1. Darwin and Natural Selection

2. Darwin’s Observations
Darwin’s voyage provided insight on Evolution.

3. He Observed….Fossils
Fossils of extinct animals that resemble modern animals.
Fossils of sea animals high in the Andes mountains.

4. He Observed….Geologic Processes
Darwin witnessed an earthquake.
Applied: Geologic processes can add up to great changes over a long period of time.

5. He observed…..Variation
Differences in a physical trait among organisms in the same species.

6. He observed…Adaptation
A variation or characteristic that allows an organism to better survive in its environment.

7. Adaptation
Can lead to a genetic change in a population over time.

8. He observed ….Artificial selection
Humans change a species by breeding it for certain traits

9. Darwin started breeding pigeons
Heritability - the ability of a trait to be passed down.

10. Darwin proposed Natural Selection as a mechanism for evolution.

11. Natural Selection- 
organisms better adapted to their environment tend to survive and produce more offspring.

12. 4 main principles to Natural Selection:
Variation
Overproduction
Adaptation
Descent with modification

13. 1. Variation- differences among individuals are the basis for natural selection.
Ex. Some jaguars may be born with slightly larger jaws and teeth due to natural variation in the population. Some variations are heritable.

14. 2. Overproduction
A jaguar may produce many offspring, but not all of the young will survive due to competition for resources.

15. 3. Adaptation
Jaguars with larger jaws and teeth are able to eat shelled reptiles. These jaguars are likely to survive longer and leave more offspring than jaguars that can eat only mammals.

16. 4. Descent with modification
Because large teeth and jaws are heritable traits, they become more common characteristics in the population.

17. Fitness- is the measure of survival ability to produce more offspring.
Natural Selection
Fitness- is the measure of survival ability to produce more offspring.