1. Theories of Evolution The Origin of Species or How we came to be

2. Jean Baptiste de Lamarck (1749-1829) French Scientist Theory of Acquired Traits-Traits arise during an organism’s lifetime as a result of experiences or behaviors which are passed to offspring

3. Example: Giraffes

4. Thomas Malthus In 1798, Malthus reasoned that if the human population grew unchecked, there wouldn’t be enough living space and food for everyone.

5. Charles Darwin At age 22, he was a naturalist on the H.M.S. Beagle (1831-1836) He collected fossils, specimens and recorded his observations

6. Darwin’s Journals

7. He observed that fossils resembled living species from the same region, and living species resembled other species from nearby regions

8. Galapagos Islands His interest in geographic distribution of species was kindled by a stop at the Galápagos Islands west of South America He hypothesized that species from South America had colonized the Galápagos and speciated (become a new species) on the islands origin of new species ~ adaptation to the environment

10. (b) Seed-eater (a) Cactus-eater(c) Insect-eater

11. Charles Darwin (1809-1882) Alfred Wallace (1823-1913) developed a theory of natural selection similar to Darwin’s

12. In 1859 Darwin published On the Origin of Species Two Theories: 1.Descent with Modification 2.Modification by Natural Selection

13. Ideas from The Origin of Species Darwin explained three observations about life: The unity of life The diversity of life The match between organisms and their environment

14. Descent with Modification

15. O.V.I.S.T. Overproduction Variation Inheritance Selection Time

16. Evolution by Natural Selection Overproduction 1.In nature, there is a tendency toward overproduction. Examples: mice, ants, fish, pine cone

17. 2. The sizes of these populations and the resources they need remain constant over time. Observation

18. Conclusion There is competition for survival and reproduction. Not all offspring survive

19. Variation All life forms vary genetically within a population. It is this genetic variation upon which selection works.

20. VARIATION

21. Inheritance Some of these variations are due to genetic differences which are inherited. Adaptations!

22. Selection Natural Selection- Individuals with favorable variations for their environment will live longer and leave more offspring than individuals with unfavorable variations.

23. Time The genetic makeup of the resulting population will change as it becomes better adapted for its environment over time.

24. Time REMEMBER: The Population (the group of the same species) will evolve, change over time CHANGE does not happen in an individual's life time, SO it is NOT the individual that evolves, but the species

25. Survival of the fittest!

26. Example of Natural Selection—Peppered Moths

27. After The Industrial Revolution