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.

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

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

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

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.

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

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.

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

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.

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.

Section Outline 15–3 Darwin Presents His Case A. Publication of On the Origin of Species B. Inherited 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 Embryology E. Summary of Darwin’s Theory F. Evolutionary Theory Since Darwin

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

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

Figure 15–15 Homologous Body Structures Section 15-3 Turtle Alligator Bird Mammal Ancient lobe-finned fish

Go Online The latest discoveries in evolution Interactive test Articles on evolution For links on evolution, go to www.SciLinks.org and enter the Web Code as follows: cbn-5151. For links on Darwin, go to www.SciLinks.org and enter the Web Code as follows: cbn-5152. For links on natural selection, go to www.SciLinks.org and enter the Web Code as follows: cbn-5153. Internet

Interest Grabber Answers 1. On a sheet of paper, list five animals that you have encountered in the past two days. Sample answers: dogs, cats, insects, snakes, birds, and so on. 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.) Students may not see a noticeable difference between birds in their area and finches. However, the land tortoises, which are very large, would be very different from any turtles that students may have on their lists. 3. Propose a hypothesis to account for the differences between the animals that you observed and the finches and tortoises of the Galápagos Islands. Sample hypothesis: Animals become well suited to their surroundings. Section 1 Answers

Interest Grabber Answers 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. Students should list traits that are genetically influenced. 2. In the second column, list your acquired characteristics. For example, you may have learned how to play a musical instrument. Remind students that many features, including skills, appearance, and athletic ability, can be changed to some degree by effort. 3. Which of the items in your lists do you think you might pass on to your children? Explain your answer. Genetically influenced traits are passed on. Some items, such as musical or athletic talent, may have both inherited and learned components. Section 2 Answers

Interest Grabber Answers 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? Fish do not have legs. Birds have two legs, while insects have six legs (three pairs). 3. Can you tell from your table if a fish is more closely related to a bird or to an amphibian? Explain your answer. It is difficult to tell from the table that a fish is more closely related to an amphibian than to a bird. Accept all reasonable explanations. Students may say that the fish is more closely related to the amphibian than to the bird because an amphibian and a fish spend time in the water. Section 3 Answers

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