page 2 introduction class system national.pdf · 2015. 10. 28. · page 6page 6 6 a class system...
TRANSCRIPT
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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.
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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
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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!
Copyright 2008, all rights reserved. Visionlearning, Inc. From Charles Darwin III, http://www.visionlearning.com/library/module_viewer.php?mid=112
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.
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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.
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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
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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.
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Copyright 2008, all rights reserved. Visionlearning, Inc. From Charles Darwin III, http://www.visionlearning.com/library/module_viewer.php?mid=112
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.
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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.
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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
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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
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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.
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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:
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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
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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