PowerPoint Presentation

EcologyPopulation EcologyPart 2

This is the second portion of the Ecology unit. 12Predicting PopulationsSex and the Single Guppy

LO 1.3 The student is able to apply mathematical methods to data from a real or simulated population to predict what will happen to the population in the future. SP 2.2 The student can apply mathematical routines to quantities that describe natural phenomena

Sex and the Single Guppy can be found at the PBS website: http://www.pbs.org/wgbh/evolution/sex/guppy/index.html, youll need to have the Adobe Shockwave Plugin installed (ask the tech folks to do it if you cant). You should select two different variables Guppy Color Types and Predator Species and Numbers and run the simulation once. Then make a prediction about what would happen if you changed the guppy color and left the predator species the same. Make the changes and run the simulation. How did the simulation compare to your prediction. Repeat for the predator species (make a prediction) and then run the simulation again and analyze the results.

2Natural SelectionThis includes describing how organisms respond to the environment and how organisms are distributed.Events that occur in the framework of ecological time (minutes, months, years) translate into effects over the longer scale of evolutionary time (decades, centuries, millennia, and longer).

3LO 1.2 The student is able to evaluate evidence provided by data to qualitatively and quantitatively investigate the role of natural selection in evolution

SP 2.2 The student can apply mathematical routines to quantities that describe natural phenomena SP 5.3The student can evaluate the evidence provided by data sets in relations to a particular scientific question 3Natural Selection4

Big Idea 1: The process of evolution drives the diversity and unity of lifeEU 1. A change in the genetic makeup of a population over time is evolution LO 1.2The student is able to evaluate evidence provided by data to qualitatively and quantitatively investigate the role of natural selection in evolutionSP 2.2 The student can apply mathematical routines to quantities that describe natural phenomena SP 5.3The student can evaluate the evidence provided by data sets in relations to a particular scientific question

EK 1.A.2 Natural selection acts on phenotypic variations in populations. The environment determines what traits in a population are naturally selected.

4Natural Processes5

Big Idea 1: The process of evolution drives the diversity and unity of lifeEU 1.C Life continues to evolve within a changing environment.EU 1.D The origin of living systems is explained by natural processes.

Long before humans or organisms inhabited the earth, natural processes continually changed the environment. These natural processes caused change in the landscape of the earth as well as changes in the atmosphere and the gases and energy available to life.5Finch Beak Size or Shape6

Big Idea 1: The process of evolution drives the diversity and unity of lifeEU 1.C Life continues to evolve within a changing environment.EK 1.C.3 Populations of organisms continue to evolve.

So, lets look at Darwins famous finches and some work done by Peter and Rosemary Grant. Trees on the islands produce both small, soft seeds that are easy to eat; and large tough ones that require large beaks to crack open and eat. In 1977 the islands suffered a drastic drought, with the trees producing fewer seeds of all kinds.

Ask students: What do you think happened to the average beak size among the ground finches? Answer: large beaked birds were more successful resulting more of them surviving and reproducing so the average beak size increased significantly

Then ask: Does this mean that small beaks disappeared completely? Etc6Modes of Selection7

http://gregladen.com/blog/2007/01/the-modes-of-natural-selection/

See if students have the math capability and/or vocabulary to describe what is going on with respect to natural selection before your explain it to them.

Disruptive selection, also called diversifying selection (synonyms again!), extreme traits are favored over intermediate values. The variance of the trait increases and the population is divided into two distinct groups (statistically we call this bi-modal).

Stabilizing or ambidirectional selection, This is probably the most common mechanism of action for natural selection and reduces variance.

Directional selection a single phenotype is favored, causing continuous shift in one direction (skew). Under directional selection, the advantageous allele increases in frequency independently of its dominance relative to other alleles; that is, even if the advantageous allele is recessive., it will eventually become fixed. Directional selection occurs most often under environmental changes and when populations migrate to new areas with different environmental pressures

7Modes of Selection

Disruptive- produces a bi-modal curve as the extreme traits are favored

Stabilizing-reduces variance over time as the traits move closer to the mean

Directional-favors a phenotypic trait (selected by the environment)

This is an alternate graphic that shows the same modes of selection. 8Scenario9

These photographs show the same location on Captiva Island following Hurricane Charley.

What would happen to a population of birds who derive their diets from the tree tops? The population had a wide range of beak sizes.

What would happen to the population gene pool over time if the new environment favored smaller beaks? Over time, which beak would be most represented in the population of birds?Stripped Vegetation: On North Captiva Island, the extreme winds in Hurricane Charley's eyewall stripped the leaves from trees leaving bare limbs. This is reminiscent of the aftermath of Category-5 Hurricane Andrew in south Florida where lush vegetation was extensively removed. http://coastal.er.usgs.gov/hurricanes/charley/trees.html

LO 4.23 The student is able to construct explanations of the influence of environmental factors on the phenotype of an organism. 9Selection Diagrams10

ABCAsk students: Based on the Scenario at Captiva Island following Hurricane Charley on the previous slide, which Selection Diagram would you predict for future populations and why? Generally when you as a what question such as choose or predict, students will happily stop at the what answer. Dont allow that! Teach them that if they can say since or because (which youll have to do for them in the early stages of the school year) at the end of their what response, they need to explain WHY they made that choice or justify their choice in other words.

Answer:: Directional Selection because the environment is selecting for small beaks based on the new food source and acquisition of that source gives an animal with small beaks more free energy. 10Beak Selection After Hurricane11

Big Idea 1: The process of evolution drives the diversity and unity of lifeEU 1.C Life continues to evolve within a changing environment.EK 1.C.3 Populations of organisms continue to evolve.LO 1.25 The student is able to describe a model that represents evolution within a population.

Directional Selection: One hypothesis may be that beak size in the population over time may increase. Thus the gene pool would consist of more alleles for large beaks than smaller beaks.

So lets look at Darwins famous finches. If nothing happens (there is no disturbance for a long period of time) and the island trees grow taller and taller over thousands of years, what might happen to beak size?Does that mean that all small beaks have disappeared completely? Does that mean that small beaks could no rebound after some other natural environmental change that favors them? 11Biogeography & Distribution of SpeciesServes as a starting point to understanding limits on distribution of species

Species absentbecauseYesNoDispersallimitsdistribution?YesNoYesNoWeve done this before, but it bares repeating.

Have student propose answers to both the yes and the no parts of this flowchart as you go through the next few slides.

Yes? Area inaccessible or insufficient timeNo? Then move onto the next distribution limit which is BEHAVIORAL12Biogeography & Distribution of SpeciesServes as a starting point to understanding limits on distribution of species

Species absentbecauseYesNoDispersallimitsdistribution?Behaviorlimitsdistribution?YesNoYesNoArea inaccessibleor insufficient timeSee how their answers stack up! Then ask them to again propose answers

Yes? Habitat selectionNo? Biotic Factors such as other species, perhaps13Biogeography & Distribution of SpeciesServes as a starting point to understanding limits on distribution of species

Species absentbecauseYesNoDispersallimitsdistribution?Behaviorlimitsdistribution?Biotic factors(other species)limitdistribution?YesNoYesNoArea inaccessibleor insufficient timeHabitat selectionOnce more with feeling!

Yes? Predation, parasitism, competition or diseaseNo? Abiotic factors limit distribution, perhaps14Biogeography & Distribution of SpeciesServes as a starting point to understanding limits on distribution of species

Species absentbecauseYesNoDispersallimitsdistribution?Behaviorlimitsdistribution?Biotic factors(other species)limitdistribution?Abiotic factorslimitdistribution?YesNoYesNoArea inaccessibleor insufficient timeHabitat selectionPredation, parasitism,competition, diseaseFinally,

Yes? Chemical FactorsNo? Physical Factors15Biogeography & Distribution of SpeciesServes as a starting point to understanding limits on distribution of species

Species absentbecauseYesNoDispersallimitsdistribution?Behaviorlimitsdistribution?Biotic factors(other species)limitdistribution?Abiotic factorslimitdistribution?YesNoYesNoArea inaccessibleor insufficient timeHabitat selectionPredation, parasitism,competition, diseaseWaterOxygenSalinitypHSoil nutrients, etc.TemperatureLightSoil structureFireMoisture, etc.ChemicalfactorsPhysicalfactorsAny pertinent answers should be praised!

Suggested Simulations for students to practice with concepts within this unit of study:

Animal Behavior: http://eebweb.arizona.edu/Animal Behavior/modules.htm

Population Simulations: http://darwin.eeb.uconn.edu/simulations/simulations.html

Chi: http://ucsmp.uchicago.edu/secondary/curriculum/functions-statistics-trigonometry/demos/chi-exp/http://vassarstats.net/chi_beta.html

Phet: Biology-> Natural Selection Pinko Probability

http://highered.mcgraw-hill.com/sites/0073031208/student_view0/virtual_labs.htmlEcology & BehaviorGlobal Environment

http://onlinelabs.in/biologyChi Square: Fruit Fly Lab http://www.sciencecourseware.com/vcise/drosophila/

16Hydrangea Flower ColorHydrangea react to the environment and ultimately display their phenotype based on the pH of their soil.Hydrangea flower color is affected by light and soil pH. Soil pH exerts the main influence on which color a hydrangea plant will display.17

LO 3.19 The student is able to describe the connection between the regulation of gene expression and observed differences between individuals in a population.

LO 4.24 The student is able to predict the effects of a change in environmental factor on the genotypic expression of the phenotype.

Hydrangeas are fascinating in that, unlike most other plants, the color of their flowers can change dramatically. It would be nice if one could change the color of hydrangeas as easily as it changes in this picture. But for most of us, it is not that easy. The people who have the most control over the color of their hydrangeas are those who grow them in containers. It is much easier to control or alter the pH of the soil in a container than it is in the ground.

Only Hydrangea macrophylla or serrata species have the ability to change color based on the soil pH.There are some genetically altered cultivars that may stay pink or blue, but it is the exception rather than the rule. 17Fish And Maintaining Homeostasis In Various Water Conditions

18Fish and other aquatic animals deal with changing environments in part due to nature and in part due to human interactions.

Pressure- their bladder fills with gas to equalize internal pressureLO 2.25 The student can construct explanations based on scientific evidence that homeostatic mechanisms reflect continuity due to common ancestry and/or divergence due to adaptation in different environments.

LO 2.26 The student is able to analyze data to identify phylogenetic patterns or relationships, showing that homeostatic mechanisms reflect both continuity due to common ancestry and change due to evolution in different environments.

LO 2.27 The student is able to connect differences in the environment with the evolution of homeostatic mechanisms.

Homeostatic mechanisms: http://www.dec.ny.gov/animals/26034.html

Homeostatis in mammalshttp://www.brown.edu/Courses/BI0020_Miller/week/10/web-2/4-2-2007_10-21-10/Chapter_41/Present/Animations/41_A02/41_A02s.swf

18Biogeographic Realms

19Why do species live where they live? What factors influence dispersal patterns and ranges? Reward reasonable answers!19Introduced SpeciesWhats the big deal? These species are free from predators, parasites and pathogens that limit their populations in their native habitats.

These transplanted species disrupt their new community by preying on native organisms or outcompeting them for resources. 20

Introduced species are also called non-native or exotic species and are those that humans move intentionally or accidentally from the species native region to new geographic regions.20Guam: Brown Tree SnakeThe brown tree snake was accidentally introduced to Guam as a stowaway in military cargo from other parts of the South Pacific after World War II. Since then, 12 species of birds and 6 species of lizards the snakes ate have become extinct. Guam had no native snakes.

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Dispersal of Brown Tree SnakeAs humans have increased their control over transportation, even air transportation, transporting stowaways and introducing nonnative species continues to be a huge concern. Hawaii struggles with this more than any other state in our country.21Southern U.S.: Kudzu VineThe Asian plant Kudzu was introduced by the U.S. Dept. of Agriculture with good intentions. It was introduced from Japanese pavilion in the 1876 Centennial Exposition in Philadelphia. It was to help control erosion but has taken over large areas of the landscape in the Southern U.S.

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Kudzu is a huge concern and is spreading very rapidly!22Introduced Species23

Mr. and Mrs. C. E. Pleas meant well.23New York: European StarlingFrom the New York Times, 1990The year was 1890 when an eccentric drug manufacturer named Eugene Schieffelin entered New York City's Central Park and released some 60 European starlings he had imported from England. In 1891 he loosed 40 more. Schieffelin's motives were as romantic as they were ill fated: he hoped to introduce into North America every bird mentioned by Shakespeare.

Skylarks and song thrushes failed to thrive, but the enormity of his success with starlings continues to haunt us. This centennial year is worth observing as an object lesson in how even noble intentions can lead to disaster when humanity meddles with nature.

24In the intervening hundred plus years the starling population has grown to an estimated 150-200 million birds all across the US.

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