Download DARWIN`S VOYAGE

Student Resource Sheet COT - 9
DARWIN’S VOYAGE
The research you have done so far comparing natural selection and selective breeding
has been exciting. You have seen that a large variety of traits within domestic dogs
occurred because of selective breeding. There is also variety in wild canid
populations but the variations are not as different. These variations in wild canids
are the result of a process called natural selection. This process seems interesting
and you decide to investigate natural selection further. Maybe it could help you decide if the wolf
should be allowed to enter the dog show. You remember your teacher telling you about a person
named Charles Darwin and how he had developed a theory of evolution through natural selection.
You decide to go to the library and check out a book on Charles Darwin and investigate how the
process of natural selection leads to variations seen in nature.
Objective:
When you have completed this investigation, you should be able to
1. analyze Darwin’s observations of variations among similar species in order to explain how
natural selection may lead to evolution.
Activity A: Pre-Reading Activity
Darwin observed many similarities and differences among organisms in South America and
similar organisms on the Galapagos Islands. One of the organisms he investigated was the
iguana. Green iguanas live in South America in tropical rainforests near a water
source. They spend much of their time in the forest canopy eating the
fleshy leaves of trees and fresh fruit. Marine iguanas live on the
Galapagos Islands, a group of volcanic islands off the northwest coast of South
America. These iguanas can be found living among the dark volcanic boulders on the coastline
of the islands. Their primary source of food is algae that they scrape from rocks or seaweed that
grows close to the shoreline.
1. Analyze the two species of iguanas in Figure 2 on page 142 in the Prentice Hall: Science
Explorer, Cells and Heredity.
2. Identify three similarities and three differences between the green iguana and the marine iguana
using your observations of Figure 2 and your prior knowledge. Construct a T-chart in the space
below to record your similarities and differences.
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Student Resource Sheet COT - 9
3. Use the following sentence to construct a working definition of adaptation.
An adaptation of a green iguana is having a color that allows the green iguana to blend in
with its environment.
Adaptation: ________________________________________________________________
__________________________________________________________________________
4. Identify and list two features each species of iguana has which might help it to survive in its
environment. Record your observations in Chart 1, “Adaptations of the Green and Marine
Iguanas.”
CHART 1:
ADAPTATIONS OF THE GREEN AND MARINE IGUANAS
GREEN IGUANA
MARINE IGUANA
Activity B: Reading Road Map
5. Read pages 140 – 145 in Prentice Hall: Science Explorer, Cells and Heredity.
6. As you read complete the following reading road map.
Location
p. 140
Speed
START
¶1
Mission
Charles Darwin was the naturalist for the HMS Beagle.
What is a naturalist? ___________________________
READ QUICKLY,
WRITE!
p. 141-142
READ SLOWLY,
THINK!
p. 143
¶1
READ SLOWLY,
WRITE!
____________________________________________
What was Darwin’s most important observation about
species found in South America and the Galapagos
Islands?
Define adaptation: ____________________________
____________________________________________
CONTINUE…
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Student Resource Sheet COT - 9
Location
p. 143
¶1
p. 143
¶2-3
p. 143
¶3
p.144
¶2
Speed
READ
QUICKLY,
WRITE!
READ SLOWLY,
WRITE!
READ SLOWLY,
WRITE!
Mission
State an example of an adaptation of one of the
Galapagos finches.
How are adaptations related to evolution?
Define evolution: ______________________________
____________________________________________
Define natural selection: _______________________
READ SLOWLY,
WRITE!
____________________________________________
____________________________________________
p.144
¶2
p. 144
¶3
p. 145
¶1
p. 145
¶3–4
READ
QUICKLY,
WRITE!
READ SLOWLY,
THINK!
READ
QUICKLY,
WRITE!
READ SLOWLY,
WRITE!
List the factors that affect natural selection.
Why do most species produce more offspring than can
survive?
Why does competition occur within a species?
Explain how variations within a species might lead to
evolution.
STOP!
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Student Resource Sheet COT - 9
Analysis
1. Select the best response and write it on the line to the left.
_____ I. Any differences between organisms in the same species is a(n)
A adaptation.
B option.
C relationship.
D variation.
_____ II. A common defense of turtles is to pull their head and legs into their shells when
they are threatened. Snapping turtles are unable to do this, but do have a large,
sharp jaw for which they were named. How did natural selection allow for this
adaptation to occur in the snapping turtle?
A All sharp-jawed turtles were eaten because they could not pull in their legs.
B Turtles with sharp jaws were able to survive predation and reproduce.
C Turtles with sharp jaws were less attractive to look at than non-sharp jawed
turtles.
D Turtles with sharp jaws were more attractive to look at than non-sharp jawed
turtles.
`
2. Marine and green iguanas were once the same species, but are now classified as two separate
species. Review the traits of the marine and green iguana from Activity A. Use what you
have learned about natural selection and evolution to support or refute the following
statement. Choose one of the features from Activity A to support your decision.
“Over a long period of time, natural selection can lead to evolution. Helpful variations
gradually accumulate in the species, while unfavorable variations disappear.”
_____________________________________________________________________________
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Student Resource Sheet COT - 9
TAIL TALLY: Complete the concept web, “Natural Selection and
Evolution.” Describe how the theory of natural selection will help you to
prepare for your debate.
NATURAL SELECTION AND EVOLUTION
1. Place the following terms in their correct location on the concept web below using prior
knowledge.
NATURAL SELECTION, COMPETITION, VARIATION,
OVERPRODUCTION, ADAPTATION
Differences within a group
Battle over resources
More offspring than can survive
Characteristics that enable
an individual to survive
and reproduce
Only the strong survive or
survival of the fittest
Evolution
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Change in a species over
time