1. Interest Grabber A Trip Around the World
Section 15-1
A Trip Around the World
While on his voyage around the world aboard the H.M.S. Beagle, Charles Darwin spent about one month observing life on the Galápagos Islands. There, he encountered some unique animals, such as finches and tortoises.
1. On a sheet of paper, list five animals that you have encountered in the past two days.
2. How do these animals differ from the finches and tortoises of the Galápagos Islands? (Examine Figures 15–3 and 15–4 in your textbook.)
3. Propose a hypothesis to account for the differences between the animals that you observed and the finches and tortoises of the Galápagos Islands.

2. Section Outline 15–1 The Puzzle of Life’s Diversity
A. Voyage of the Beagle
B. Darwin’s Observations
1. Patterns of Diversity
2. Living Organisms and Fossils
3. The Galápagos Islands
C. The Journey Home

3. Giant Tortoises of the Galápagos Islands
Section 15-1
Pinta
Tower
Pinta Island Intermediate shell
Marchena
James
Fernandina
Santa Cruz
Isabela
Santa Fe
Hood Island
Saddle-backed shell
Floreana
Hood
Isabela Island
Dome-shaped shell

4. Figure 15–1 Darwin’s Voyage
Section 15-1

5. Interest Grabber My, How You’ve Changed!
Section 15-2
My, How You’ve Changed!
Prior to the 1800s, life scientists knew that living things changed over generations. They just didn’t know how these changes were brought about.
1. Divide a sheet of paper into two columns and title the first one Inherited Characteristics. Title the second column Acquired Characteristics. In the first column, list the characteristics that you believe you have always had. For example, you may have brown eyes or curly hair.
2. In the second column, list your acquired characteristics. For example, you may have learned how to play a musical instrument.
3. Which of the items in your lists do you think you might pass on to your children? Explain your answer.

6. Section Outline 15–2 Ideas That Shaped Darwin’s Thinking
A. An Ancient, Changing Earth
1. Hutton’s Theory of Geological Change
2. Lyell’s Principles of Geology
B. Lamarck’s Theory of Evolution
1. Tendency Toward Perfection
2. Use and Disuse
3. Inheritance of Acquired Traits
4. Evaluating Lamarck’s Theory
C. Population Growth

7. Movement of Earth’s Crust
Section 15-2
Sea level
Sea level
Sedimentary rocks form in horizontal layers.
When part of Earth’s crust is compressed, a bend in a rock forms, tilting the rock layers.
As the surface erodes due to water, wind, waves, or glaciers, the older rock surface is exposed.
New sediment is then deposited above the exposed older rock surface.

8. Figure 15–7 Lamarck’s Theory of Evolution
Section 15-2

9. Interest Grabber When Is a Flipper a Wing?
Section 15-3
When Is a Flipper a Wing?
All living things are related. Some relationships are easy to see— your pet cat may not roar like a lion, but it clearly resembles one. Other relationships are less obvious.

10. Interest Grabber continued
Section 15-3
1. On a sheet of paper, construct a table that has five columns and six rows. In the columns, write the following heads: Animal Group, Example, Legs, Fins, and Tail. Then, place the following animal groups in their own row: Mammal, Bird, Fish, Amphibian, Reptile, and Insect.
2. Give one example for each group, and then fill in the information for that example. For Legs, write in the number of legs that each animal has. Do animals with fins have legs? Do animals with wings have legs? If so, how many?
3. Can you tell from your table if a fish is more closely related to a bird or to an amphibian? Explain your answer.

11. Section Outline 15–3 Darwin Presents His Case
A. Publication of On the Origin of Species
B. Natural Variation and Artificial Selection
C. Evolution by Natural Selection
1. The Struggle for Existence
2. Survival of the Fittest
3. Descent With Modification
D. Evidence of Evolution
1. The Fossil Record
2. Geographic Distribution of Living Species
3. Homologous Body Structures
4. Similarities in Early Development
E. Summary of Darwin’s Theory

12. Concept Map Section 15-3 Evidence of Evolution includes
The fossil record
Geographic distribution of living species
Homologous body structures
Similarities in early development
which is composed of
which indicates
which implies
which implies
Physical remains of organisms
Common ancestral species
Similar genes

13. Figure 15–14 Geographic Distribution of Living Species
Section 15-3
Beaver
Beaver
Muskrat
Beaver and Muskrat
Coypu
Capybara
Coypu and Capybara
NORTH AMERICA
Muskrat
Capybara
SOUTH AMERICA
Coypu

14. Figure 15–15 Homologous Body Structures
Section 15-3
Turtle
Alligator
Bird
Mammals
Typical primitive fish