Interest Grabber Section 15 1 A Trip Around

Interest Grabber 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 Section 15 -1 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 Island Tower Marchena Intermediate shell Fernandina James Santa Cruz Isabela Santa Fe Hood Island Floreana Isabela Island Dome-shaped shell Hood Saddle-backed shell

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

Interest Grabber Section 15 -2 My, How You’ve Changed! Prior to the 1800 s, 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 Section 15 -2 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

Movement of Earth’s Crust Section 15 -2 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 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 Section 15 -3 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

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 Physical remains of organisms Common ancestral species Similar genes

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

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