Unit 7-Change with Time (Evolution)

1. Unit 7-Change with Time(Evolution)

2. Evolution • Change With Time • The development of new types of organisms from pre-existing types of organisms over time

3. Diversity of life • Wide variety of living things • Estimate over 10 million species

4. Adaptation • An inherited trait that improves an organism’s chance of survival • Ex. long neck and legs of a giraffe • Coloration of a moth

5. Possible Explanations • Lamarck • Inheritance of Acquired Characteristics

6. Lamarck • Use-Disuse • structures used develop • not used disappear

7. Lamarck • Inheritance of Acquired Characteristics • Acquired characteristics- those obtained during the life of the organism- changes the body cells • THESE CANNOT BE INHERITED • Long neck of giraffe

8. Darwin-Descent With Modification • Theory of Natural Selection • Those individuals with characteristics best suited to their environment will survive the struggle for existence, those not suited will die. • “Nature selects” environment • Differences are present in a species before the change occurs

9. Darwin- Theory of Natural Selection • 4 Main Parts of Darwin’s Reasoning • 1. Overproduction- • organisms produce more offspring than can survive to maturity • 2. Genetic Variation- • individuals in a species are different from one another due to traits inherited • Ex. color, speed, strength, fur, structure

10. Darwin- Theory of Natural Selection • 3. Struggle to Survive- • Overproduction • Limited resources • Competition • Leads to a struggle for existence

11. Darwin- Theory of Natural Selection • 4. Differential Reproduction- • “Survival of the Fittest” • Only the fit survive • Those best adapted to the environment

12. Darwin- Theory of Natural Selection • Fittest- • those best adapted to the environment • Favorable traits are passed on to future generations- • since these traits are inherited and not acquired they will be passed on

13. Darwin- Theory of Natural Selection • Giraffe