Download 16.2 Ideas That Shaped Darwin`s Thinking

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16.1 Darwin’s Voyage of Discovery
Observations Aboard the Beagle When Charles Darwin visited the Galápagos Islands, he discovered that similar animals
living on separate islands had different features.
Compare the diagrams of tortoises.
Isabela Island
Hood Island
tortoise
tortoise
1. The tortoises eat plants. On one island, plants grow very close to the ground. Which
island is this most likely to
be? Circle the correct answer.
Isabela Island
Hood Island
2. Why did you choose the island that you did for question 1?
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16.2 Ideas That Shaped Darwin’s Thinking
An Ancient, Changing Earth For Questions 3--6, write True if the statement is true. If the statement is false, change
the underlined word or words to make the statement true.
3. Hutton realized that Earth was much younger than previously believed.
4. Lyell thought most geological processes operated extremely quickly.
5. The processes that changed Earth in the past are different from the processes that operate in
the present.
6. Complete the table about scientists who contributed to the development of the theory of evolution.
Scientists Who Contributed to Darwin’s Theory of Evolution
Scientist
Contribution to Darwin’s Theory (how did they help Darwin?)
James Hutton
Charles Lyell
Jean-Baptiste Lamarck
Thomas Malthus
Lamarck’s Evolutionary Hypotheses -- Use the diagram to
answer Questions 8–9.
7. According to Lamarck’s hypothesis, what occurs between
steps 2 and 3 in the diagram above to make the crab’s claw
grow larger?
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8. Which step in the diagram above shows the inheritance of acquired traits as proposed by
Lamarck? ____________________________________
Population Growth For Questions 11–13, write the letter of the correct answer on the line at the left.
9. Which observation caused Thomas Malthus to form his theory about population growth?
A. Human birth rate was higher than the death rate.
B. War caused the death of thousands of people.
C. Famines were common in England in the 1800s.
D. The offspring of most species survived into adulthood.
10. Malthus’s ideas led Darwin to conclude that
A. Earth is much older than previously thought.
B. the size of the human population can grow indefinitely.
C. many more organisms are born than will survive and reproduce.
D. organisms are able to evolve through a process known as artificial selection.
16.3 Darwin Presents His Case
Evolution by Natural Selection
An adaptation is an inherited characteristic that helps an organism ____________ and ____________ in its environment.
Over time, adaptations become more and more common in the population. For example, suppose that the water in a pond
gets darker over a period of four years. The diagrams and table below show what might happen to a frog population living
in the pond.
Year 1
11. Use the diagrams below to complete the table.
Year 2
Adaptations of Frog Populations Over Time
Year
Light-Colored Frogs
1
6
Dark-Colored Frogs
Year 4
Year 3
2
3
4
Answer the questions.
12. In which year was the number of light-colored frogs greater than the number of dark-colored frogs?
13. How did the numbers of light- and dark-colored frogs change over time?
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14. Which adaptation is best suited to life in the pond in Year 3?
light coloring
15. How do the dark-colored frogs show “survival of the fittest”?
dark coloring
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16. Why is camouflage considered an adaptation?
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17. How does an animal’s level of fitness relate to its chances of survival and reproduction?
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