twodifferent locations—the Gunnison Basin ofsouthwestern Colorado and those fromJackson County in the northwestern partof the state:

What general statement can you makeabout sage grouse wings when youcompare males and females?

____________________________________________________________________________________________________________________________________________________________________________________________________________________________________

What general statement can you makewhen you compare sage grouse wingscollected in Gunnison County with wingsin Jackson County?

____________________________________________________________________________________________________________________________________________________________________________________________________________________________________

Dr. Braun had the same observationsthat you did and decided to investigateother morphological (physical) traits ofthe birds. He decided to compare otherphysical characteristics of the two populations of birds. Here is his datacomparing various features of adult maleand adult female sage grouse in Gunnisonand Jackson Counties. All numbersrepresent the mean measurement for eachfeature.

ADULT MALES ADULT FEMALES

P10 P9 P1 P10 P9 P1

Gunnison CountyMean Length

(mm)166 216 151 139 182 130

Jackson CountyMean Length

(mm)179 230 167 147 193 141

*Explanation of body part and meas-urement:

• Culmen: Straight-line measurement fromthe base of the upper beak to the tip ofthe upper beak

• Tarsus: Measurement from pointwhere the leg joins the middle toeto the first joint in the leg

• Carpal: With the wing slightlyflattened, measurement from thewrist bone of the wing to the tip ofthe longest primary feather


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Juvenile Sage Grouse Wing

P1 P2 P3 P4 P5P6

P7P8

P9 (pointed)

P10 (pointed)

GUNNISON COUNTY JACKSON COUNTY

Adult Males Adult Females Adult Males Adult Females

Live Body Mass (g) 2,141 1,204 3,190 1,745

Beak Measurements (mm) Culmen* 31.7 28.0 39.1 30.6

Nostril to tip 14.3 12.9 16.6 14.5 Width 16.0 13.8 21.7 17.1

Tarsus Length (mm)* 62.5 58.6 74.4

Carpal Length (mm)* 304 260 340 284

Length of Tail Feathers (mm) <315 347

Carpal Length Measurement

Culmen

*Explanation of body part and measurement:

Tarsus



Based on this additional data, whatgeneral statement can you make aboutsage grouse when you compare malesand females?

____________________________________________________________________________________________________________________________________________________________________________________________________________________________________

What general statement can you makewhen you compare sage grouse inGunnison County with sage grouse inJackson County?

________________________________________________________________________________________________________________________________________________________

What are the legal criteria for defining aspecies?

1. ________________________________________________________________________________________________________________

2. ______________________________________________________________________________________________________________________________________________________

3. ________________________________________________________________________________________________________________

4. ________________________________________________________________________________________________________________

Based on your observations, do thesepopulations of sage grouse meet thecriteria to be considered different species?

________________________________________________________________________________________________________________________________________________________

What other information would you needbefore you could determine whether thesetwo populations of sage grouse belongedto different species?

________________________________________________________________________________________________________________________________________________________


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In 1977, Dr. Clait Braun, an avianresearcher with the DOW, noticed thatsage grouse wings collected in theGunnison Basin of southwestern Coloradowere smaller than sage grouse wingscollected in northern Colorado. He alsonoted that these grouse were one-thirdsmaller than the sage grouse found farthernorth, and that the males had moredistinct, whiter tail feathers and moreelaborate filoplume feathers on theirnecks. Dr. Braun also documenteddifferences in leg lengths and beakshapes. Based on these morphological(physical form and structure) differences,he began to think that the birds in theGunnison Basin might be anothersubspecies.

Sound from the strutting groundsprovided some of the first strong hints thatthe two groups might in fact be separatespecies. As an undergraduate student atthe University of California at San Diego inthe 1980’s, Jessica Young had foundherself listening to and trying to analyzehundreds of tapes of sage grouse as partof a biology project. She noticed differentvocal patterns on tapes of sage grousefrom the Gunnison Basin. While sagegrouse from northern areas such asJackson County consistently pop their airsacs twice in each of the many brief strutdisplays they perform, the Gunnison birdspop their air sacs nine times, and thesounds they produced are notably deeper.

Fascinated by startling differences invocal patterns, she rounded up video andaudio recorders and went to the leks tostudy the entire mating ritual. Male sagegrouse in both the Gunnison and northernareas had a highly elaborate strut displaythat began with males taking a few steps,and then raising their wings and brushingthem twice against the stiff feathers of thepouch to make swishing noises toaccompany the mating calls. She notedthat sage grouse in Gunnison had fewerdisplays per minute and would also throwtheir filoplumes over their head and wagtheir tail at the end of their display.

When Jessica Young tried to play maleGunnison County grouse vocalizations inthe territories of Jackson County sagegrouse, the females actively avoided thearea. She had similar results when shetried to romance Gunnison females withthe sounds of Jackson County sagegrouse males. Young continued to studythe Gunnison grouse and to collaboratewith Dr. Braun while receiving a Ph.D. atPurdue and, later, after being named tothe faculty at Western State College,which is in Gunnison.

Student Pages

Hidden In Plain View



At first, Dr. Braun was hesitant tocome to the extraordinary conclusion thatthe Gunnison grouse was a separatespecies. Nevertheless, in time, heconceded that Dr. Young simply compiledtoo much evidence to conclude otherwise.Dr. Young’s research on the behavioraldifferences of the sage grouse, along withDr. Braun’s documentation of morpho-logical differences, led to analysis of thebirds’ genetics in 1999. The DNA studies,by Dr. Tom Quinn and Dr. Sara Oyler-McCance of Colorado State University,provided definitive evidence that the twogroups were separate species.

This was the first time in decades thata new species of bird was described in thecontinental United States. The Gunnisonsage grouse did not interbreed with thenorthern sage grouse; the two arestrikingly different in both appearance andbehavior; and detailed studies of the twogroups’ DNA showed that they were fartoo distantly related to be considered thesame species. Unlike new speciesdiscoveries in remote parts of the globe,the Gunnison sage grouse had been inplain view all along!

By the way, the sources of the dataprovided for this activity were:

• Hupp, J.W. and C.E. Braun. 1991.Geographic variation among SageGrouse in Colorado. Wilson Bulletin 103(2), 255–261.

• Young, J.R., C.E. Braun, S.J. Oyler-McCance, J.W. Hupp, and T.W. Quinn.2000. A new species of Sage-Grouse(Phasianidae: Centrocercus) fromSouthwestern Colorado. Wilson Bulletin112 (4), 445–453.


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• Describe different systems ofclassifying organisms.

• Classify organisms using twodifferent systems of classifi-cation.

• Define cladistics and describeits use.

• Describe the process used toconstruct a cladogram bycomparing ancestral andderived characters.

BackgroundThere is an amazing diversity

of life. To be able to commu-nicate about various organismsand have a significant way tostudy them, humans have alwayssought to sort species into mean-ingful groups, or taxa (taxon,singular). Before the advent ofmodern, genetically basedstudies of animals and plants,organisms were classified intodifferent categories based ontheir physical characteristics.Often, these groupings were alsoreflective of the world view at thetime and the importance placed

on different attributes of theorganism.

As advances in science haveallowed us to understand howorganisms arise and are related,classification became only oneaspect of systematics, the muchlarger field of biology that dealswith the diversity of life.Systematics includes bothtaxonomy, the science ofnaming and classifyingorganisms, and phylogenetics,the study of the pattern of eventsthat has led to the distributionand diversity of life.

Cladistics is a method ofanalysis that attempts to classifyorganisms by common ancestry.It has been around for almostfifty years, but has really becomeimportant in the past fewdecades, as a means of hypothe-sizing relationships amongspecies that can then be testedwith new molecular technologies.High school texts are nowbeginning to introduce studentsto these important concepts.

This activity takes studentson a historical journey throughthe classical methods oftaxonomy into the new age ofsystematics. This compact pres-entation of changes in scientific


Taxonomy Through The Ages

SummaryStudent groups prepare taxonomic groupings that reflect

the science of different time periods by rearranging picturesof 24 species of Colorado wildlife.

Duration Two or three 45-minute class periods

VocabularyAncestral character

Binomial

Character

Clade

Cladistics

Cladogram

Classificationsystem• Five-kingdom• Three-domain• Two-empire

Derived character

DNA

Eukaryote

Gene

Gene sequencing

In-group

Marine

Natural selection

Out-group

Phylogenetics

Prokaryote

Selection

Strata

Systematics

Taxon (taxa)

Taxonomy

Terrestrial

Uniformitarianism

Lesson 3

28




• Student Readingand Activity

Packet: TaxonomyThrough The Ages

• Copies ofColorado Wildlife

Cards—one per student

• Scissors

• Glue or tape

• Poster board,butcher paper or

other presentationmedia

• Access totextbooks, library,

and internet

thought over time can alsofacilitate discussions on theprocesses of science and therelationship of scientific advancesto human history.

Teaching Strategies1. Thoroughly read the studentmaterials for Taxonomy ThroughThe Ages.

2. Divide the class into groupsof two to four students.

3. Give each student a copy ofthe Colorado Wildlife Cards andthe activity packet, TaxonomyThrough The Ages.

4. Introduce the idea thatscientific ideas and proceduresmay change as new discoveriesand advances are made. Tellstudents that they will beexploring the developing scienceof the classification of organisms,and will later see how classifi-cation relates to larger speciesquestions.

5. Tell students that they willwork through parts I and II of theactivity in their groups. Showthem the resource materials(textbooks, library books, andinternet) and the presentationmaterials that are available tothem. To research classificationof animals, one of the bestInternet sites is University ofMichigan Museum of ZoologyAnimal Diversity Web:

http://animaldiversity.ummz.umich.edu/site/index.html

Students can type the scientificor common name into the searchbox and find the taxonomicgroups of each species. This sitealso provides links to othertaxonomy sites.

6. Allow class time for studentsto read through parts I and II ofthe activity and to prepare,present, and defend their classifi-cation posters to theirclassmates.

7. Point out to students thatAristotle’s system might includesome animals in the correctgroup. He might have groupedbats in the “bird” taxa. He maynot have recognized bats asmammals, or for that matter,have had a category formammals. His system might havealso grouped an organism like aduck billed-platypus, anotherunusual mammal, in the taxa“Four-legged animals that layeggs.” The importance of certainattributes of species, such ashaving mammary glands, haschanged over time.

8. As a class, read and discussPart III: Evolution Theory,Genetics, And Biotechnology. Besure that students understandthe terms that are being used—particularly character, ancestralcharacter, derived character, in-group and out-group. You maywant to have students circle thein-groups and out-groups on thealternate forms of the cladogramprovided.

AssessmentStudents’ preparation and

defense of their classificationposters serve as an assessmentfor this activity.

ExtensionIf the students’ textbooks

have additional examples ofcladograms, review and discussthose as well.


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Taxonomy Through The Ages KeysKey: Aristotle’s Classification

Something similar to the followinggroupings of Blooded Animals should bepresented:

• Four-legged Animals that Give Birth:

Black-footed ferret, Mustela nigripes

Lynx, Lynx lynx

Mule deer, Odocoileus hemionus

American elk, Cervus elaphus

White-tailed deer, Odocoileus virginianus

Bison, Bison bison

Pronghorn, Antilocapra americana

Black-tailed prairie dog, Cynomys ludovicianus

Red fox, Vulpes vulpes

Moose, Alces alces

Mountain lion, Felis concolor

Bighorn sheep, Ovis canadensis

Mountain goat, Oreamnos americanus

• Four-legged Animals that Lay Eggs:

Wood frog, Rana sylvatica

Boreal toad, Bufo boreas

Tiger salamander, Ambystoma tigrinum

Western box turtle/Ornate box turtle, Terrapene ornate

Triploid checkered whiptail, Cnemidophorus neotesselatus

• Snakes:

Western rattlesnake, Crotalus viridis

• Birds:

Gunnison sage grouse, Centrocercus minimus

Burrowing owl, Athene cunicularia

Sandhill crane, Grus canadensis

Little brown bat, Myotis lucifugus

• Fishes:

Rainbow trout, Oncorhynchus mykiss

Key: Classical Taxonomic Classification ofColorado Wildlife Species

Colorado Classical Taxonomic Wildlife ClassificationSpecies For Each Species The Following Groups

Are Identical:Kingdom: Animalia Phylum: Chordata Subphylum: Vertebrata

Black-footed ferret Class: MammaliaOrder: CarnivoraFamily: Mustelidae Name: Mustela nigripes

Lynx Class: MammaliaOrder: CarnivoraFamily: FelidaeName: Lynx lynx

Mule deer Class: MammaliaOrder: ArtiodactylaFamily: CervidaeName: Odocoileus hemionus

American elk Class: MammaliaOrder: ArtiodactylaFamily: CervidaeName: Cervus elaphus

White-tailed deer Class: MammaliaOrder: ArtiodactylaFamily: CervidaeName: Odocoileus virginianus





Wood frog Class: AmphibiaOrder: AnuraFamily: RanidaeName: Rana sylvatica

Boreal toad Class: AmphibiaOrder: AnuraFamily: BufonidaeName: Bufo boreas

Tiger salamander Class: AmphibiaOrder: CaudataFamily: AmbystomatidaeName: Ambystoma tigrinum

Western rattlesnake Class: ReptiliaOrder: SquamataFamily: ViperidaeName: Crotalus viridis

Western box turtle/ Class: ReptiliaOrnate box turtle Order: Testudines

Family: EmydidaeName: Terrapene ornata

Triploid checkered Class: Reptiliawhiptail Order: Squamata

Family: Teiidae Name: Cnemidophorus neotesselatus

Gunnison sage Class: Aves grouse Order: Galliformes

Family: Phasianidae Name: Centrocercus minimus

Rainbow trout Class: OsteichthyesOrder: SalmoniformesFamily: SalmonidaeName: Oncorhynchus mykiss

Little brown bat Class: Mammalia Order: ChiropteraFamily: Vespertilionidae Name: Myotis lucifugus



Bison Class: MammaliaOrder: ArtiodactylaFamily: BovidaeName: Bison bison

Pronghorn Class: MammaliaOrder: ArtiodactylaFamily: AntilocapridaeName: Antilocapra americana

Black-tailed Class: Mammaliaprairie dog Order: Rodentia

Family: Sciuridae Name: Cynomys ludovicianus

Red fox Class: MammaliaOrder: CarnivoraFamily: CanidaeName: Vulpes vulpes

Moose Class: MammaliaOrder: ArtiodactylaFamily: CervidaeName: Alces alces

Mountain lion Class: Mammalia Order: Carnivora Family: Felidae Name: Felis concolor

Bighorn sheep Class: Mammalia Order: Artiodactyla Family: Bovidae Name: Ovis canadensis

Mountain goat Class: Mammalia Order: Artiodactyla Family: BovidaeName: Oreamnos americanus

Burrowing owl Class: Aves Order: StrigiformesFamily: StrigidaeName: Athene cunicularia

Sandhill crane Class: AvesOrder: GruiformesFamily: GruidaeName: Grus canadensis


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Key: Linnean Classification

Something similar to the following:Kingdom Animalia

Phylum Chordata

Subphylum Vertebrata

Class

Osteichthyes

Class Amphibia

Order Salmoniforms

Order Anura

Family Salmonidae

Rainbow trout,Oncorhynchus

mykiss

Family Ranidae

Family Ambystomatidae

Tiger salamander,Ambystoma

tigrinum

Order Caudata

Class Reptilia

Family Bufonidae

Wood frog,Rana sylvatica

Boreal toad,Bufo

boreas

Order Squamata

FamilyVeperidae

Family Emydidae

Western box turtle/

Ornate box turtle,Terrapene

ornate

Order Testudines

Family Teiidae

Westernrattlesnake,

Crotalus viridis

Triploid checkered whiptail,

Cnemidophorusneotesselatus

Class Aves

Order Galliformes

Family Strigidae

Burrowing owl,

Athene cunicularia

Order Strigiformes

Family Phasianidae

Gunnison sage grouse,Centrocercus

minimus

Family Gruidae

Sandhill crane,Grus

Canadensis

Order Gruiformes



Class Mammalia

Family Mustelidae

Black-footed ferret,

Mustela nigripes

Family Felidae

Lynx,Lynx lynx

Mountain lion,Felis concolor

Family Canidae

Red fox,Vulpes vulpes

Order Carnivora

Order Rodentia

Family Sciuridae

Black-tailedprairie dog,Cynomys

ludovicianus

Order Chiroptera

FamilyVespertilionidae

Little brown bat,Myotis lucifugus

Family Antilocapridae

Pronghorn,Antilocapra americana

Family Cervidae

Mule deer,Odocoileus hemionus

American elk,Cervus elaphus

White-tailed deer,

Odocoileus virginianus

Moose,Alces alces

Family Bovidae

Bighorn sheep,Ovis

canadensis

Mountain goat,

Oreamnos americanus

Bison,Bison bison

Order Artiodactyla


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BisonBison bison



Black-footed ferretMustela nigripes

LynxLynx lynx

Mul

e de

erOd

ocoi

leus

hem

ionu

s

White-tailed deerOdocoileus virginianus

American elkCervus elaphus

Pron

ghor

nAn

tiloc

apra

am

eric

ana

Black-tailed prairie dog

Cynomys ludovicianus


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Red

fox

Vulp

es v

ulpe

s

Mountain lionFelis concolor

Bigh

orn

shee

pOv

is

cana

dens

is

Mountain goatOreamnos

americanus

MooseAlces alces

Burr

owin

g ow

lAt

hene

cun

icul

aria

Sandhill craneGrus

canadensis

Wood frogRana sylvatica


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Bore

al to

adBu

fo b

orea

s

Western box turtle/Ornate box turtleTerrapene ornata

Tiger salamanderAmbystoma tigrinum

Triploid checkered whiptailCnemidophorus neotesselatus

Gunn

ison

sag

e gr

ouse

Cent

roce

rcus

min

imus

Western rattlesnakeCrotalus

viridis

Rain

bow

trou

tOn

corh

ynch

usm

ykis

s

Little brown batMyotis lucifugus


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Student Pages

Taxonomy Through The Ages



Since ancient times, humans havebeen grouping and classifying all typesof things. Sorting objects or living thingsinto categories may have begun as aprimal means of survival. Labeling oridentifying other people or tribes asfriends or enemies, plants as edible orpoisonous, or animals as safe ordangerous could definitely help keepone alive.

This time-honored human method ofbringing order to the world also helps usorganize information we have aboutorganisms and biodiversity. For example,if someone discovers a new species andgroups it with similar animals that havealready been studied, he would not needto analyze everything about the neworganism from scratch. The process of sorting out and classifying life alsohelps biologists answer many speciesquestions.

The science of naming, describingand classifying organisms into groups iscalled taxonomy. Each named group oforganisms is called a taxon, and theplural of this word—many groups—istaxa.

Part I: AristotleAristotle (384–322 B.C.E.), an over-

achieving Greek philosopher, was thefirst to develop a widely used system ofclassification for living things. He sortedanimals according to their actions orway of life, as well as their physicalfeatures or parts. Aristotle based his

groupings on his observations of marine(ocean) and terrestrial (land) life and hisdissections of various animals. Hedivided the animals into two types: thosewith blood, and those without blood (orat least without red blood).

The blooded animals were furtherdivided into two groups: animals thatgave birth and animals that laid eggs.The animals that gave birth were placedinto three groups: humans, whales, andfour-legged animals that gave birth.Animals that laid eggs were grouped into these categories: birds, serpents(snakes), four-legged animals that layeggs, and fishes.

The bloodless animals were clas-sified as cephalopods (such as theoctopus); crustaceans; insects (whichincluded the spiders, scorpions, andcentipedes, in addition to what we nowdefine as insects); shelled animals(snails, clams, oysters, starfish, seaurchins, etc.); and “zoophytes,or “plant-animals,” which looked like

plants (such as coral, sponges, etc).

Your TaskUsing one set of your group’s wildlife

species cards; design a poster thatgroups the 24 animals according toAristotle’s classification system.

Part II: LinnaeusCarl Linnaeus was born in 1707, the

son of a Swedish Lutheran minister.Linnaeus shared his father’s interest in

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plants and loved nature deeply. Hisreligious beliefs led him to naturaltheology, a philosophy that taught that it ispossible to understand God’s wisdom bystudying His creation. The study of naturewould reveal the Divine Order of God’screation, and as a naturalist it wasLinnaeus’ task to construct a “naturalclassification” that would reveal this orderin the universe.

Linnaeus’s search for a natural systemfor the classification of living things ledhim to group organisms based on sharedcharacters—identifiable features, traits orcharacteristics. He combined his groupsinto a hierarchy of subsequently moreinclusive, higher taxonomic groups. Verysimilar species were grouped together in agenus; similar genera were grouped intoorders, and so on. Linnaeus’ first hierarchyof taxonomic groups included species,genus, order, class, and kingdom. Thehighest taxa, the kingdom, containedgroups that shared the most general char-acteristics.

What’s In A Name?

For centuries species had been givenlong, Latin names that described them.For example, the common Europeanhoney bee was called Apis pubescensthorace subgriseo abdomen fusco pedipusposticus glabris utrimque margin ciliates,meaning “the bee with a grayish thoraxand brown belly, and a hind foot that issmooth on the sides and fuzzy on themargins.” Linnaeus simplified this namingsystem by providing each species withtwo names or a binomial. The first nameof the binomial indicated the genus, orgroup of very similar organisms, that thespecies belonged to. The second namewas unique to the species. The exclusivetwo-part name for a species is nowreferred to as its scientific name. For

instance, Apis mellifera is the binomial andscientific name for the honey bee.

The scientific name of an organismgives biologists a common way ofcommunicating, no matter what theirnative language. Regardless whether theresearcher is from the United States,China, Spain or Africa, and no matter theiralphabet or form of writing, he or she willalways use the scientific name in anagreed format in any scientific publication.The first letter of the genus name isalways capitalized, and the first letter ofthe second word is always lowercase. Thescientific name is always either underlinedor in italics.

Kingdoms, Empires, And Domains

Linnaeus’s classification system hasbeen used by biologists for over 200years, although it has been slowlymodified as new discoveries were made.At first, biologists grouped all of theorganisms that they knew into twokingdoms—plants and animals. Evenmicroorganisms were grouped into thesekingdoms, depending on their color andappearance.

During the 1800’s, Ernst Haeckelproposed putting microorganisms in aseparate kingdom, the protists. This three-kingdom system was then expanded tofour in the early 1900’s, when scientistsbegan to distinguish between bacteria andother microorganisms. The new kingdomfor bacteria was called Monera.

The current five-kingdom classifi-cation system (Monera, Protista, Plantae,Fungi, Animalia) found in most high schoolbiology textbooks today was not proposeduntil 1969. Robert Whittaker proposed thatorganisms be grouped into kingdoms onthe basis of three characteristics: cell



Kingdom

Phylum

Subphylum

Class

Order

Family Family

Order

Family

Class

Order Order

Class

structure (prokaryotic cells which have nonucleus or eukaryotic cells that have anucleus), body structure (single-celled ormulticellular) and manner of getting energyor nourishment (photosynthesis,absorption, or ingestion).

Recently, two other methods of clas-sifying organisms have been suggested.Your textbook may talk about these. Thelate Ernst Mayr, a prominent biologist atHarvard, supported a two-empire classi-fication system based on cell structure.The two empires are called EmpireProkarya or Prokaryotae (prokaryotes—organisms lacking nucleated cells) and Empire Eukarya or Eukaryotae(eukaryotes—organisms having nucleatedcells).

Another noted biologist, Carl Woese,promotes a three-domain classificationsystem. He groups organisms on thebasis of the genetic makeup of theirribosomal RNA (rRNA). Just as every

species—and individual—has a uniqueDNA sequence, each species and indi-vidual has a unique rRNA sequence. Whenhe analyzed each organism’s rRNA, Woesediscovered that bacteria fall into twogenetically distinct groups, which he callsBacteria and Archaea, that are as differentfrom each other as they are fromeukaryotic organisms. Woese dividesEarth’s organisms into three domains:Bacteria, Archaea, and Eukarya.

Your TaskUsing your biology textbook and other

resources, research the names of thetaxonomic groups of the 24 wildlifespecies. Then, using a second set of yourgroup’s species cards, design a posterthat groups the animals in a Five-Kingdomclassification system. Your poster maylook a bit like a company’s organizationalchart, because all the animals share char-acters that group them in the samekingdom, phylum, and subphylum. Thechart may look a bit like this:


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You will first need to research theclassical taxonomic groups of the 24 species:

Colorado Classical Taxonomic Wildlife ClassificationSpecies For Each Species The Following

Groups Are Identical:Kingdom: Animalia Phylum: Chordata Subphylum: Vertebrata

Black-footed ferret Class:Order:Family:Name: Mustela nigripes

Lynx Class:Order:Family:Name: Lynx lynx

Mule deer Class:Order:Family:Name: Odocoileus hemionus

American elk Class:Order:Family:Name: Cervus elaphus

White-tailed deer Class:Order:Family:Name: Odocoileus virginianus

Bison Class:Order:Family:Name: Bison bison

Pronghorn Class:Order:Family:Name: Antilocapra americana

Black-tailed Class:prairie dog Order:

Family:Name: Cynomys ludovicianus

Red fox Class:Order:Family:Name: Vulpes vulpes



Moose Class:Order:Family:Name: Alces alces

Mountain lion Class:Order:Family:Name: Felis concolor

Bighorn sheep Class:Order:Family:Name: Ovis canadensis

Mountain goat Class:Order:Family:Name: Oreamnos americanus

Burrowing owl Class:Order:Family:Name: Athene cunicularia

Sandhill crane Class:Order:Family:Name: Grus canadensis

Wood frog Class:Order:Family:Name: Rana sylvatica

Boreal toad Class:Order:Family:Name: Bufo boreas

Tiger salamander Class:Order:Family:Name: Ambystoma tigrinum



Part III: Evolution Theory,Genetics, And Biotechnology

There are periods in human history inwhich discoveries and new ideas of allkinds seem to emerge out of nowhere. Ifone looks more closely, new ideasusually developed as result of combiningold ideas in a unique way. Our newestand most useful taxonomic methods—those that utilize DNA and RNA analysis,computers, and all sorts of biotech-nology—had their start in the 1800s.Those ideas had their birth thousands ofyears before, with the start of agriculture.

Building A Better Burger

Since the dawn of agriculture,humans have been trying to alter plantsand animals to give them traits that weremore desirable—a process known asselection. First, people found ways todomesticate these species. Theygathered edible grasses and plantedthem near their homes. They pennedand herded wild goats, sheep and cattleso that they would not have to spenddays looking for something to eat.

These early agriculturists noticed that offspring seemed to have traits that were similar to parents. Although itwas a complete mystery as to how ithappened, early ranchers found that ifthey bred the two woolliest sheep, theoffspring would be pretty woolly. Iffarmers wanted more grain, they wouldcross plants with the biggest and mostabundant seed heads. Over time, thisled to bigger and better food crops, well-fed people, and enough free time in theday to devote to academic pursuits.



Western rattlesnake Class:Order:Family:Name: Crotalus viridis

Western box turtle/ Class:Ornate box turtle Order:

Family:Name: Terrapene ornata

Triploid checkered Class:whiptail Order:

Family:Name: Cnemidophorus neotesselatus

Gunnison sage Class:grouse Order:

Family:Name: Centrocercus minimus

Rainbow trout Class:Order:Family:Name: Oncorhynchus mykiss

Little brown bat Class:Order:Family:Name: Myotis lucifugus


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Figuring Out Fossils

In the late 1600s, scientist RobertHooke—best known for his discovery ofthe cell—proposed that fossils were theremains of once-living organisms. Hishypothesis sounded absurd to mostpeople of his time. In the seventeenthcentury, nearly everyone thought thatfossils were formed and grew within theEarth. They thought there was a shapingforce that could create stones that lookedlike living things.

Hooke was the first person to examinefossils with a microscope. He noted closesimilarities between the structures ofpetrified wood and fossil shells on the onehand, and living wood and living molluskshells on the other. Hooke believed thatthe features he could see in fossils weresimilar to those found in living organisms.He concluded that dead plants andanimals could be turned to stone by beingsubmerged in water rich in dissolvedminerals. Over time, the minerals whichwere deposited throughout the body ofthe organism would replace each cell.

As Hooke continued to study fossilsand compare them with living organisms,he concluded that many fossils repre-sented organisms that no longer existedon Earth and that fossils could be used tounderstand the history of life.

“There have been many other Speciesof Creatures in former Ages, of whichwe can find none at present; and that’tis not unlikely also but that there maybe divers new kinds now, which havenot been from the beginning.”

This was an incredibly radical thoughtat the time. A century later, two otherscientists developed theories that wouldnot only support Hooke’s ideas, butchange our understanding of living

organisms, update Linnaeus’s taxonomichierarchy, and group organisms incompletely new ways.

Lyell And Darwin

Charles Lyell (1797–1875) was theleading British geologist of his era. Hestudied the strata—layers—of the earthand realized that each differed in thenumber, type and proportion of marineshells (fossils). Each layer represented adifferent era of Earth’s history. He foundevidence for the then-controversialhypothesis of uniformitarianism, the ideathat the earth was shaped entirely byslow-moving forces acting over a verylong period of time. He assumed that thekinds of activities which affected the earthin the past must have been exactly likethose in operation in the present (such aserosion, sediment deposition, volcanicaction, earthquakes, etc.).

Lyell’s ideas influenced a closepersonal friend of his, Charles Darwin.Comparing living organisms to fossils,Darwin (1809–1882) hypothesized thatpopulations of organisms could changeover time. Just as farmers and rancherscould slowly improve their crops andlivestock over time, he proposed that wildorganisms could slowly change by aprocess he called natural selection.Natural selection is often referred to assurvival of the fittest. Life is a constantstruggle for survival, thought Darwin, andmore individuals are produced in a popu-lation than will be able to survive andreproduce. Those individuals who possesscharacteristics that allow them to adapt totheir environment are more likely to surviveand pass on these adaptive traits to theiroffspring. Over time, an increasingproportion of a population will possess theadaptive traits.



The Gene Connection

Later research showed how physicaltraits could be passed on to future gener-ations. In 1865, Gregor Mendel’s experi-mented on peas and demonstrated thattraits could be passed to offspring propor-tionally in discrete units—later namedgenes. In 1902, a British physician namedArchibald Garrod observed that thedisease alkaptonuria is passed from onegeneration to the next in the sameproportion as the features of Mendel’speas. Garrod had discovered the firstdisease recognized to have a geneticcause!

Meanwhile, in 1882, Walter Flemmingwas able to stain chromosomes andobserve the process of cell division. In1911, while studying fruit flies, ThomasHunt Morgan found that chromosomescarry genes. By 1952, Alfred Hershey andMartha Chase discovered that genes aremade of DNA and the following year,Francis Crick and James Watsondescribed the double helix structure ofDNA. The genetic code was cracked in1968, when Marshall Nirenberg and othersfigured out that the order of the fournitrogen bases in DNA (A, G, T, and C)determines the amino acid sequence ofproteins.

The combined research clearly demon-strated that DNA coded for all the charac-teristics possessed by an organism.Anytime the order of the nitrogen basesfound in a strand of DNA changed, thechanges were passed on to offspring. Thechanges in traits that the DNA coded forwould be inherited by future generations!It seemed likely that the more traitsspecies had in common, the moresimilar their genetic code and the more“related” they were.

The New Taxonomy

According to this idea, organisms thatare more similar to one another than theyare to other organisms have descendedfrom a more recent common ancestor.Taxonomists are now actively constructinga new “natural system” for the classifi-cation of organisms based upon theevolutionary relationships of taxa.Systematics, a large field of biology thatdeals with the diversity of life, combinestaxonomy and phylogenetics, the studyof the pattern of events that led to thediversity of life.

The method of analysis that most biol-ogists use to reconstruct evolutionary rela-tionships of organisms is called cladistics.Cladistics can be used to hypothesize theorder in which different groups oforganisms evolved. Organisms that shareimportant characters are placed togetherinto taxonomic groups called clades, thatbranch from a single “twig.” With respectto two different groups or clades, acharacter is defined as an ancestralcharacter if it evolved in a commonancestor of both groups. For example, allof the 24 animals that you have been clas-sifying have a backbone or vertebra. Abackbone is an ancestral character. A traitthat evolves in one group and not anotheris called a derived character. All thebirds, mammals, reptiles and amphibianshave four limbs and fish do not. Havingfour limbs is a derived character thatevolved later. However, when comparingbirds with the other four-limbedorganisms, four limbs becomes theancestral trait. Having forelimbs (frontlimbs) developed into feathered wingsbecomes the new derived character.

After looking at the various charactersthat different groups share, scientistscreate cladograms, branching diagramsthat represent a hypothesis about theorder in which organisms evolved.


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Cladograms convey comparative infor-mation about relationships. Organismsthat are grouped more closely on acladogram share a more recent commonancestor than those farther apart. Becausethe analysis is comparative, cladisticanalysis deliberately includes an organismthat is only distantly related to the otherorganisms. This distantly related organismis called an out-group. The out-groupserves as a base line for comparison withthe other organisms being evaluated, thein-group.

Construction A Cladogram

The first step in constructing acladogram involves analyzing characters ina data table. The table below will be usedto record whether characters are presentor absent in several vertebrate speciesyou have been studying. A non-vertebrate,or animal that doesn’t have a backbone,will represent the out-group for ourcomparison. Notice that the all the traits inthe column for the out-group are markedwith a 0, which means that the animaldoes not have the character. If theorganism has the new derived character,the column is marked with a 1.

CHARACTER (Character Present = 1) (Character Absent = 0)

Vertebrate Cladistic Analysis

Vertebrae or backbone 0 1 1 1 1

Four limbs 0 0 1 1 1

Embryo surrounded by water and enclosed within specialized 0 0 0 1 1membranes (amniotic egg)

Forelimbs function as wings 0 0 0 0 1

Rain

bow

Tro

ut

Star

fish

(Out

-gro

up)

Tige

rSa

lam

ande

r

Orna

te B

oxTu

rtle

Burr

owin

g Ow

l



The second step is to draw a diagonalline. The bottom of the line represents theremote past. The top of the line isrepresents a more recent time. Eachbranch that is drawn from the diagonal linewill represent a clade (group oforganisms). Now, starting with a diagonalline to represent evolutionary time, theout-group (starfish) is placed on thelowest, “oldest” branch. All the in-grouporganisms will be found on the upper ormore recent branches.

Between each branch that is drawn onthe cladogram, a derived feature is listed.Just past the first branch, the mostcommon derived character—having abackbone—is listed. Between the secondand third branch, the next most commonderived character—four limbs is listed,and so on. The clade that has the leastcommon derived character, which isthought to be the character that mostrecently occurred, occupies the upperbranch.

Vertebrae

Rain

bow

Tro

ut

Star

fish

Tige

rSa

lam

ande

r

Orna

te B

oxTu

rtle

Burr

owin

gOw

lFour limbs

Amniotic egg

Wings


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Please—Don’t Let This Confuse You!

Cladistic analysis is a bit of a newthing and scientists haven’t agreed on aformat of presentation. So, sometimes acladogram that represents the very samething as the one we just showed you willlook like this:

Or this:

Rainbow Trout

Starfish

Tiger Salamander

Ornate Box Turtle

Rainbow Trout

Starfish

Tiger Salamander

Ornate Box Turtle

Burrowing Owl

Burrowing Owl

1

2

3

4

1

2

3

4



Or this:

The reason we are showing you thisnow is because you will see all of theseformats in magazines or newspapers andalso in books, and some of the activitiesyou will be doing. Think of this as astretching exercise for your brain. It’simportant to have a flexible body andmind!

Rain

bow

Tro

ut

Starfish

Tige

r Sa

lam

ande

r

Orna

te B

ox T

urtle

Burr

owin

g Ow

l

2

1

3

4

1

2

3

4

Vertebrae

Four limbs

Amniotic egg

Wings


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• Define cladistics and describeits use

• Read a cladogram anddescribe the information that itillustrates

• Sort through various charactersof limb structure, toothstructure and dentition, form ofstomach and type of horn anddecide which characters areancestral and which are derived

• Construct a cladogram thatdemonstrates the phylogeny ofnine groups of ungulates

• Describe how cladistics is usedto classify organisms intogroups

BackgroundSystematics, a large field

of biology that deals with thediversity of life, combinestaxonomy and phylogenetics,the study of the pattern of eventsthat have led to the distributionand diversity of life. Cladistics isa system of analysis used bybiologists to reconstruct the

pattern of events that led to thedistribution and diversity of life,both living and extinct. It wasfounded by Willi Hennig, aGerman entomologist in 1950,and in the past few decades hasbecome the most commonlyused method to examine evolu-tionary relationships oforganisms.

Cladists, biologists who usecladistics, use the appearance of what they believe to bederived or newly evolved traits to assemble organisms intogroupings—taxa—that appear torepresent the evolutionary historyof the species. All members ofeach natural group are thought tobe monophyletic, to have char-acteristics in common becausethey evolved from a commonancestor. These monophyletictaxa are called clades. Afterlooking at the various charactersthat different clades share,cladists create cladograms,branching diagrams thatrepresent a hypothesis about the order in which organismsevolved. They can then test theirhypotheses about species rela-tionships through DNA and rRNAsequencing, computer modelingand other techniques.


Understanding Ungulate Phylogeny

SummaryStudents use cladistics to determine the evolutionary

history of nine groups of ungulates.


VocabularyAncestral characters*ArtiodactylsBrachydontBunodontCaninesCannon boneCarpalsCharacter*Clades*Cladist*Cladistics*Cladogram*Derived characters*DiastemaDigitigradeDigitsHerbivorousHomologous

structures*HypsodontIncisorsIn-group*MesaxonicMetacarpalsMetatarsalsMetapodialsMolarsMonophyletic group*Out-group*ParaxonicPerissodactylsPhylogeny*PlantigradePremolarsRuminantsSelenodontStanceTarsalsUngulate*Unguligrade

Lesson 4

52


Lesson 4: Understanding U

ngulate Phylogeny



from Lesson 3,Taxonomy throughthe Ages—retained

by each student


UnderstandingUngulate

Phylogeny—oneper student

• Importantvocabulary words,

those with an *,posted in a

visible place

Cladistic hypotheses aboutthe relationships of organismscan also be used to predict traitsor characteristics of theorganisms. For example, if biol-ogists are searching for particulargenes or biological compoundsto improve crop yield or producemedicines, cladistics can helpnarrow the range of organismsthat need to be examined.Cladistics can also be used todetermine the genetic differencesbetween different populations forspecies conservation plans orhelp predict resistance or vulner-ability to disease in certainorganisms.

Teaching Strategies1. Thoroughly read the studentmaterials for UnderstandingUngulate Phylogeny.

2. Copy and post a list of thestarred (*) vocabulary words in ahighly visible place. These are theonly words that students shouldbe held accountable for defining.


4. You may wish to havestudents read and completeUnderstanding UngulatePhylogeny on their own.However, it is recommended thatyou review what cladogramsportray and how they areconstructed with your students.This review takes another look atthe cladogram from Lesson 3,Taxonomy through the Ages. Firstreview the data tableconstruction with students.Emphasize that organisms thatpossess a trait receive a (1) in thetable. If they lack that trait theyreceive a (0). Make sure thatstudents notice that as new

derived traits appear, all of theorganisms “downstream” fromthis change also receive this newcharacter from their ancestors.

5. After reviewing the vertebratecladogram, students use thesesame procedures to generate acharacter table and cladogramfor ungulates, hoofed mammals.

6. Students must first look atthe Table of Ungulate Charactersand answer some analysisquestions. These questions willhelp students look at differentcharacters in a way that will helpthem do their cladistic analysis.

7. The table Ungulate CladisticAnalysis is started for studentsand includes the one characterthat defines Artiodactyls, a typeof ungulate. The character isparaxonic symmetry—having the symmetry of the foot passbetween the third and fourthdigit. Notice that when charactersare assigned to the out-group(rhinos), the out-group possessesnone of the characters ofArtiodactyls. Having a group thatpossesses all (0) scores providesa place to “root” the phylogenetictree or cladogram. Encouragestudents to assign characters tothe table in a dichotomousfashion. That is, each characterlisted should include all of theremaining species with (1) scoresexcept one.

8. After students complete thisassignment, you may wish tohave students share and defendtheir cladograms. Some studentsmay complain that there are notenough characters listed in thetable to completely—or easily—sort the species. You canrecommend further research or discuss the difficulty inconstructing cladograms. Remindstudents that cladogramsrepresent testable hypotheses of


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evolutionary relationships. Cladograms arejust ideas that scientists have that they cantest with other types of technology.

AssessmentStudents’ preparation and defense of their

cladograms represent an assessment for thisactivity.

ExtensionPose the following situation to students: A

protein called a prion is thought to beresponsible for the group of diseases calledtransmissible spongiform encephalopathies(TSEs). The prion protein is a normal proteinthat has been found in most eukaryotic cellsfrom yeast to humans. An abnormally shapedprion protein is associated with these deadlyneurological diseases. Evidence indicates thatabnormally shaped prion proteins caninfluence normal prion molecules to assumethe same abnormal shape. Evidence alsoshows that the abnormal prions that causeTSEs have appeared to be of different“strains” that can affect the prions of somespecies, but not others. The relatedness ofcertain species may influence the frequency oftransmission of prion diseases from onespecies to another.

The artiodactyl family Bovidae currentlycontains gazelles, sheep, musk oxen, goats,cattle and bison. Scrapie, the prion disease insheep, has been recognized since the 18thcentury. It is believed that the prion disease incattle, bovine spongiform encephalopathy(BSE), may have appeared after cattle werefed meat and bone meal containing sheepmeat with scrapie in the 1950s. How could abiologist use a cladogram to help design atestable hypothesis regarding transmission ofscrapie to cattle and other ungulate species?What types of technology would be necessaryto test this type of hypothesis? Cladogramsare used to hypothesize the evolutionary

relatedness of species. The artiodactyls inthe same clade should be the most similarand might have a greater potential totransmit disease between species.Biologists would need to extract prionprotein from the species thought mostclosely related and do DNA or RNAsequencing to check to see if the prionswere indeed similar.

Key: Analysis Questions1. How does the number of toes differbetween the rhinoceros and other ungulategroups in the table? Rhinos have three (anodd number of) toes while the otherungulates have two or four toes. Also,rhinos are mesaxonic and all others areparaxonic. Therefore, rhinos are perisso-dactyls and all others are artiodactyls.

2. Which character is ancestral in the“Stomach” column, and which seems to bemost recently derived? A simple, 1-chambered “gut” is ancestral (it’s acharacter of the out-group, the rhino),while the complex 4-chambered, rumi-nating “gut” is the most recently derived.

3. Which families could be regarded as “trueruminants”? According to the table, “trueruminants” with complex 4-chambered,ruminating “gut” would includeAntilocapridae (pronghorn), Giraffidae(giraffe), Bovidae (sheep, musk ox, cattle,goat, bison), and Cervidae (deer, elk,reindeer).

4. Place the families in order according toincreasing complexity of the stomach. Rhino(Rhinocerotidae), pigs (Suidae), hippo(Hippopotamidae), camel (Camelidae),mouse deer (Tragulidae), pronghorn(Antilocarpidae), giraffe (Giraffidae), cattle(Bovidae), deer (Cervidae) in any order.

5. What other structures do those familieswith the most complex stomachs share? Theyshare the characters: paraxonic, cannonbone, unguligrade, no upper incisors, longdiastema, and bony horns or antlers.



ngulate Phylogeny6. Below is a table “Ungulate CladisticAnalysis.” The characters that you choose foryour table should separate one family orgroup from those that remain. To get youstarted, the first character has been placed inthe table for you. If quite a few characteristicsseparate the remaining members choose onlyone of those on your table. Choose thecharacter that you believe provides thegreatest advantage for survival. Tables willvary depending on the characters chosen.The data that fill the table should have apattern similar to Character Table 1 withlines exchanged according to the specieslist. Any table that a student can defensiblydemonstrate dichotomous charactersseparating clades is acceptable. Here’s anexample of a beginning of a possible table:

7. Use the data from the character table toconstruct a cladogram of Artiodactylungulates.

CHARACTERS

Ungulate Cladistic Analysis

Paraxonic 0 1 1 1 1 1 1 1 1

3 or 4 Chambered Gut 0 0 1 1 1 1 1 1 1

Ruminating Gut 0 0 0 1 1 1 1 1 1

Completely Fused Cannon Bone 0 0 0 0 1 1 1 1 1

Bony Horns or Antlers 0 0 0 0 0 1 1 1 1

Hypsodont Cheek Teeth 0 0 0 0 0 0 1 1 1

Horn Sheath or Antlers Shed Annually 0 0 0 0 0 0 0 1 1

Antlers 0 0 0 0 0 0 0 0 1

Suid

ae

Rhin

o (O

ut-g

roup

)

Hipp

opot

amid

ae

Cam

ilida

e

Trag

ulid

ea

Gira

ffida

e

Bovi

dae

Antil

capr

idae

Cerv

idae

8. Would a cladogram based upon DNAsequence data be similar to the one that youjust constructed? Probably. Explain why orwhy not. DNA carries the code for proteinsthat make structures, so any changes inDNA could also change structures codedby DNA.

Depending upon thecharacters chosen intheir analysis table,

student cladograms will vary.Here’s a possible cladogram that

represents the characters chosen in thehypothetical analysis table above.

Rhin

o

Antil

capr

idae

Suid

ae

Hipp

opot

amid

ae

Cam

ilida

e

Trag

ulid

ea

Bovi

dae

Gira

ffida

e

Cerv

idae


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Wow! The title of this lesson may seema bit intimidating. Resist the urge to raiseyour hand and ask for a pass to therestroom, the nurse, or whatever. Thisreally isn’t going to be too difficult. Keep inmind that scientists have a language oftheir own. They are not trying to confuseanyone. Just the opposite, scientists useall these crazy sounding big words tocommunicate accurately. Usually, manyscientific terms are built from words of“dead” languages—like Latin. Since noone speaks Latin anymore, the meaning ofLatin words does not change. If scientistsjust used plain ol’ American, there’s achance they could be misunderstood. In“living” languages, the meaning of wordscan change over time. For example, thinkof how your grandparents might havedefined the words “tight,” “hit,” or “cool”when they were your age. How manydifferent meanings can you think of forthese three simple words? Then, there arethose brand new words, like “blog” or“podcast.” You can see why these funkyscientific terms are necessary.

Which Came First?To speed things up, all the tough

words in this lesson are going to betranslated for you. Let’s start with the title.If you recall Lesson 3—and you probablyremember that lesson as clearly as youremember what you had for breakfast thismorning—the word phylogeny means anorganism’s evolutionary history. Anungulate is a hoofed mammal. So, in thislesson, you will be trying to figure out

which came first, the camel or the pig? Orwas it the giraffe or the cow? Or possibly,could it have been the elk or thehippopotamus?

In order to answer these questions,you need to use cladistics. Your razor-sharp memory may recollect from the lastlesson that cladistics is a method ofanalysis that biologists use to reconstructthe evolutionary history of organisms. Thatis, biologists use cladistics to reconstructthe pattern of events that have led to thediversity of life, both living and extinct. Youwill need to sort through all the variouscharacters (physical features) of thesehoofed animals and determine whichfeatures are older (ancestral) and whichare more recent (derived).

Another Big Word And A QuickReview

A basic assumption of cladistics is thatthe greater the number of shared derivedcharacters between two species orgroups, the more recent their commonancestor and the more closely they arerelated. In other words, the more similartwo organisms are, the more closelyrelated they are. Organs and body partsthat are alike in structure and origin aresaid to be homologous structures. Forexample, the front legs of an elephant, thewings of a bird, the flippers on a sea lion,and the arms of a human are allhomologous to each other. Eachrepresents a version of forelimbs. When

Lesson 4Student Pages

Understanding Ungulate Phylogeny



ngulate Phylogeny

different organisms share a large numberof homologous structures, it is consideredstrong evidence that they are related toeach other. These related organisms arethought to have had a common ancestorat some time in the past.

Let’s re-examine the cladogram of thevertebrates found in Lesson 3 to be sureyou understand how cladograms aremade. A cladogram is a diagram thatrepresents a hypothesis of the sequencein which new species evolved. Ancestraltraits are found among more groups oforganisms. Fewer groups of organismsshare derived traits that appeared morerecently.

Notice the first branching point of thecladogram. The organism that representsthe first branch is one that doesn’t sharethe common ancestral characteristic—it is the out-group. The starfish does nothave a backbone, the commonly sharedancestral trait. Each group of organismsthat represent the branches that followhas a backbone—they are part of the in-group.

Now this next statement is reallyimportant so this author is going to put itin BOLD ITALICS so that you will knowjust how important it is.

As further new characters appear, eachdescendant group or clade possessesthe new derived character AND all of theancestral characters of its ancestors.

In other words, the tiger salamander hasthe new derived character—four limbs—and a backbone. The ornate box turtle hasthe new derived character—an amnioticegg—and four limbs and a backbone. Youget the picture.

Not All Features Are CreatedEqual

When you compare all of the char-acters that each ungulate has, keep inmind that not all features are equallyimportant in determining evolutionary rela-tionships. If every single animal shares afeature, it may not be all that useful fortracing ancestry. For example, a two-opening gut (with a mouth at one end andan anus at the other) is an ancestralcharacter. Nearly all animals have a two-opening gut—from cockroaches to fish tohumans. This feature cannot tell us muchabout the relatedness of these species.

The features that are most helpful infiguring out a species’ ancestry are newermodifications of older traits—derivedcharacters. For example, many animalshave digits (fingers or toes) on theirforelimbs, but only humans, apes andmonkeys have opposable thumbs. Noother animals have this feature. Cladists(biologists who practice cladistics) try toidentify branching points where character-istics like this first appear to determinespecies’ family trees or lines of descent.Then they group the species—humans,apes, and monkeys—which share thederived character of opposable thumbsinto a clade—a group believed related bycommon origin. Clades are monophyleticgroups, meaning they have one (mono)common ancestor.

Lots Of Big Words And OneGuarantee

First, the bad news—there’s a ton ofbig scientific words in this next part. Thegood news is that these words are notones you need to memorize. Your teacherhas signed a statement guaranteeing that


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you will not be tested on the meaningsof these words. The scientific names ofall the ungulate characters are justexplained so that you can fill out a tableand draw a cladogram. Of course, if youwant to impress your friends and relativesby actually learning these words, go rightahead.

Starting At The TopMammals require a greater amount of

food than most other animals to support ahigher body temperature and provideenergy for the development and growth ofyoung. Adaptations that increase effi-ciency in finding, eating, and digestingfood are important for survival. Ungulatesare no exception. Most have specializedstomachs and teeth, adaptations thatallow them to extract the most energyfrom their food source.

Ungulates are herbivorous—planteaters. While most animals lack thedigestive enzymes needed to break down

the large amounts of cellulose found inplants, some ungulates have modifiedguts with multiple chambers which allowthem to get the most nutrition from theirfood. The first chamber acts as a fermen-tation vat where microorganisms breakdown the plant fibers and cellulose. This partially digested food is regurgitatedback into the mouth, chewed again, re-swallowed into the second chamber ofthe gut, and then passed to the third andfourth gut sections which further digestthe food. Ungulates that possess thesecomplex “stomachs” are calledruminants.

Teeth also are important in digestion.Although all vertebrates except turtles andbirds have teeth, the teeth of mammalsare the most specialized. Tooth structureis important for studying mammalianphylogeny and the process and pattern ofevolution. Premolars and molars arecheek teeth and come in various sizes andshapes to help ruminants grind their food.Premolars are usually simpler and smallerthan the molars at the rear of the mouth.Brachydont molars are low-crowned,while hypsodont molars are highcrowned. Selenodont molars have hard

enamel ridges running from back tofront. This type of molar is

common in grazers becausethese hard ridges increase

the number and size ofcutting surfaces inthe mouth. Animalswith a more varieddiet usually havebunodont teeth thatare squarish withlow rounded cusps,like human molars.

CHEEK TEETH (Molars and Premolars)

Canines

Diastema

Incisors



ngulate Phylogeny

Incisors are typically found at the frontof the mouth and are used for grasping,picking up, or biting off food. The incisorsmay be followed by a toothless gap calleda diastema. Canines are most often usedfor stabbing and holding prey. Malestypically have larger canines than femalesin species that use their canine teeth asweapons for social displays or fighting.Herbivorous species that do not captureprey may have smaller canines or lackthem altogether.

Moving To The BottomAnother important feature is

the ability to escape from beingeaten by some other animal. Inother words, it helps to be ableto run really fast. Stance, how ananimal stands, can determinehow quickly an animal can movewhile walking or running. Somespecies like humans place thefull length of the foot on theground during their stride(plantigrade), some walk onthe length of their digitslike dogs (digitigrade),and others walk on their tiptoes like deer(unguligrade). Anunguligrade stance helpsto increase stride lengthand speed. Hoofshardened with the proteinkeratin help ungulateswalk with their full weighton their toes.

Like us humans, the earliest mammalshad five digits on each limb. Digits arenumbered 1 (thumb, big toe) to 5 (“little”finger). The bones in our fingers (carpals)and toes (tarsals) are attached to thebones in our hand (metacarpals) and foot(metatarsals). Metacarpals andmetatarsals are also called metapodials.In ungulates, the 3rd and 4th metapodialsmay be fused to form a single, strongercannon bone. Walking on tiptoes,lengthening metapodials or reducing theirnumbers, and reducing the number ofdigits are adaptations for increasing stridelength and speed while reducing effort andincreasing endurance in locomotion.

Selenodent Teeth

METAP

ODIA

LS

CannonBone

Plantigrade

Digitigrafe

Unguligrade


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The number of digits or toes dividesungulates into two orders, Perissodactylaand Artiodactyla. Perissodactyls are odd-toed ungulates having either one or threeweight bearing toes. Perissodactyls aremesaxonic, the line of symmetry passesthrough their center toe—which isenlarged and bears most of the weight.Artiodactyls are even-toed ungulates withtwo or four toes. Artiodactyl have lost thefirst digit on each limb making themparaxonic—the line of symmetry passesbetween the two centermost toes andbears the body’s weight.

The Ungulate CladogramUse the information in the Table of

Ungulate Structures to answer thefollowing questions. The answers to thequestions may help you decide whichcharacters are ancestral and derived. Justlike a real cladist, you will need todetermine which characters are sharedamong the greatest number of groups.Then, construct a cladogram for the eightfamilies of ungulates. The rhinoceros(Family Rhinocerotidae) will be the out-group. Rhinos have three toes on eachfoot and are considered perissodactyls.Scientists believe that rhinos shared acommon ancestor with ancestral artio-dactyls some 83 million years ago.

Analysis Questions1. How does the number of toes differbetween the rhinoceros and otherungulate groups in the table?

____________________________________________________________________________________________________________________________________________________________________________________________________________________________________

__________________________________________________________________________________________________________________

2. Which character is ancestral in the“Stomach” column, and which seems tobe most recently derived?

____________________________________________________________________________________________________________________________________________________________________________________________________________________________________

__________________________________________________________________________________________________________________

____________________________________________________________________________________________________________________________________________________________________________________________________________________________________

__________________________________________________________________________________________________________________



ngulate Phylogeny

4. Place the families in order according toincreasing complexity of the stomach.

____________________________________________________________________________________________________________________________________________________________________________________________________________________________________

__________________________________________________________________________________________________________________

5. What other structures do thosefamilies with the most complex stomachsshare?

____________________________________________________________________________________________________________________________________________________________________________________________________________________________________

__________________________________________________________________________________________________________________

6. Below is a table “Ungulate CladisticAnalysis.” The characters that you choosefor your table should separate one familyor group from those that remain. To getyou started, the first character has beenplaced in the table for you. If quite a fewcharacteristics separate the remainingmembers choose only one of those onyour table. Choose the character that youbelieve provides the greatest advantagefor survival.

CHARACTERS

Ungulate Cladistic Analysis

Paraxonic 0

Rhin

o (O

ut-g

roup

)


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7. Use the data from the character tableto construct a cladogram of Artiodactylungulates.

8. Would a cladogram based upon DNAsequence data be similar to the one thatyou just constructed? __________________

Explain why or why not.

____________________________________________________________________________________________________________________________________________________________________________________________________________________________________

__________________________________________________________________________________________________________________



ngulate Phylogeny

TABL

E OF

UNG

ULAT

E CH

ARAC

TERS

Fam

ily

(mem

bers

)

Rhin

ocer

otid

ae(rh

inoc

eros

)[O

ut-g

roup

]

Cam

elid

ae(c

amel

s,lla

mas

)

Hipp

opot

amid

ae(h

ippo

pota

mus

)

Antil

ocap

ridae

(pro

ngho

rn

ante

lope

)

Gira

ffida

e(g

iraffe

,ok

apis

)

Trag

ulid

ae(m

ouse

dee

r,ch

evro

tain

)

Bovi

dae

(gaz

elle

,she

ep,

mus

k ox

,goa

t,ca

ttle,

biso

n)

Suid

ae(p

igs,

hogs

)

Cerv

idae

(dee

r,re

in-

deer

,elk

)

Num

ber o

f Toe

s3

44

22

44

44

Foot

Str

uctu

re/

Mes

axon

icPa

raxo

nic

Para

xoni

cPa

raxo

nic

Para

xoni

cPa

raxo

nic

Para

xoni

cPa

raxo

nic

Para

xoni

cSy

mm

etry

3rd

and

4th

NoYe

s,No

Yes

Yes

Yes

Yes

NoYe

sM

etop

odia

lsPa

rtial

ly fu

sed

Fuse

d in

toy-

shap

edCa

nnon

Bon

e?

Strid

eDi

gitig

rade

Digi

tigra

deDi

gitig

rade

Ungu

ligra

deUn

gulig

rade

Ungu

ligra

deUn

gulig

rade

Ungu

ligra

deUn

gulig

rade

Uppe

r Inc

isor

sNo

Yes

Yes

NoNo

NoNo

Yes

No

Uppe

r Can

ines

NoYe

sYe

sNo

NoYe

sNo

Yes

No

Low

er In

ciso

rsYe

sYe

sYe

sYe

sYe

sYe

sYe

sYe

sYe

s

Low

er C

anin

esYe

sYe

sNo

Yes

Yes

Yes

Yes

NoYe

s

Chee

k Te

eth

Mos

tly

Sele

nodo

ntBr

achy

dont

&

Hyps

odon

t &

Brac

hydo

nt &

Se

leno

dont

Hyps

odon

t &

Brac

hydo

nt &

Hy

psod

ont &

Br

achy

dont

Buno

dont

Sele

nodo

ntSe

leno

dont

Sele

nodo

ntBu

nodo

ntSe

leno

dont

Dias

tem

aSh

ort

Long

Shor

tLo

ngLo

ngLo

ngLo

ngSh

ort

Long

Leng

th

Gut

Sim

ple

3-ch

ambe

red;

3-

cham

bere

d;

4-ch

ambe

red;

4-

cham

bere

d;

3-ch

ambe

red

4-ch

ambe

red;

2-

cham

bere

d;

4-ch

ambe

red;

1-

cham

bere

d;

rum

inat

ing

nonr

umin

atin

gru

min

atin

gru

min

atin

gru

min

atin

g; a

rum

inat

ing

nonr

umin

atin

gru

min

atin

gno

nrum

inat

ing

4th

cham

ber i

spo

orly

dev

elop

ed

Horn

s w

ithHo

rns

of k

erat

in

NoNo

Kera

tin h

orn

Kera

tin h

orn

NoKe

ratin

hor

n No

Antle

rs,s

hed

Bony

Cor

eor

(s

ame

stuf

f as

shea

th is

she

d sh

eath

with

sh

eath

with

bon

ey

annu

ally

Antle

rs?

hum

an h

air

annu

ally

bone

y co

re,

core

,not

she

dan

d fin

gern

ails

),no

t she

dno

bon

ey c

ore


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• State the principle of parsimonyand describe how it is appliedin cladistic analysis.

• Choose six characters that maybe important to the survival ofpocket gophers and use thesecharacters to construct acharacter table for four speciesof pocket gopher.

• Evaluate three hypotheticalcladograms based on morpho-logical characters and selectthe one that most likelyrepresents the phylogeny offour species of pocket gophersusing the principal ofparsimony.

• Distinguish between a clado-gram and a phylogenetic tree.

• Evaluate three hypotheticalcladograms based on DNAsequences and select the onethat most likely represents thephylogeny of four species ofpocket gophers using theprincipal of parsimony.

BackgroundCladistic analysis is based on

the assumption that life arose onEarth only once. All the diversityof life that now exists on Earth isthought to have been producedthrough the reproduction ofexisting organisms. In otherwords, just as your students hadto have been born from parents,and they have had to have hadparents (grandparents), allorganisms have ancestors. If theevolutionary history, orphylogeny, of an organism istraced back, it connects throughshared ancestors to lineages ofother organisms.

That all life is connected in an immense phylogenetic tree is one of the most significantdiscoveries of the past 150 years.Often, evolutionary relationshipsbetween species are difficult tofigure out. This lesson discusseshow the principle of parsimony—that any hypothesis that requiresfewer assumptions is a moredefensible hypothesis—is used todetermine which cladogram

SummaryUsing the principle of parsimony, students use morpho-

logical characteristics and differences in DNA sequences to determine the most likely cladogram to represent thephylogenetic (evolutionary) relationship of four closely related species of pocket gopher.

Duration One or two 45-minute class periods

VocabularyAnalogous character

Ancestral character

Character state

Convergent evolution

Derived character

Evolutionarysystematics

Homologouscharacter

Parsimony

Phylogenetic tree

Phylogeny

Lesson 5

64


The Pocket Gopher Cladogram Conundrum


Lesson 5: The Pocket Gopher Cladogram Conundrum



for The PocketGopher Cladogram

Conundrum—one photocopy

per student

• Student PagePocket Gophers

of Colorado—one photocopy

per student

• Student PageCharacters of

Colorado PocketGophers—

one photocopy per student

hypothesis most likely representsthe phylogeny of any group oforganisms.

Teaching Strategies1. Thoroughly read the studentmaterials for The Pocket GopherCladogram Conundrum.


3. Give each student a copy ofthe The Pocket GopherCladogram Conundrum, PocketGophers of Colorado, andCharacters of Colorado PocketGophers.

4. Introduce the idea ofparsimony—that the hypothesiswith the least assumptions isusually the easiest to defend. Youcan tell students this is the“KISS” rule (Keep It Simple, Silly)of science.

5. You may wish to workthrough the example ofparsimony given in the studentpages as a class. You may needto review the form of thecladogram—that each branchrepresents a different lineage.

6. When you are convinced thatstudents understand parsimonyand how to apply the principal toevaluate conflicting cladograms,have students work in smallgroups to complete the activity.

7. After student groups havecompleted the activity, askgroups to present their data tableand show how they used theprincipal of parsimony to decidewhich of the three hypotheticalcladograms best representpocket gopher phylogeny basedon the characters that theyselected. Allow the rest of the

class to ask questions andcomment on the choices.

AssessmentStudent ability to evaluate

three hypothetical cladogramsbased on physical charactersand DNA sequences, select theone that most likely representsthe phylogeny of four species of pocket gophers, and defendtheir selection using the principleof parsimony serves as anassessment for this activity.

ExtensionStudent groups can exchange

papers and try to follow the logicof other groups. They cancomment on the selection ofcharacters. Students can thencompare the class results anddiscuss whether any particularcladogram was most useful inrepresenting the evolutionaryrelationships of pocket gophers.

Key 1. Look at the table Charactersof Colorado Pocket Gophersagain. Looking at the charactersthat have been provided and thecharacters you observed, choosesix characters that you believemight have the most impact onthe day to day survival and repro-duction of the four species ofpocket gopher. Explain why youbelieve the six characters thatyou selected would help a pocketgopher adapt to its environment.Answers will vary.

7. Is it possible to have character datasupport a different hypothesis than the DNAdata? Yes. Explain your answer. Thehypothesis supported may depend uponwhich characters or DNA sequences areused.

8. Once the most likely cladogram has beendetermined for related species, this infor-mation could be used to make predictionsabout species. For instance, if a diseasestrikes gopher species I but not gopherspecies III, what would you predict about theresistance of gopher species II and IV to thissame disease? Gopher species I and IV areclosely related, so species IV is also likely


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2. Place the six characters in the table belowand indicate the “state” for the character foreach species. Answers will vary.

3. Now look at the three hypotheticalcladograms again. Taking one character fromyour table at a time, determine where acharacter state change would have to occurto produce each species. Make a hatch mark at each position on each hypotheticalcladogram to indicate every character statechange. Answers will vary.

4. Which hypothesis most likely explains thephylogenetic history of these pocket gopherspecies using the six characters that youselected? Explain your reasoning. Answerswill vary.

5. What other types of characters, besidesexternal appearance, could be used toconstruct a data table and a cladogram?(Hint: Think about Lesson 2, Birds of aFeather?) Answers will vary but may includeinternal anatomical features, embryologicalsimilarities and differences, DNA, rRNA, orprotein sequence data, and behavioraldifferences.

6. Which cladogram most likely explains theevolutionary relationships of these gopherspecies? B Explain your answer. Using theconcept of parsimony, this hypothesisproduces the gopher species with the leastnumber of changes (8 hatch marks) basedupon DNA differences.

Cladograms Based Upon DNA Sequences

SPECIES

I II III IV

12 Hatch Marks

ANCESTOR

SPECIES

I III II IV

8 Hatch Marks

ANCESTOR

SPECIES

I IV II III

12 Hatch Marks

ANCESTOR

HYPOTHESIS A HYPOTHESIS B HYPOTHESIS C



to be affected by the disease. Gopherspecies II and III are more closely related,so species II is most likely to be resistantto the disease.

9. How are morphological characters andDNA sequence data related? DNA codes forthe different characters of an organism.

10. The scientific names of the four gopherspecies are given below.

Species I—northern pocket gopher(Thomomys talpoides)

Species II—plains pocket gopher (Geomys bursarius)

Species III—Botta’s pocket gopher(Thomomys bottae)

Species IV—yellow-faced pocket gopher(Pappogeomys castanops)

What do the scientific names of these pocketgopher species imply regarding their phylo-genetic relationships? Species I and IIIbelong to the same genus (Thomomys), sothey must be more closely related to eachother.

11. As more DNA sequences are accu-mulated, researchers gain better under-standing of the phylogenetic relationships oforganisms and may reassign the classificationgroups that organisms have previously beenassigned. Which classification groups aremore likely to be changed, a general grouping(like kingdom or phylum), a specific grouping(like genus or species), or an intermediategrouping (like orders or families) as DNA dataon species are evaluated? Any answer withsupport should be accepted because reas-signment of classification categories isoccurring at all taxonomic levels.

Notes

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Lesson 5Student Page

Pocket Gophers Of Colorado

III—Botta’s Pocket Gopher

II—Plains Pocket Gopher

IV—Yellow-faced Pocket Gopher

I—Northern Pocket Gopher

High, Fan ShapedMound, Plug

Tunnel Core

Fan ShapedMound, Plug

Mound BeneathBushes, Large,

Fan Shaped Mound, Plug



Student Page

Characters Of Colorado Pocket Gophers

Characters Of Colorado

Pocket Gophers I—Northern

Pocket GopherII—Plains

Pocket GopherIII—Botta’s

Pocket GopherIV—Yellow-faced

Pocket Gopher

Total Length 165–250 mm 180–300 mm 200–260 mm 245–300 mm

Tail Length 45–75 mm 50–90 mm 60–85 mm 68–80 mm

Hindfoot Length 25–31 mm 30–36 mm 28–33 mm 34–40 mm

Ear Length 5–7 mm 3–5 mm 5–7 mm <7 mm

Weight 100–150 grams 170–330 grams 110–215 grams 160–350 grams

Body Color Dark brown or Pale brown to Yellowish to Reddish brown(Dorsal or Back) yellowish brown yellowish-brown reddish brown

to grayish yellow; black patch behind ears

Body Color Whitish Slightly paler than Slightly paler than Buffy(Ventral or Belly) dorsal dorsal

Foot Color Whitish White Whitish Blackish

Frontal Grooves on None 2 None 1Incisors

Mammae 10 6 8 6

Shape of Entrance Mound Fan shaped mound, High fan shaped Fan shaped mound, Mound beneath plug mound, plug plug bushes, large, fan

shaped, plug

Tunnel Cores? Yes No Yes No

Eye Size Observations:

Limb and Claw:Observations:

Other Observations:


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Student Pages

The Pocket Gopher Cladogram Conundrum

In case you are wondering what thislesson is about, look at Webster’s defi-nition “2.b.” for conundrum. Life can be achallenge, and it is certainly a challenge tofigure out life—the diversity of life. Astricky as it might be to sort out evolu-tionary relationships of organisms thathave very different features, such ashippopotamuses and giraffes, it really getsdifficult when the animals look nearly alike.Usually, a biologist has to start out withseveral predictions—hypotheses—andthen choose the best one based on themost evidence.

Constructing a cladogram is the firststep in figuring out an organism’sphylogeny. Every cladogram represents ahypothesis—a possible answer to thequestions “How are these organismsrelated?” and “How might this group oftaxa have evolved from a single commonancestor?” When relationships of verysimilar species are in question, biologistsput together many different cladogramsand then look at morphological andgenetic evidence to form an argument foror against each hypothesis.

First StepsTo put together and sort through

several hypothetical cladograms for agroup of similar organisms, cladists

construct different possible cladogramsusing the steps you are already familiarwith. First, they determine someobservable characters (traits) and notetheir “states.” A character state is one of two or more possible forms for thatcharacter. For example, for a character“wings,” the possible states may be“present” and “absent.” For the character“number of digits,” possible states may be1, 2, 3, 4, or 5.

The next step is to determine whichcharacter states are ancestral and whichare derived. Usually, this is done bycomparing the group of organisms (in-group) with a more distantly relatedorganism, the out-group. If the characterhas only two states, then the task ofdistinguishing ancestral and derivedcharacter states is fairly simple: Thecharacter state which is in the out-group is ancestral and the one found only in thein-group is derived. For example, if theorganism in the out-group does not havewings, and all the organisms in the in-group do have wings, then wings arethe derived character state.

It can be a little more difficult todetermine which character state isancestral or derived when there are many possible states. Let’s consider thecharacter “digit” as an example. On thefollowing page is a group of mammalslisted with the number of digits for each:

co•nun•drum (k -n n’dr m) n. [Orig. unknown.] 1. A riddle in which afanciful question is answered by a pun. 2. a. A problem with no satis-factory solution. b. A complicated problem.

Webster’s II New College Dictionary, ©1995 Houghton Mifflin Company



If scientists compare this group ofmammals with some out-group ofterrestrial vertebrates—maybe crocodiles,turtles, or frogs—they can see that animalsin these out-groups also have 5 digits oneach limbs, so “5 digits” must be theancestral character state.

More To Think AboutThis brings up a problem, and it is not

just which character state—1, 2, 3, or 4—comes next. Clearly, humans have more incommon with horses and giraffes than theydo with crocodiles and frogs. Humans haveretained the ancestral character of “5digits” while the other mammals in this listhave not. This character may not be veryvaluable for constructing a cladogram forthese species.

Cladistics assumes that organisms thatare more similar to one another than theyare to other organisms are more closelyrelated. However, inferring relationshipsfrom similarities can be misleading. Not allhomologous characters—those inheritedfrom a common ancestor—look similar. InLesson 4, the various forelimbs of verte-brates, such as wings, flippers, arms, andlegs, were examples of homologousfeatures that did not look alike.

Also, just because characters orfeatures look similar does not mean they

are homologous. The flippers of whalesand dolphins look like and function like thepectoral fins of sharks. These body partsresemble each other because whales,dolphins, and sharks live in the same environment and all need to be effectiveswimmers to obtain food and survive. Thepaddle-like flippers of whales and dolphinsare highly modified hand bones, with fivefinger bones. The shark’s pectoral fins aresupported by cartilage. Another examplewould be the wings of a bird or the wingsof an insect. Both enable flight, but thestructure and origin of the two kinds ofwings differ. Through the process calledconvergent evolution, similarities evolve in organisms not closely related to oneanother, usually because they live in similarhabitat and have a similar way of life.Similarities that arise through convergentevolution are called analogous characters.

This takes us to the third step. Toaccomplish the task of creating plausiblecladograms, cladists must use goodjudgment. Good judgments are based onasking good questions. Are characterschosen well? Should other or additionalcharacters be considered? Could asupposed shared derived character (simi-larity inherited from a common ancestor) be the result of independent evolutionarydevelopment (convergent evolution)?

Last StepsAfter the cladist has finally decided

which characters to use, he or she moveson to the fourth step; building the data tableof characters. When the data leads toseveral possible cladograms, scientistschoose the most “parsimonious” cladogram.Using parsimony to evaluate conflictingcladograms is the fifth and final step.

Mammal Number of Digits (fingers or digits)

Human 5

Horse 1

Cow 4

Rhinoceros 3

Giraffe 2


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The rule of parsimony is that any hypothesis that requires fewerassumptions is a more defensiblehypothesis. What this means is that thecladogram that had the least number ofchanges in character states is the mostlogical. In other words, the best cladogramis the one that minimizes the number oftimes a feature must be assumed to havearisen or disappeared.

Speaking of assumptions, this authorthinks you may need to see an example ofchoosing between cladograms usingparsimony to make sense of this. So, we’llget to that pretty soon. First, you need toknow a thing or two about pocketgophers.

Colorado’s Pocket GophersYou should have in your possession

two important pages: Pocket Gophers ofColorado and Characters of ColoradoPocket Gophers. Take a look at thepictures on the page: Pocket Gophers ofColorado. The pictures show Colorado’sfour species of pocket gopher and someevidence that one could find that they livein a certain habitat. These rat-sizedrodents are named for the external, fur-lined storage pouches on each cheek.Pocket gophers are well-suited for lifeunderground. Rarely seen, they excavateextensive underground tunnel systemswith numerous forks and special sidebranches for stockpiling food, nesting, andstoring feces. They have short tails, tinyeyes, dinky ears, and strong front legswith claws for digging. Their lips closebehind their ever-growing incisors, sogophers can dig with their teeth withoutgetting a mouthful of soil.

As a pocket gopher digs, it pushes soilbehind itself. When enough loose materialaccumulates, the gopher turns around andshoves the dirt up to the surface with itschin and forefeet. The expelled dirt formslarge fan-shaped mounds. Pocket gophersplug the opening to these mounds so thatweasels and snakes cannot get in andhunt them underground.

Pocket gophers tunnel to get food,mainly green vegetation and roots.Usually, they eat in their burrows, oftenpulling entire plants underground. Whenthey feed at the surface, pocket gophersclip off vegetation around the burrow asfar as they can reach without losingphysical contact with the tunnel opening.

Now take a look at the page:Characters of Colorado PocketGophers. In addition to the characterslisted on the table, all four species ofpocket gopher share these characters:rodent shape, external fur-lined cheekpouch, short hairless tail, long claws ontoes, four toes on forelimbs, five toes onhind limbs and 20 teeth. These characterswere probably shared by some ancestorthat all four species have in common.

Your TaskPlease use the last three rows of the

table to fill in characters that you observeby looking at the illustrations of the fourspecies of pocket gopher.

Getting in the GrooveUsing the principle of parsimony, let’s

evaluate three possible pocket gophercladograms using only one character“Frontal Grooves on Incisors.” For thisexample, we will say that the ancestralcharacter is “no frontal grooves.” Each



time the character state must be changedon the proposed cladogram, we will makea hatch mark on the branch on thecladogram where the change occurs.

SPECIES

I II III IV

ANCESTOR

SPECIES

I III II IV

ANCESTOR

SPECIES

I IV II III

ANCESTOR


In Hypothesis A cladogram, therewould need to be a change that causedgrooves to form on the incisors where thetwo new lineages occur. The branch tospecies I and II would need to show thedevelopment of two frontal grooves andthe branch to species II and IV wouldneed to show the development of onefrontal groove. So, both branches wouldhave a hatch mark. Then, since species Ihas no frontal groove, there would need tobe another change in character stateshowing the loss of the two frontalgrooves where that species branches off.That change would also be indicated witha hatch mark. A similar change would alsohappen on the branch to species III,showing the loss of one frontal groove.Altogether, for the character “FrontalGrooves on Incisors,” there would be fourchanges in character state for HypothesisA. Hypothesis C would also show fourchanges in character state, designated byfour hatch marks.

In Hypothesis B cladogram, assumingthe ancestor had no frontal grooves on itsincisors, there would be one change incharacter state on the branch to species IIand IV, which each have frontal grooves.Then, because the branch to species IIwould need to indicate a change from onefrontal groove to two frontal grooves, therewould be another hatch mark on thatbranch. Hypothesis B has two characterstate changes, indicated by two hatchmarks.

According to the principal ofparsimony, Hypothesis B most likelyindicates the true phylogeny—evolu-tionary relationship—of the four species ofpocket gopher if only the one characterwas considered. Of course, cladogramsare rarely constructed soley on the basisof just one character.


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Now It's Your Turn1. Look at the table Characters ofColorado Pocket Gophers again.Looking at the characters that have beenprovided and the characters youobserved, choose six characters that youbelieve might have the most impact on theday to day survival and reproduction ofthe four species of pocket gopher.Explain why you believe the six charactersthat you selected would help a pocketgopher adapt to its environment.

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2. Place the six characters in the tablebelow and indicate the “state” for thecharacter for each species.

Pocket Gopher Characters

Character Gopher Species I II III IV

II—Plains Pocket Gopher

I—Northern Pocket Gopher



3. Now look at the three hypotheticalcladograms again. Taking one characterfrom your table at a time, determine wherea character state change would have tooccur to produce each species. Make ahatch mark at each position on eachhypothetical cladogram to indicate everycharacter state change.

4. Which hypothesis most likely explainsthe phylogenetic history of these pocketgopher species using the six charactersthat you selected? Explain yourreasoning.

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5. What other types of characters,besides external appearance, could beused to construct a data table and acladogram? (Hint: Think about Lesson 2,Birds of a Feather?)

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SPECIES

I II III IV

ANCESTOR

SPECIES

I III II IV

ANCESTOR

SPECIES

I IV II III

ANCESTOR


III—Botta’s Pocket Gopher

IV—Yellow-faced Pocket Gopher


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Cladogram Or Phylogenetic Tree?In practice, when cladograms are

constructed, many hundreds of charactershave to considered, and computers areneeded to sort out which organisms go on each branch. An advantage of cladisticsis that it is a very objective analyticaltechnique. If a data table containing thesame set of character data is fed into and analyzed repeatedly by differentcomputers, the computers will constructidentical cladograms each time. Cladisticanalysis simply indicates if a characterexists or not, and then determines thesequence or order in which derived char-acters arose.

A disadvantage of cladistics is that itdoes not consider the importance of anyone character. Equal weight is given to allthe characters used and some of them maybe fairly insignificant. In contrast, whenbiologists use evolutionary systematics,they weight or give more importance tosome derived characters over others. Thisis what you just did when you selected sixcharacters that you thought would be moreimportant to the survival and reproductionof pocket gophers! As another example, abiologist using evolutionary systematicsprinciples would probably consider thecharacter “giving birth to live young” more important than “fur color” whenconsidering the evolutionary relationshipsof placental mammals and monotremes(i.e. duck-billed platypus).

The branching diagram that isconstructed when a scientist usessubjective judgment when deciding whichcharacters to weight the most heavily arecalled phylogenetic trees. A phylogenetictree and a cladogram are similar in thateach represents a hypothesis of evolu-tionary history, but phylogenetic trees showboth the best judgment and the biases thatthe scientist may have.

Cladograms Based Upon DNASequences

It can be very difficult to sort outevolutionary relationships of similarspecies based on physical charactersalone. It is not always obvious which traits are the most important. Molecularbiological technologies have been veryhelpful in determining phylogeny. We cannow compare the sequences of DNA, RNAor proteins which are more representativeof fundamental genetic relationships thanare many superficial physical characters.

How are molecular cladogramsconstructed? First, the biologists need todecide which molecule to compare. Whilecladists can compare sequence portionsof cellular DNA or the mitochondrial DNA,they usually sequence ribosomal RNA(rRNA). All living cells must make proteinsand so all cells have ribosomes. The rRNAmolecule is usually not as large as theentire DNA molecule.

After DNA or rRNA sequences aredetermined for each organism, thesequences are aligned and compared.This task is usually done by computersthat can sort through the differences andconstruct cladograms. Closely relatedspecies will have fewer differences in theDNA or RNA sequences than species thatare more distantly related.

The following table shows differencesin DNA sequences for the gopher speciesat different locations for the same gene.Use this information the same way thatyou used physical characters to determinewhich hypothetical cladogram bestdescribes the most likely evolutionaryhistory for these gophers. Taking one DNAdifference at a time, place a hatch mark (/)at each position on each hypotheticalcladogram where a change or mutation



would have to occur in order to producethe four gopher species.

6. Which cladogram most likely explainsthe evolutionary relationships of thesegopher species? _____. Explain youranswer.

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7. Is it possible to have character datasupport a different hypothesis than theDNA data? _____. Explain your answer.

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I A C C G G C G C

II A T G A A C A G

III A C G G G T G C

IV G T G G A C A G

Pocket Gopher Site of DNA Change Species 1 2 3 4 5 6 7 8

Gopher DNA Sequence Differences

SPECIES

I II III IV

ANCESTOR

SPECIES

I III II IV

ANCESTOR

SPECIES

I IV II III

ANCESTOR



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8. Once the most likely cladogram hasbeen determined for related species, this information could be used to makepredictions about species. For instance, ifa disease strikes gopher species I but notgopher species III, what would you predictabout the resistance of gopher species IIand IV to this same disease?

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9. How are morphological characters andDNA sequence data related?

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10. The scientific names of the four gopherspecies are given below.

Species I—northern pocket gopher(Thomomys talpoides)

Species II—plains pocket gopher (Geomys bursarius)

Species III—Botta’s pocket gopher(Thomomys bottae)

Species IV—yellow-faced pocketgopher (Pappogeomys castanops)

What do the scientific names of thesepocket gopher species imply regardingtheir phylogenetic relationships?

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____________________________________________________________________________

11. As more DNA sequences are accu-mulated, researchers gain better under-standing of the phylogenetic relationshipsof organisms and may reassign the classification groups that organisms have previously been assigned. Whichclassification groups are more likely to bechanged, a general grouping (like kingdomor phylum), a specific grouping (like genusor species), or an intermediate grouping(like orders or families) as DNA data onspecies are evaluated?

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• Describe the application ofcladistics to a current wildlifemanagement issue.

• Review and evaluate a researchpaper and describe its signif-icance.

• Provide examples of how peerreview improves scientificinquiry.

BackgroundSpeciation occurs when a

descendant population can nolonger interbreed with theancestor population. Speciesundergo different selectivepressures in different envi-ronments. Small, isolated popu-lations of species may, over time,develop noticeably differentphysical features in response totheir environment than similarpopulations elsewhere. Are these changes indicative of asignificant modification of thespecies? Do differences inappearance indicate thepresence of a subspecies or new species? How small or bigof a change is significant. Thesequestions are important ones for biologists who are trying toquantify and maintain speciesdiversity.

Cladistics has been especiallyuseful as a tool for scientistsworking with these questions.This activity ties together all theconcepts found in The SpeciesQuestion, and demonstrateshow cladistics is used to addresscurrent wildlife issues inColorado.


Déjà Vu

SummaryStudents read and analyze a recent study completed by

the University of Colorado for the Colorado Division of Wildlifeto determine if a particular population of pocket gophers is asubspecies in need of special protection, or just a variation ofa very common species.


VocabularyCandidate species

Divergence

Genetic Drift

Home Range

Niche

Peer review

Speciation

Species of specialconcern

Subspecies

Lesson 6

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Lesson 6: Déjà Vu


• Student ReadingPages Déjà Vu—

one photocopy per student

• Access to thelibrary and the

internet

Teaching Strategies1. Thoroughly read the studentmaterials for Déjà Vu.

2. Give each student the readingpacket, Déjà Vu.

3. After giving studentssufficient time to read the packet,review the need for a legal defi-nition of species. Wildlifemanagers and others mustmake decisions and takeactions to maintain healthypopulations of organisms andtheir habitat. In order to avoidconfusion and possibly courtbattles, they need to agree onwhat populations needprotection.

4. Ask students to describe howtaxonomy and cladistic analysiscontribute to wildlife conser-vation. Cladistic analysis makesit possible to evaluate themorphological and geneticdifferences between variouswildlife populations. This helpsidentify populations that areunique and in need ofprotection.

5. Peer review is essential to theprocess of scientific inquiry. Incommunicating and defendingthe results of scientific inquiry,arguments must be logical anddemonstrate connectionsbetween the methods andprocedures used;the historicalbody ofscientific

knowledge; and the findings. The importance of peer review tothe scientific “way of knowing”can never be overemphasized.Please use this web site to showstudents examples of peerreview:

http://mountain-prairie.fws.gov/preble/PEER/PEERindex.htm

AssessmentAsk students to write a short

paper which describes therelevance of taxonomy andsystematics to wildlifemanagement.

ExtensionDivide the class into groups

of three and ask each group toreview and comment on one ofthe scientific studies concerningthe genetic uniqueness ofPreble’s meadow jumping mouseat:

http://mountain-prairie.fws.gov/preble/

Student groups should lookat the study and the peer reviewof the study. If time allows,students can debate both sides

of the Preble’s argument.


Preble’s MeadowJumping Mouse


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Key 1. To which pocket gopher species did thethree subspecies listed in the study (T.trostalis, T.t. retrosus, and T.t. macrotis)belong? Thomomys talpoides

2. The authors of the report state that thesubspecies T. t. macrotis was named onmorphological grounds. What does thatmean? Scientists based the classification ofT. t. macrotis on physical characteristicswhich could be observed.

3. When was the taxonomy of Coloradopocket gophers last revised? What new technology has been developed since thattime to assist taxonomists in determining thetaxonomy and phylogeny of pocket gophers?The taxonomy was last revised in 1915.Since then, computers and molecularbiology techniques have been developedthat allow biologists to compare DNA andRNA sequences.

4. How many mtDNA samples were taken foranalysis for the subspecies report? 24

5. Why were museum specimens used? Ifthe subspecies was indeed threatened orendangered, it would not be reasonable totrap more animals out of the population fortesting.

6. How long are the mtDNA sequences beingtested? 296 bases

7. What species was chosen to represent theout-group? Why is an out-group used? Thethirteen-lined ground squirrel was chosento represent the out-group. An out-group isnot closely related to the animals beingstudied and is used to compare thedifferences between the animals.


Lesson 6: Déjà Vu

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Caution: Much of what you are aboutto read will sound eerily familiar. You mayhave the feeling that you have read theselines before. Rest assured that nothingparanormal is happening—bits and piecesof the last five lessons are being repeatedto so that you will see the BIG PICTUREand will understand how all of these ideasconnect with wildlife conservation. TheBIG PICTURE joins together three smallerpictures from past lessons.

Small Picture #1In Lesson 1, you learned that the

Colorado Division of Wildlife (DOW) is thestate agency responsible for protectingand managing Colorado’s wildlife andhabitat. The biologists at the DOW abideby both state and federal wildlife laws.One of the most significant of all of thelaws is the Endangered Species Act (ESA)of 1973. Both the state and federalgovernment maintain a list of threatenedand endangered species and also a list ofspecies at risk of becoming threatened orendangered. At the state level, these arespecies of special concern. At thefederal level, these species are oftencandidate species for possible listing.

Species on the State of Colorado’sthreatened and endangered list aremanaged by the DOW. When a species isplaced on the federal threatened orendangered species list, the federalgovernment, through the U.S. Fish andWildlife Service, supersedes the state’sauthority to manage that species.

Wildlife on either the state or federallists requires more intensive management.Some management techniques to preventthe extinction of species or subspecieshave considerable social and economicimpacts. The ESA may limit land use orhuman activities in habitat consideredimportant to threatened or endangeredspecies. For this reason, it is importantthat listing decisions are made with thebest available scientific information.

In order to be consistent and accurate,wildlife managers use a legal definition ofspecies for decisions to list certain popu-lations as threatened or endangered. Thefour characteristics of populations thatwould be used to consider the populationunique include:1. Usually do not interbreed with otherpopulations;

2. Have different appearance, behavior,or ecological niche than other popu-lations;

3. Have notably different DNA (geneticmaterial that determines inherited char-acteristics); and

4. Represent a unique evolutionarylineage and contain the potential for aunique evolutionary future.

In Lesson 2, you discovered that twopopulations of sage grouse that biologistsonce thought belonged to the samespecies were really two different species.There was undeniable evidence that thetwo populations did not interbreed,differed in appearance, behavior andniche, and had different DNA. Lesson 2

Student Pages

Déjà Vu

Lesson 6


Lesson 6: Déjà Vu

did not address the fourth requirementthat each population represent a uniqueevolutionary lineage—this one will!

Small Picture #2In Lesson 3, you learned that ideas

and methods about classifying speciesand figuring out species relationships toone another have changed over time.Classification schemes change for anumber of reasons. First is that, over time,people develop different world views, theyhave new ideas. Some new ideas takethousands of years to develop.

A second reason taxonomic classifi-cations change is that scientists have newdata. Consider the sage grouse example.Biologists began collecting more physicaland behavioral data about the birds. Inaddition, a new technology, DNA and RNAsequencing, provided new sources ofcharacter information or data to compare.This information made it clear that the twopopulations of birds were very differentfrom each other. New informationreveals new similarities and differencesamong groups that may cause taxon-omists to revise a group’s classification.

Another reason that classificationschemes change is that biologists findnew species. Over time, humans haveexplored more of Earth’s environments.Often, unique organisms are found in deepocean vents, high alpine tundra, cavesand other newly searched places. As previously unknown species arediscovered, classifications also change toinclude them.

Small Picture #3In Lessons 4 and 5, you developed a

basic understanding of cladistics and howthis system of analysis helps biologistsunderstand the evolutionary relationshipsof all living things. Each branch of acladogram represents a unique lineage oforganisms that share unique traits or char-acters. Cladistic analysis allows wildlifebiologists to address the fourth part of thelegal species definition, that the popu-lation represent a unique evolutionarylineage and contain the potential for aunique evolutionary future.

SpeciationWhen biologists speak of a population

containing the potential for a uniqueevolutionary future, they mean that thepopulation may be genetically uniqueenough to be undergoing speciation, theprocess by which new species form.Species formation occurs in stages and isa very slow process.

Separate populations of a singlespecies can live in different types of envi-ronments. In each of these environments,there are different “selective” pressures,conditions that challenge the survival ofthe population. Often, various populationsof species overlap and interact andcontinue to exchange genes by breeding.However, some populations can becomeisolated from other populations of theirspecies. Over time, animals that are ableto survive and reproduce pass their char-acteristics to young that are geneticallybetter adapted to the unique environmentthat they live in. Genetic differencesbetween the groups accumulate slowlyover time, a process called divergence, orgenetic drift. Over time, populations of


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the same species that have notablegenetic difference because of adaptationsto certain living conditions become whatbiologists call subspecies. The membersof the newly formed subspecies havetaken the first step toward speciation.Eventually, the subspecies may becomeso different that they can no longerinterbreed successfully with other popu-lations. Biologists then consider thendifferent species.

Back To Pocket GophersPocket gophers are one group of

animals that seem particularly susceptibleto genetic drift. They have very smallhome ranges—the area where they liveand travel. Often, pocket gophers live theirentire lives in one burrow system thatoccupies less than half an acre. Pocketgophers live solitary lives, except brieflyduring the breeding season. They are veryterritorial and carefully avoid encounterswith each other. When they do meet, they fight ferociously. For these reasons,pocket gophers adapt to their local envi-ronment over many generations, and seemto diverge into subspecies and speciesmore quickly than other kinds ofmammals.

Like every wildlife species, peoplehave varying “situational” viewpointsabout pocket gophers. In their naturalenvironment, pocket gopher burrowing isviewed as beneficial. They increase soilaeration and water infiltration, and boostsoil fertility. Pocket gopher burrows alsoprovide hibernation sites and summerretreats for salamanders, frogs, and toads.

In other situations, pocket gophers areviewed as pests. Pocket gophers lovealfalfa and can be destructive to crops and

trees—girdling or clopping stems andpruning roots. They can decimate a prizedflower garden. Many homeowners andagricultural producers both past andpresent have worked on eradicatinggophers from their property.

In March of 2003, two conservationgroups filed an emergency EndangeredSpecies Act listing petition for the DouglasCounty pocket gopher (Thomomystalpoides macrotis), seeking to list thepocket gopher as endangered. Their claimwas that uncontrolled sprawl in DouglasCounty had brought the pocket gopher tothe brink of extinction, that its habitat hadbeen paved over for parking lots, car deal-erships, and other developments. Thepocket gopher of concern was thought tosurvive in only five populations in DouglasCounty.

If the pocket gopher was listed asendangered, the decision would have ahuge economic impact on DouglasCounty. As the state agency responsiblefor wildlife management, the DOW enlistedgeneticists at the University of Colorado toexplore the classification of these pocketgophers to determine if they were indeeda unique subspecies needed specialprotection. A portion of the final report ofthe scientists demonstrates the use and

importance ofcladistics inaddressing currentwildlife problems.Here is the firstsection of the report:


Lesson 6: Déjà Vu

1. To which pocket gopher species didthe three subspecies listed in the study (T.trostalis, T.t. retrosus, and T.t. macrotis)belong?

______________________________________

2. The authors of the report state that thesubspecies T. t. macrotis was named onmorphological grounds. What does thatmean?

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3. When was the taxonomy of Coloradopocket gophers last revised? What newtechnology has been developed since thattime to assist taxonomists in determiningthe taxonomy and phylogeny of pocketgophers?

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Final ReportGenetic relationships amongsubspecies of Thomomystalpoides: T. t. macrotis, T. t. rostralis, T. t. retrorsus

Jeffry B. MittonRenee CulverDepartment of Ecology and EvolutionaryBiologyUniversity of ColoradoBoulder, CO, 80309

The northern pocket gopher, Thomomystalpoides, is a polytypic species withnumerous described subspecies, nine of them within Colorado (Armstrong, 1972). T. t.macrotis is ascribed a range in Douglas,Elbert and Arapahoe Counties. Thegeographic distribution of macrotis is small,

and it is geographically isolated from T. t.rostralis, which occupies the mountains tothe west, and T. t. retrorsus, which occupiesthe Palmer Divide to the south and east.

T. t. macrotis was named on morpho-logical grounds by F. W. Miller in 1930. Thesubspecies was characterized by generallylarger size and paler, more grayish color thanadjacent populations. However, there hasbeen no taxonomic revision of Thomomystalpoides since 1915, and prior to this study,no genetic data have been collected toevaluate the phylogenetic relationshipsamong the subspecies. Human populationgrowth and development in the greaterDenver area make this a propitious time toevaluate the subspecific designation ofmacrotis. Recently, the Colorado-basedCenter for Native Ecosystems and Arizona’sForest Guardians filed a petition with the U.S. Department of the Interior to list T. t.macrotis as threatened or endangered.


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It is nearly impossibleto rely on physical traits toclassify subspecies. Inorder to have defensibleevidence to makemanagement decisionsabout T. t. macrotis, theresearchers decided that mitochondrial DNAsequencing was necessary.

We proposed to use mitochondrial DNA (mtDNA) toexamine the variation within and among these threesubspecies. Specifically, we proposed to examine thefollowing questions:

1) Is T. t. macrotis genetically distinct from T. t rostralis,and T. t. retrorsus?

2) What is the magnitude of the genetic differencesamong these subspecies?

3) Given the genetic differences among otherrecognized subspecies of the northern pocketgopher, is there sufficient justification for subspecificstatus of T. t. macrotis?


Lesson 6: Déjà Vu

Here is the procedure the researchersused:

We obtained DNA samples by clippingsmall pieces of skin from dried museumsamples. The samples were taken from the

CU’s University Museum and the DenverMuseum of Nature and Science.

Specimen sampled for a molecular systematic study of three subspecies inThomomys talpoides.

T. t.rostralis

D5833 Jefferson County, Brookvale, Evergreen D7627 Park County, 19km N, 11km E Salida; Herring Creek D9022 Park County, 1mi W of Porcupine Cave, 9100ftD9023 Park County, 1mi W of Porcupine Cave, 9100ftD10466 Jefferson County, Connifer, 10647 Snowy Trail5073 Boulder County, Long Canon, Green Mountain11376 Larimer County, Rist Canyon 17.5mi NW Ft Collins T8N, R71W, sec2613991 Clear Creek County, Headwater Clear Creek14284 Grand County, Steelman Creek

T.t.macrotisD4428 Douglas County, D'Arcy ranch; 2mi N Parker17010 Russelville Rd .5mi SE Reed Hollow17012 Douglas County, Along road to McArthur Ranch T6S, R67W, sec1917013 Douglas County, Along road to McArthur Ranch T6S, R67W, sec1917015 Douglas County, Willow Creek at County Line Rd T6S, R67W, sec417016 County Line Rd 2mi W of Willow Creek17017 Douglas County, E of Grand View Estates T6S, R67W, sec12

T.t.retrorsus17005 El Paso County, 2mi E of I-25 on Palmer Divide Rd17006 Douglas County, E of upper E Cherry Creek T10S, R65W, sec2817007 Douglas County, Palmer Gulch Rd 3.25 mi E I-25, roadside ditch17008 Douglas County, Lake Gulch T9S, R66W, sec417009 Douglas County, E of upper E Cherry Creek T10S, R65W, sec3317011 Douglas County, McMurdo Gulch Rd, .3mi W Cherry Creek T7S, R66W, sec2717019 Douglas County, E Cherry Creek T10S, R65W, sec917020 Douglas County, E Cherry Creek T10S, R65W, sec9

Note: D indicates samples from the Denver Museum of Nature and Science.

We obtained mitochondrial cytochromeoxidase I (COI) sequences from seven T. t.macrotis, nine T. t. rostralis, and eight T. t.retrorsus, and these sequences are being

submitted to GenBank. The sequences are296 base pairs long, and 40 of the nucleotidesites are variable.


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4. How many mtDNA samples were takenfor analysis for the subspecies report?

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5. Why were museum specimens used?

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6. How long are the mtDNA sequencesbeing tested?

______________________________________ Imagine the task of constructing all thepossible cladograms comparing this mayDNA sequences! This would boggle thebest of minds, so the scientists used acomputer to sort the mtDNA bases andproduce a cladogram:

A neighbor joining tree of mtDNA sequences fromThomomys talpoides rostralis, T. t. macrotis, and T. t.retrorsus, with Spermophilus tridecemlineatus as an out-group. A neighbor joining tree summarizes the rela-tionships among the 24 COI sequences, using thethirteen-lined ground squirrel as an out-group. The dataare based on 296 bases from the mitochondrial gene forcytochrome oxidase I. (Specimens marked with anasterisk might have been identified incorrectly).


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The results of the research were asfollows:

7. What species was chosen to representthe out-group? Why is an out-group used?

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The scientists found “no discernablegroups”—they did not find enough geneticdifferences to classify T.t. macrotis as a subspecies. How did their findings affect the petition to list this species asthreatened or endangered? The U.S. Fishand Wildlife Service reviewed the petitionto list the pocket gopher in DouglasCounty, Colorado, and, with this infor-mation, concluded that listing the DouglasCounty pocket gopher was not necessary.The negative finding was published in theFeb. 14, 2006; Federal Register, pages7,715–7,720 and you may read the entiredecision at this web site:

http://a257.g.akamaitech.net/7/257/2422/01jan20061800/edocket.access.gpo.gov/2006/06-1288.htm

The mtDNA sequences do not form three groups corresponding tosubspecies, but are all intermixed, with no evidence of subspecific groupsat all. That is, the mtDNA do not support the subspecific appellations in the literature. The three recognized subspecies have geographicallydistinct ranges, and differ morphologically, but their mitochondriallineages have apparently not had sufficient time for lineage sorting and/orselection to develop reciprocal monophyly.

We can now repeat the questions that we proposed to address, andprovide answers (in bold).

1) Is T. t. macrotis genetically distinct from T. t rostralis, and T. t.retrorsus?No

2) What is the magnitude of the genetic differences among thesesubspecies?There are no discernible groups, the subspecies are intermixedin the tree. There are no diagnostic differences among the threesubspecies.

3) Given the genetic differences among other recognized subspecies ofthe northern pocket gopher, is there sufficient justification forsubspecific status of T. t. macrotis?MtDNA sequences do not support the subspecific designationsof T. t. rostralis, T. t. retrorsus, and T. t. macrotis.


Lesson 6: Déjà Vu

Back to the FutureSpecies questions are important. If

species are threatened or endangered,steps must be taken to protect them. At the same time, if a population onlyappears to be unique and is not, agencieswould not want to devote scarce time andresources to management efforts for it.

Sometimes it is difficult to determinewhat the status of a particular group ofanimals is. As this booklet of lessons isbeing published, there is lots of scientificdebate about the status of a little mouse.Preble’s meadow jumping mouse (Zapushudsonius preblei) is a small rodentapproximately 9-inches in length with largehind feet adapted for jumping. Its long,bicolor tail accounts for 60 percent of itslength and it has a distinct dark stripedown the middle of its back that isbordered on either side by gray to orange-brown fur.

This shy, mostly nocturnal mouse livesin some of the most desired real estate inthe west. It prefers heavily vegetatedstreamside and adjacent upland habitatalong the foothills of the Front Range,from southeastern Wyoming south toColorado Springs, Colorado. This area hasundergone rapid residential, commercial,agricultural, and industrial development, tothe detriment of the mouse.

On May 13, 1998, Preble’s meadowjumping mouse was designated asthreatened by the U.S. Fish and WildlifeService in its entire range. Many people’slivelihoods were affected by this decisionand it was just a matter of time beforemore studies were done on the mouse.

Genetic research conducted by Dr.Rob Roy Ramey, formerly of the DenverMuseum of Nature and Science, ques-tioned the uniqueness of the mouse. On

February 2, 2005, based on Ramey’sstudy, the U.S. Fish and Wildlife Service(USFWS) issued a 12-Month Finding on a petition to delist the Preble’s andproposed to remove the mouse from theFederal list of threatened and endangeredspecies.

Seeking to use the best sciencepossible in making a final decision, theService later commissioned Dr. Tim Kingof the U.S. Geological Survey (USGS) todo an independent genetic analysis ofseveral meadow jumping mousesubspecies. The USGS study results,provided to the Service on January 25,2006, raised significant questions aboutthe conclusions drawn by Dr. Ramey in hisstudy.

Because of the complexity of thisissue, the Service extended for six monthsits proposal to delist the Preble’s meadowjumping mouse. A six-month extension inmaking final determinations on listing ordelisting proposals is allowed under theEndangered Species Act in situationswhere there is substantial disagree-ment regarding the sufficiency oraccuracy of the available data.

Since Dr. Rob Roy Ramey and Dr. TimKing disagreed on whether the Preble’smeadow jumping mouse constituted avalid subspecies, the studies were placedon the USFWS Web site for publiccomment and peer review. Peer reviewis a process of subjecting a scientist’swork or ideas to the scrutiny of otherswho are experts in the field. Peer review isan essential component of the scienceprocess, and all scientists typicallyrecognize that cherished data, analysesand interpretation may ultimately be over-turned by new information. The Servicealso convened an expert panel ofscientists to analyze, assess, and weighthe reasons why the conclusions of King


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differed from the conclusions of Ramey.All of the genetic studies, peer reviews,public comments, and results of thepanel can be found at the U.S. Fish andWildlife Service web site:

http://mountain-prairie.fws.gov/preble

You can follow the decision-makingprocess as it occurs by visiting this Web

site. What will the outcome be? Willthere be scientific consensus to make adecision? Is Preble’s meadow jumpingmouse a valid subspecies? A decisionmay be made by the time you read this,or maybe more studies will be needed.In any case, the decision about Preble’smeadow jumping mouse is sure to makea few headlines!

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Glossary

Analogous character: physical traits similarin form or function, in two or moreorganisms that are not closely related, thatevolved through convergent evolution

Ancestor: any organism, population, orspecies from which some other organism,population, or species is descended byreproduction

Ancestral character: a trait or characteristicthat many clades have in common andthat was present in an ancestor of theclades

Artiodactyls: even-toed ungulates with two orfour toes

Avian: bird

Binomial: two names, the scientific name ofan organism, the first name indicates thegenus and the second the unique speciesname

Biodiversity: biological diversity, including thevariety of species, the genetic differenceswithin species, and the variety ofecosystems.

Brachydont: low-crowned molars

Bunodont: squarish molars with low roundedcusps

Candidate species: federal designation forspecies that are at risk of becomingthreatened or endangered

Canines: dog-like species OR sharp teethused to stab and hold prey

Cannon bone: in ungulates, the 3rd and 4thmetapodials may be fused to form asingle, stronger bone

Carpal: measurement form the wrist bone ofthe wing to the tip of the longest primaryfeather

Character: identifiable feature, trait or charac-teristic

Character state: one or two or more possibleforms of a particular character or trait

Clade: a group of organisms which includesthe most recent common ancestor of all ofits members and all of the descendants ofthat most recent common ancestor, amonophyletic group

Cladist: a biologist who uses cladistics toreconstruct the common ancestry rela-tionships among organisms

Cladistics: a method of analysis that attemptsto classify organisms by common ancestry

Cladogram: a branching diagram, resultingfrom a cladistic analysis, that represents ahypothesis about the order in whichorganisms evolved

Classification system: a method of groupingorganisms

Five kingdom classification system:groups species on the basis of cellstructure, body structure, and manner ofgetting energy or nourishment into fivekingdoms—Monera, Protista, Plantae,Fungi, Animalia

Three domain classification system:groups organisms on the basis of thegenetic makeup of their ribosomal RNAinto three domains—Bacteria, Arcaea, andEukarya

Two-empire classification system:groups organisms based on cell structureinto two empires—Prokarya or Eukarya

Clone: an organism produced by asexualreproduction that is genetically identical toits parent

Convergent evolution: the independentevolution of similar structures in distantlyrelated organisms, usually because theylive in similar habitat and have a similarway of life

Culmen: straight-line measurement from thebase to the tip of the upper beak

Derived character: a unique characteristic ortrait of a particular group of organisms

Glossary


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Diastema: toothless gap between incisorsand premolars

Digits: fingers or toes

Digitigrade: a foot posture in which the digitsare in contact with the ground whenwalking or running, but not the sole orheel of the foot

Distinct Population Segment: a categoryused by the Endangered Species Act(ESA) to denote populations that must beprotected under the act; constitutes alegal definition of species

Divergence: genetic drift, genetic differencesbetween populations that accumulateslowly over time

DNA (Deoxyribonucleic Acid): the materialthat contains the information thatdetermines inherited characteristics

Endangered: at risk of becoming extinctthroughout all or a significant portion of itsrange

Endangered Species Act (ESA): a federallaw passed in 1973 that seeks to preventplants and animals from becoming extinctin the United States

Eukaryote: an organism made up of cells thathave a nucleus enclosed by a membrane

Evolutionary systematics: modifying theprocess of cladistics by placing more“weight” or importance on certain derivedcharacters

Game: wildlife species that people can legallyhunt, fish, or take

Gene: a segment of DNA that is located in achromosome and codes for a specifichereditary trait

Gene Sequencing: determining the order ofthe DNA bases in a gene

Genetic drift: divergence, genetic differencesbetween populations that accumulateslowly over time

Genus: a group of similar species

Herbivorous: eats plants

Home range: an area where an animal livesand travels in the scope of its normalactivities

Homologous characters or structures:organs and body parts which are alike instructure and origin

Hybrid: the fertile or infertile offspring ofnormally reproductively isolated popu-lations

Hypsodont: high-crowned molars

Incisors: teeth at the front of the mouth

In-group: in a cladistic analysis, the groups oforganisms which are hypothesized to beclosely related to each other

Lek: strutting grounds for breeding sagegrouse

Marine: ocean

Mesaxonic: type of foot structure where theline of symmetry passes through thecenter digit (toe), which is enlarged andbears most of the weight

Metacarpals: hand bones that connect to thefingers

Metapodials: metacarpals (hand bones) andmetatarsals (feet bones)

Metatarsals: foot bones that connect to thetoes

Molars: cheek teeth located at the rear of themouth behind the premolars

Molt: drop and replace feathers

Monophyletic group: members of a groupwhich have characteristics in commonbecause they evolved from a commonancestor

Morphological: physical form and structure

Morphological trait or character: physicalfeature of an organism

Natural selection: sometimes referred to as“survival of the fittest,” the process bywhich individuals that are better adaptedto their environment survive andreproduce more successfully than lesswell-adapted individuals and pass theirtraits to their offspring, gradually changingthe characteristics of the population


GlossaryNiche: the ecological role of an organism, the

set of resources it consumes and habitatsit occupies

Out-group: in a cladistic analysis, a groupwhich is not closely related to the groupsof organisms being studied and which isused for comparison

Reproductive isolation: populations oforganisms that cannot breed andreproduce due to some barrier or factor

Paraxonic: type of foot structure where theline of symmetry passes between the twocentermost toes, which bear the body’sweight

Parsimony: refers to a rule used to chooseamong possible cladograms, which statesthat the cladogram implying the leastnumber of changes in character states isthe best

Peer review: a process of subjecting anauthor’s scholarly work or ideas to thescrutiny of others who are experts in thefield.

Perissodactyls: odd-toed ungulates havingeither one or three weight-bearing toes

Phylogeny: an organism’s evolutionary history

Phylogenetics: the study of the pattern ofevents that have led to the distribution anddiversity of life

Phylogenetic tree: a graphical representationof the interrelationships and evolutionaryhistory of a group of organisms, whichincludes both the best judgment andbiases of the scientist

Plantigrade: a foot posture in which the fulllength of the foot, including the heel,touches the ground

Premolars: cheek teeth in front of molars

Prokaryote: an organism lacking nucleatedcells

Reproductive Isolation: barriers or factorsthat prevent one population from inter-breeding with another population

Ruminant: ungulate with a complex gutwhich helps it digest plants

Scientific name: the binomial of a species,the first name indicates the genus and thesecond the unique species name

Selection: in agriculture, a process ofchoosing animals or plants to propagate,with the result that the inherited traits ofthe chosen organisms are enhanced andperpetuated

Selenodont: molars that have hard enamelridges running from back to front

Speciation: the process by which newspecies arise

Species concept: a working definition ofspecies

Biological species concept: a group of organisms that is genetically similarenough to breed and produce viable andfertile offspring are considered a species

Ecological species concept: organismswhich occupy the same niche areconsidered a species

Isolation species concept: groups ofinterbreeding natural populations that arereproductively isolated from other suchgroups are considered a species

Morphological or Phenetic speciesconcept: organisms with the samephysical traits are considered a species

Species of special concern: Colorado’sdesignation for species that are at risk ofbecoming threatened or endangered

Stance: how an animal stands

Strata: layers of earth

Subspecies: a population of a species whosemembers have certain physical andhereditary characteristics that distinguish itfrom other populations of the species

Systematics: the field of biology that dealswith the diversity of life

Tarsals: bones in the fingers and toes

Tarsus: measurement from the point wherethe leg joins the middle toe to the first jointin the leg

Taxa: groups of organisms

Taxon: a group of organisms

Taxonomy: the science of naming and clas-sifying organisms

Terrestrial: land

Threatened: species not in immediate peril ofextinction, but likely to becomeendangered in the near future throughoutall or a significant portion of its range

Ungulate: hoofed mammal

Unguligrade: a foot posture in which ananimal walks on its tiptoes, often onhooves

Uniformitarianism: the idea that the earthwas shaped entirely by slow-movingforces acting over a very long period oftime

Wildlife: (Colorado Statutes) all non-domesticmammals, birds, fish, amphibians, reptiles,mollusks, and crustaceans

Wildlife management: the use of scientificknowledge to maintain healthy populationsof wildlife and its habitat and preservebiodiversity


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the species question - colorado parks and wildlife · 2015-02-06 · september 1, 2006 dear...

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