1. Developing a Theory of Evolution Jean Baptiste de Lamarck (1744-1829) was among the first to recognize living things change over time

2. Jean Baptiste de Larmarck

3. Developing a Theory of Evolution Also called this to the attention of other scientists (Hutton & Lyell were geologists) He realized that organisms adapted to their environments Lamarck relied on three assumptions (which we now know are incorrect)

4. Developing a Theory of Evolution Assumption #1: A desire to change. Lamarck thought that organisms change because they have an inborn urge to better themselves Example- Birds had an urge to fly, and their constant efforts led to their ability to fly

5. Developing a Theory of Evolution Assumption #2 Use and Disuse. He said that organisms could alter their shape by using their bodies in new ways Example- Birds trying to use front limbs for flying…eventually the front limbs transformed into wings.

6. Developing a Theory of Evolution Assumption #3 Passing on Acquired Traits. The belief of Lamarck, and many other scientists at that time, was that acquired characteristics could be inherited Example- Figure 15-7, page 376 about front claw on Fiddler Crabs

7. Figure 15–7 Lamarck’s Theory of Evolution

8. Developing a Theory of Evolution Even though many of Lamarck’s ideas were incorrect, he did pave the way for Darwin’s theory of evolution Darwin (1809-1882) came after Lamarck (1744-1829)

9. Developing a Theory of Evolution Lamarck’s ideas may seem strange to us now, but was consistent with knowledge of that time A later understanding of genetics and heredity showed his ideas to be false

10. Developing a Theory of Evolution Let’s see what you remember! Explain how this image depicts Lamarck’s idea of evolution.

11. Developing a Theory of Evolution Scenario # 1 According to Lamarck, if a biologist removed the legs from a fruit fly, then the offspring of that fruit fly would be legless. Explain why Lamarck is wrong based on what we know today.

12. Developing a Theory of Evolution Scenario # 2 A naturally slender woman lifts weights and develops very large muscles. Her husband, who is naturally thin and weak, also lifts weights and gains more muscle mass. A. According to Larmarck, what would this couple’s children look like? B. What is wrong with this prediction? What would the child really look like? Why?