page 2 introduction class system national.pdf · 2015. 10. 28. · page 6page 6 6 a class system...

2

A Class SystemIntroduction

This lesson plan was developed as part of the “Darwin 2009: Exploration is Never Extinct” initiative in Pittsburgh. Darwin2009 includes a suite of lesson plans, multimedia, on-line resources and art. Find all information on-line at: www.sepa.duq.edu/darwin. This lesson plan was originally developed for the Pittsburgh Zoo & PPG Aquarium in Pittsburgh, PA.

Special Thanks to Connie George, Tracy Gray, Jennifer Hicks, Margie Marks, Dave Mintz, Kevin O’Connell, Mark Reardon

Goals

To introduce the concepts of biological classification and species.1.

To use the various animal exhibits at the zoo in order to show students 2. that animals can be classified according to common features.

To introduce Charles Darwin’s contributions to modern-day classification 3. systems.

Learning Objectives

Students will be able to define species.1.

Students will be able to distinguish how biologists in the past classified 2. organisms differently from current biologists.

Students will be able to classify objects and animals into their own 3. classification groups.

Students will analyze what similarities and differences the objects and 4. animals have.

Students will identify key characteristics of animals at the zoo.5.

Students will examine Charles Darwin’s contributions to modern-day 6. classification systems.

Materials, Resources, and Preparation

Read the introductory material provided in this packet to learn more 1. about key concepts, such as biological classification and Charles Darwin.

Make copies of “A Class System Worksheet.”2.

Gather string to use in the Pre-Visit Activity. If not using the students’ 3. shoes in the Pre-Visit Activity, gather additional items to use, such as keys, buttons, coins, paper clips, etc.

3

A Class SystemTeacher PagesVocabulary

Classification- 1. The assignment of organisms into meaningful categories to make them easier to find, study, identify, etc.

Scale of Nature- 2. A linear, hierarchical classification of animals arranged in order of complexity. Introduced by Aristotle, this biased scale has since been replaced with Darwin’s more objective phylogenetic model.

Evolution- 3. The accumulation of changes through inheritance within a population that occurs over a series of generations.

Phylogentic Model- 4. A model that classifies evolutionary relationships among a range of species by determining common ancestry.

Animal Kingdom- 5. The taxonomic group for all multi-cellular organisms that rely on other organisms for nourishment, digest food internally, and lack cell walls.

Biological Classification or Taxonomy- 6. The method by which biologists group organisms, consisting of the following categories: Kingdom, Phylum, Class, Order, Family, Genus, Species. This method takes into consideration morphological, genetic, and evolutionary similarities.

Overview

Life is diverse! How do scientists organize so much diversity?

You don’t need to go to the African Savannah or a coral reef to see that the world is full of diverse plants, animals, and microorganisms.

The first system used to organize all living organisms was called the Scale of Nature. The ancient Greek philosopher Aristotle created this system in which species were placed in order of increasing “complexity,” a very subjective characteristic. The Scale was often represented by a set of steps, with one organism placed on each step to suggest the superiority of organisms at the top and inferiority of organisms at the bottom. Similarly, humans were always placed at the top to highlight their superiority. There was no clear evidence to justify where plants and animals were placed on this scale.

Aristotle’s Scale of Nature placed humans at the top to suggest their superiority over other organisms.

Copyright 2008, all rights reserved. Visionlearning, Inc. From Charles Darwin III, http://www.visionlearning.com/library/module_viewer.php?mid=112

4

Charles Darwin, a naturalist, was one of the first scientists to question the Scale of Nature. While observing nature, he found that some groups of animals challenged the Scale. For instance, in his travels he passed by the Galapagos Islands, where he found twelve species of finches that lived on different islands but seemed very similar to each other. The similarities between the species made him think that some species were more related to each other than to all others.

Darwin hypothesized that the twelve kinds of finches all descended from one species, which had migrated amongst the various islands and changed over time into distinct species. The finches were then closely related to each other, because of their shared common ancestor. Identifying the common ancestors between different species, and discovering how all living things are connected, became the cornerstone of the principle of Evolution.

The phylogenetic model, which is used today, is a diagram that helps scientists translate how species are related by evolution. Using a tree, like the one shown here, allows for identification of the most recent common ancestor. For example, humans share a more recent common ancestor with the chimpanzee than with the gibbon!


Darwin realized that the original finch species had migrated from Equador to the Galapagos Islands. Over time the finches evolved into different species by adapting to the specific environment of each island.

5

The studies of Darwin and many other scientists form the basis for the classification system used today, called taxonomy. Taxonomy does not use complexity because there are no objective criteria to define the overall complexity of an organism. Instead, the criteria are based on morphological, evolutionary, and genetic similarities between species. These criteria categorize all living things into a series of nested groups called kingdom, phylum, class, order, family, genus, and species. A kingdom is the broadest group, such as animalia (the animal kingdom). A species is the most specific group, such as tamiasciurus hudsonicus (the American Red Squirrel).

The kingdoms are defined by some basic questions, such as: What type of cells make up the organism? How does it get the energy it needs in order to function? Is it made up of one cell or many? The answers to these questions help taxonomists place organisms into the correct kingdoms.

Dividing animals into species is more difficult, as scientists have struggled with a meaningful classification system for centuries. The modern definition of species is a group of organisms that are capable of breeding with other members of the same group but are unable to produce fertile offspring with other organisms. However, the lines between species are not concrete, and each scientist must ask questions about the organisms they are sorting in order to categorize them.

6

A Class SystemPre-VisitIntroduction

Ask students if they know why we classify things.1. Ask students if they can name a classification grouping that people 2. commonly use.Answers will vary, but can include “vegetables, parts of speech, cars, 3. etc.”Tell students what classification is (page 3).4.

Tell students that now they will do a fun activity with classification.5.

Activity

Tell each student to take off his or her shoes, or bring out items to sort.1.

Tell the students to arrange the shoes in order of complexity. 2. This will be very arbitrary. Let the students decide or even debate 3. about what it means to have a “complex” shoe.

Encourage them to question the criteria. 4.

Lecture

Tell students to think about how many different kinds of animals there 1. are. There are millions of different kinds of animals, and scientists have developed a method to classify organisms.

Tell students how scientists classified organisms in the past.2.

Tell students that before Charles Darwin, a famous biologist, scientists 3. believed that there was only one model to explain species’ relations to one another. They called this model the “Scale of Nature.” This Scale arranged all living things in order of complexity. In this model, species were permanent, and did not change over time or evolve, or become extinct.

Draw or show students that the model for the Scale of Nature looked 4. like a set of stairs, with the least complex at the bottom and the most complex at the top.

Tell students that this classification system was not useful because, just 5. like when they tried to line up their shoes in order of complexity, there was really no objective criteria as to why the shoes should be classified in a certain way - just like there was little evidence to classify animals like this.

The Scale seemed more useful to make Man seem more important than 6. other life forms!

Time: 40 minutes

Materials:

- Students’ shoes or other items- String

7

Activity - Part B.

Next, have students work as a class or in groups to develop more 1. meaningful classifications for the shoes.

Tell students to think about what the shoes have in common and what 2. makes each one unique.

Students can divide the shoes into groups of left shoes and right 3. shoes as well as into types of shoes (sandals, sneakers, etc.)

Encourage the students to think about subgroups within bigger groups. 4. At first, the groups should be large and should gradually get smaller. Eventually there should be a classification group for each shoe. For instance, there should be a group for the sneaker with shoe strings that are black. This sneaker might also be found in a larger group that contains all sneakers.

Use string to “section off” various categories.5.

Afterwards, leave the shoes in place and tell students that scientists 6. classify animals similarly.

Lecture - Part B.

Tell students that a famous scientist named Charles Darwin went on a 1. voyage around the world to the Galapagos Islands where he observed different species of birds that were very similar but lived on different islands.

Darwin could not “rank” the species in a Scale of Nature because he 2. didn’t feel that any species was better or more complex than the next one.

The wonderful variation of these birds baffled Darwin and planted the 3. idea that some of these species were more closely related than others. These finches seemed more related to each other than to other birds.

Darwin sketched the diagram to the left to express the idea that some 4. species are more closely related than others. Darwin hypothesized that these species shared a common ancestor – all these species descended from one finch species that had migrated to the various islands, and changed overtime into distinct species. This concept of common ancestor became the cornerstone of the Principle of Evolution.

Tell students that the phylogenetic model, which is used today, rather 5. than the Scale of Nature, does not assume a hierarchy of lower and higher organisms but instead focuses on the similarities, morphological and evolutionary, between species.

The important thing about this model is that it shows how all 6. living things are interconnected and does not rank any living thing as being superior or inferior, like the Scale of Nature.

Example of shoe groupings

This drawing was one of Darwin’s original sketches that he used to

determine evolutionary relationships. This idea is still the basis for today’s

phylogenetic trees.

8


Using a tree, like the one above, lets you identify the most recent 7. common ancestor. So, for example, humans share a more recent common ancestor with the chimpanzee than with the gibbon!

Tell students that they will learn more about animal classification 8. during and after their trip to the zoo.

9

A Class SystemVisitActivity

Before going on the visit to the zoo, contact the zoo to find out some 1. examples of different animals that are at the zoo. Assign each student or each group of students one of these animals. Make sure at least 10 animals are covered. (Note: A list of suggested animals can be found on the next page. An answer sheet to the questions posed on the students’ worksheet can be found on pages 12 and 13; this answer sheet uses the suggested animals listed.)

Give each student or each group of students an index card. Have the 2. students label along the side #1-8. Explain to the students that they will answer the questions from the worksheet by writing the answers they find on the index card. Questions ask about where it lives, how it travels, if it has feathers, fur, scales, etc.

Students will answer the questions on the index card and will draw 3. their animal on the opposite side of their index card.

.

Have fun at the zoo! Use the questions as a guide during your tour.4.

At the end of the visit, collect all of the index cards for classroom use.5.

Time: 120 minutes

Materials:

- Index Cards- “Do You See What I See Worksheets”- Pencils

If you can’t go to the zoo, bring the zoo to your own classroom!

- Assign each student one of the animals listed in the suggested list of animals on the next page.

- Bring in books for your students, spend a day at the library, and/or allow them to use the Internet to find information about their animal. They should write a brief report about their animal (They can write an essay or the text for an exhibit sign!) and include an illustration (They can print a picture or draw one!) of their animal.

- Hang the students’ reports and illustrations around the classroom.

- Write the name of each animal on a piece of paper and place all of these pieces in a basket or hat. Ask each student to choose a piece of paper randomly; this will be the animal that they will have to find at the “zoo.”

- During the Zoo Visit (as described to the right), the students will rotate around the room to each “exhibit.” Each student should briefly present their report when they arrive at their “exhibit.

10

Suggested List of Animals

Amur tiger

Komodo dragon

West African dwarf crocodile

Black rhino

African lion

Grant’s zebra

Ostrich

African elephant

Masai giraffe

African painted dog

Ring-tailed lemur

Mandrill

Bornean orangutan

Western lowland gorilla

Kodiak bear

Leaf-nosed bat and Jamaican fruit bat

Timber rattlesnake

Gila monster

Colorado river toad

Beaver

California sea lion

Eastern grey kangaroo

Polar bear

Northern sea otter

Bullfrog

Electric eel

Cardinal tetra

King penguin

Zebra shark

Weedy sea dragon

11

A Class SystemPost-VisitActivity

Pass out the index cards to the students. Tell them that they will 1. make their own classification groupings as a class or as smaller groups.Suggestions may include: all the animals that have feathers, all of the animals that have feathers and live in the African Savanna, etc.

Be sure the students group animals with common features. Suggest to 2. students to make groupings based on what they remember from their visit at the zoo.

After groupings are finished, ask questions to evaluate student learning, 3. such as “Why did you place this animal in this category?” or “How did the information you learned at the Zoo make your classification systems better?”

Note that the criteria the students used may not be the same criteria 4. used by scientists, but the process is very similar. Remind your students of the phylogenetic tree and modern taxonomy terms introduced earlier.

Scientists are always refining the categorization of all living things into 5. groups and sub-groups that signify meaningful relationships. All animals have been grouped into the Animal Kingdom. Explain to students that scientists have struggled with creating a meaningful classification system for centuries.

Tell students the current biological classification system groups species 6. based on their morphological similarities, much like the work done in our class today.

To improve our notion of “similarities,” scientists are also studying 7. evolutionary relationships between species (as suggested by Darwin) and, with the advent of modern biology, genetic similarities.

Review the concept of evolution if necessary.8.

Introduce the biological classification system: 9. Kingdom, Phylum, Class, Order, Family, Genus, Species

Tell students that you will show how a squirrel fits into this system as an 10. example.

A squirrel is an animal that has a backbone. It nurses its young. It has long, sharp front teeth and a bushy tail. It climbs trees, and has brown fur on its back and white fur on its underparts.

Write out the classification of a squirrel on the board:11.

Kingdom: Animalia - “animal”

Phylum: Chordata - “has a backbone”

Class: Mammalia - “nurses its young”

Time: 40 minutes

Materials:

- Index Cards- Worksheet with questions

12

Order: Rodentia - “has long, sharp front teeth”

Family: Scuridae - “has a bushy tail”

Genus: Tamiasciurus - “climbs trees”

Species: hudsonicus - “has brown fur on its back and white fur on its underparts”

Tell students that an easy way to remember the groupings is: 12.

Kings Play Cards On Flat Green Stools

Tell students that this is how a squirrel is classified and that all other 13. animals are classified similarly.

Remind students of the activities with the shoes and the classification 14. of the animal index cards. Tell students that at first they had a large grouping (like the animal kingdom), yet they were able to come up with more and more categories to sort the shoes/animals, until each one had its own category.

Be sure to make the connection between the larger grouping with 15. “kingdom” and smaller groups with smaller ranks, and how they are nested with each other. You can also identify the grouping “species” as the smallest group created by your classroom.

13

A Class SystemWorksheet

Directions:

Number 1-8 on your index card. 1.

Write the name of the animal assigned to you on your card. 2.

Answer as many questions from this worksheet as you can on your index card. 3.

After you are finished answering the questions, draw your animal on the back of the card. 4.

When you are all finished, give your index card back to your teacher.5.

Questions:

Does your animal live on land, in water, or both?1.

Does your animal have feathers, fur, or scales?2.

How does your animal travel? Does it walk, fly, swim, etc.?3.

Does your animal breathe with lungs, gills, or both?4.

Does your animal lay eggs or give live birth? 5.

Does your animal eat meat, vegetation, or both?6.

Does your animal have a backbone?7.

Does your animal have an exoskeleton?8.

Example:

14

A Class SystemAnswer Key

An

imal

Do

es y

our

anim

al liv

e o

n lan

d,

in

wat

er,

or

bo

th?

Do

es y

our

anim

al h

ave

feat

her

s,

fur,

ski

n,

or

scal

es?

Do

es it

wal

k, h

op

, cl

imb,

fly,

o

r sw

im?

Do

es y

our

anim

al

bre

athe

wit

h lun

gs,

gills,

or

bo

th?

Do

es y

our

anim

al lay

eg

gs o

r gi

ve

live

bir

th?

Do

es y

our

anim

al

eat

mea

t,

vege

table

s,

or

bo

th?

Do

es y

our

anim

al

hav

e a

bac

kbo

ne?

Do

es y

our

anim

al

hav

e an

ex

osk

el-

eto

n?

Am

ur T

iger

Land

Fur

Wal

kLu

ngs

Live

Mea

tYe

sN

o

Kom

odo

Dra

gon

Land

Scal

esW

alk

Lung

sEg

gsM

eat

Yes

No

Wes

t A

fric

an

Dw

arf

Croc

odile

Both

Scal

esW

alk/

Swim

Lung

sEg

gsM

eat

Yes

No

Blac

k Rh

ino

Land

Fur

Wal

kLu

ngs

Live

Vege

tabl

esYe

sN

o

Afr

ican

Lio

nLa

ndFu

rW

alk

Lung

sLi

veM

eat

Yes

No

Gra

nt’s

Zeb

raLa

ndFu

rW

alk

Lung

sLi

veVe

geta

bles

Yes

No

Ost

rich

Land

Feat

hers

Wal

kLu

ngs

Eggs

Both

Yes

No

Afr

ican

El

epha

ntLa

ndFu

rW

alk

Lung

sLi

veVe

geta

bles

Yes

No

Mas

ai G

iraf

feLa

ndFu

rW

alk

Lung

sLi

veVe

geta

bles

Yes

No

Afr

ican

Pain

ted

Dog

Land

Fur

Wal

kLu

ngs

Live

Mea

tYe

sN

o

Ring

Tai

led

Lem

urLa

ndFu

rW

alk/

Clim

bLu

ngs

Live

Vege

tabl

esYe

sN

o

Man

drill

Land

Fur

Wal

k/Cl

imb

Lung

sLi

veBo

thYe

sN

o

Born

ean

Ora

ngut

anLa

ndFu

rW

alk/

Clim

bLu

ngs

Live

Vege

tabl

esYe

sN

o

Wes

tern

Lo

wla

nd

Gor

illa

Land

Fur

Wal

k/Cl

imb

Lung

sLi

veVe

geta

bles

Yes

No

Kodi

ak B

ear

Land

Fur

Wal

kLu

ngs

Live

Both

Yes

No

15

An

imal

Do

es y

our

anim

al liv

e o

n lan

d,

in

wat

er,

or

bo

th?

Do

es y

our

anim

al h

ave

feat

her

s,

fur,

ski

n,

or

scal

es?

Do

es it

wal

k, h

op

, cl

imb,

fly,

o

r sw

im?

Do

es y

our

anim

al

bre

athe

wit

h lun

gs,

gills,

or

bo

th?

Do

es y

our

anim

al lay

eg

gs o

r gi

ve

live

bir

th?

Do

es y

our

anim

al

eat

mea

t,

vege

table

s,

or

bo

th?

Do

es y

our

anim

al

hav

e a

bac

kbo

ne?

Do

es y

our

anim

al

hav

e an

ex

osk

el-

eto

n?

Tim

ber

Ratt

le

Snak

eLa

ndSc

ales

Craw

lLu

ngs

Live

Mea

tYe

sN

o

Gila

Mon

ster

Land

Scal

esW

alk

Lung

sEg

gsM

eat

Yes

No

Colo

rado

Rive

r To

adBo

thSk

inW

alk/

Swim

Lung

sEg

gsM

eat

Yes

No

Beav

erBo

thFu

rW

alk/

Swim

Lung

sLi

veVe

geta

bles

Yes

No

Calif

orni

a

Se

a Li

onBo

thFu

rW

alk/

Swim

Lung

sLi

veM

eat

Yes

No

East

ern

Gre

y Ka

ngar

ooLa

ndFu

rW

alk/

Hop

Lung

sLi

veVe

geta

bles

Yes

No

Pola

r Be

arBo

thFu

rW

alk/

Swim

Lung

sLi

veBo

thYe

sN

o

Nor

ther

n

Se

a O

tter

Wat

erFu

rSw

imLu

ngs

Live

Mea

tYe

sN

o

Bull

Frog

Both

Skin

Hop

/Sw

imLu

ngs

Eggs

Mea

tYe

sN

o

Elec

tric

Eel

Wat

erSk

inW

alk

Gill

sEg

gsM

eat

Yes

No

Card

inal

Tet

raW

ater

Scal

esSw

imG

ills

Eggs

Mea

tYe

sN

o

King

Pen

guin

Both

Feat

hers

Wal

k/Sw

imLu

ngs

Eggs

Mea

tYe

sN

o

Zebr

a Sh

ark

Wat

erSc

ales

Swim

Gill

sEg

gsM

eat

Yes

No

page 2 introduction class system national.pdf · 2015. 10. 28. · page 6page 6 6 a class system...

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