The Galapagos Islands

1. The Galapagos Islands -Less than 1 mile off the coast of Equador • Although islands are close together habitat is very different on each. • Best resource for comparing Darwin’s new observations • New question: Could the variety of species found on each island once belonged to the same species?

2. 15-2: Other Idea’s That Shaped Darwin’s Thinking Changing Idea’s about the World • James Hutton, 1785- Earth is not just 10000 years old. • Earth has changed shape through geological forces taking place over extremely long periods of time. • Earth is millions of years old. (How old do we believe Earth to be now?) • Charles Lyell, 1833- Wrote Principles of Geology. (Darwin read his book while on the Beagle.) • Processes that changed the Earth in the past are still happening now. –Earth is still changing! • Volcanic eruptions, earthquakes, erosion, floods, etc.

3. Jean-Baptiste Lamarck, 1809 • First to recognize that living things have changed over time. He published his ideas the year Darwin was born. • Ideas: • Organisms had an innate tendency to become more complex and perfect • Organisms could continually acquire or lose characteristics to help them live more successfully • Organisms could pass desired traits on to offspring. • Lamark’s idea had many faults. Although Lamark paved the way for the work of later biologists his idea was incorrect. What was wrong with it?

4. Thomas Malthus, 1798, an economist • Noticed that birthrate exceeded death rate= population growth • If human population continued to grow we would run out of food and space • There were forces that kept such growth in check: war, famine, disease, natural disasters • Darwin thought his idea was easier to aplly to animals and plants than humans.