Darwin and his theory of Natural Selection

1. Darwin and his theory of Natural Selection Organisms with traits well suited to the environment survive and reproduce at a greater rate than other organisms

2. 4 parts of natural selection: • 1) overproduction • 2) genetic variation • 3) struggle for survival • 4) differential reproduction

3. A moose’s nose includes a unique adaptation for underwater feeding--nostrils that close when it dips its head underwater. • *All must exist in a population in order for natural selection to act • *According to Darwin, evolution occurs by natural selection.

4. *Natural selection causes changes in the frequency of certain adaptations in a population.

5. What did Darwin mean by “Descent with Modification?” • DwM describes the process of evolution. • He meant that new forms of organisms are actually the modified descendants of older species.

6. Natural Selection • Explains how finches of the Galapagos Islands had varied beak shapes and sizes • It was based on the food they ate- like the seeds that were available

7. Fitness • An organism’s contribution to the next generation But its not just living to an old age; fit individuals have offspring that also live long enough to reproduce

8. Adaptation- • A trait that makes an individual successful • In order to be considered a favorable trait; the trait must increase the individual’s success at leaving healthy offspring

9. Section 2 Evidence of Evolution • The greatest evidence of evolution comes from … THE FOSSIL RECORD

10. As a matter of fact • Some “secrets” of evolution remain for a lack of fossil evidence

11. Relative Age Absolute Age