1. The Theory of Evolution
Let’s Look at What Darwin was Thinking

2. What is Evolution?
Evolution is….

3. How Long is “A Change Over Time”?
Individuals ____________ evolve.
Populations ___________ evolve.

4. Who was Darwin? Started medical school Attended seminary
Met up with a botanist; sailed on the HMS Beagle at the age of 23

5. http: Galapagos Island video
Volcanic Islands
http: Galapagos Island video

6. Darwin’s Tortoises
Why do they look different on different islands?

7. Darwin’s Finches
Why do they look different on different islands?

8. Darwin was Influenced by Others
James Hutton: Earth has to be more than just a few thousand years old!!

9. Darwin was Influenced by Others
Charles Lyell

10. Darwin was Influenced by Others
Thomas Malthus: The human race will grow faster than the supplies needed to support it

11. Darwin was Influenced by Others
Lamarck, 1809: Inheritance of Acquired Characteristics
Living organisms acquired characteristics that helped them adapt and survive.
Organisms then passed these characteristics on to the next generation

12. Lamarck’s Giraffes

13. Darwin was Influenced by Others
Alfred Wallace, 1859: Came to the same conclusions that Darwin did.

14. Darwin was Influenced by Others
Wallace studied the Malay Archipelago

15. Darwin’s “The Origin of Species”
Published in 1859
3 Important Observations
1. Members within a species vary. They are not all the same.
2. Much of this variation is inheritable.
3. There is a “struggle for existence.” More members of a species are born than can be supported by the environment.

17. Darwin’s 2 Important Conclusions
1. Because of the variations, some organisms are better able to survive to reproductive age and have offspring. (They are ‘fit.’)
2. Characteristics that make an organism “fit” will tend to accumulate over time.

18. Natural Selection
The traits being selected for contribute to an organism’s fitness in its environment
What drives natural selection?
What makes natural selection possible?

19. Evolution: Descent with Modification
Each living species has descended, with changes, from other species over time.
Darwin called this “descent with modification.” We now call it Evolution.

20. Darwin’s Realizations
All of these birds from the Galapagos were actually finches
They had all likely descended from a single species originally from Ecuador

21. Darwin’s Realizations
These similar looking animals are found in widely different locations.
It is most likely they evolved from different ancestors but accumulated similar adaptive features

22. Artificial Selection: Man’s Involvement in Evolution

23. Evidence for Evolution 1. Fossil record

24. Evidence for Evolution 2. Homologous Structures
Similar bone structure suggests a common ancestor

25. Evidence for Evolution 2. Homologous Structures
Vestigial Structures

26. Evidence for Evolution 2. Homologous Structures
Human Vestigial Structures

27. Evidence for Evolution 3. Similarities in Embryology
It is scary how much we look like other animals!
Human Embryo

28. A Summary of Darwin’s Theory
Individual organisms differs; some of these differences are inheritable.
Organisms produce more offspring than can be supported.
Organisms compete for limited resources.
Individuals best suited for their environment survive and reproduce.
Those characteristics that help an organism survive and reproduce are passed on to future generations.