1. Chapter 8
In the Beginning

2. History of Evolutionary Theory
Chapter 8B
History of Evolutionary Theory

3. I. History of Evolutionary Theory
Definitions
1. Evolution

4. Evolution
The gradual change that causes something to improve or become more complex Ex.) The evolution of a car

5. The evolution of the Ford mustang
1950
2014

6. I. History of Evolutionary Theory
Definitions
Evolution
The Theory of Evolution

7. Theory of Evolution
Used to describe the natural events that supposedly formed and changed the universe

8. I. History of Evolutionary Theory
Definitions
Evolution
The Theory of Evolution
a) Occurred by chance

9. I. History of Evolutionary Theory
Definitions
Evolution
The Theory of Evolution
Biological Evolution

10. Biological Evolution
The change of one kind of organism into another kind of organism over many generations

11. 3. Biological Evolution Requirements:
* Offspring must inherit new traits that make them different from their parents

12. 3. Biological Evolution Requirements:
* New traits must improve the offspring’s ability to survive

13. I. History of Evolutionary Theory
B. Evolutionists 1. Jean Baptiste Lamarck (early 1800’s)

14. Lamarck B. Evolutionists
Theory of inheritance of acquired characteristics
Traits caused by the organism’s environment
Loss, or addition, of features could be passed down to offspring

15. Lamarck B. Evolutionists b) Example: giraffes’ necks
c) Problem with theory: acquired traits do not change the organism’s genetic material

16. I. History of Evolutionary Theory
B. Evolutionists 1. Lamarck 2. Charles Darwin (mid 1800’s)

17. B. Evolutionists
2. Darwin a) Background * naturalist on HMS Beagle * Galapagos Islands

18. B. Evolutionists
2. Darwin a) Background * finches

19. Darwin’s Explanation

20. B. Evolutionists 2. Darwin
b) On the Origin of Species by Means of Natural Selection
* book proposing Theory of Natural Selection

21. Theory of Natural Selection (Main Points)
1. Some young will die.
2. Individuals in a species compete for things necessary for survival.
3. Some individuals compete more effectively.

22. Theory of Natural Selection (Main Points)
4. Individuals with traits who win the competition are the ones that will live and reproduce.
* Known as “survival of the fittest”

23. Theory of Natural Selection (Main Points)
5. Individuals that reproduce pass on their traits.
6. Only the organisms with the traits best suited to survive will be able to reproduce and pass on their traits.

24. 2. Darwin
c) Analysis of theory * Natural selection does not produce new genetic information. * Natural selection is more like selective breeding.

25. Selective Breeding
Man chooses organisms with desirable traits and breeds them, hoping that their offspring will have those same traits.

26. 2. Darwin
c) Analysis of theory * Descent with modification

27. Descent with modification
All life began with a single life form, followed by millions of years of natural selection.

28. 2. Darwin c) Analysis of theory * Descent with modification
- Michael Behe’s idea of “Irreducible Complexity” refutes this possibility

29. I. History of Evolutionary Theory
B. Evolutionists 1. Lamarck 2. Darwin 3. Hugo de Vries (early 1900’s)

30. B. Evolutionists 3. de Vries a) Mutation theory of evolution
* Mutations could produce the genetic changes needed for biological evolution

31. B. Evolutionists
3. de Vries b) Problems with the Mutation theory of evolution

32. Problems with the Mutation theory of evolution
Only germ mutations could contribute to biological evolution
To produce a new organism would require an impossibly large number of mutations

33. Problems with the Mutation theory of evolution
3. Most mutations have harmful effects * Loss-of-function * Evolution requires gain-of-function mutations

34. I. History of Evolutionary Theory
B. Evolutionists 1. Lamarck 2. Darwin 3. Hugo de Vries 4. Modern theories

35. 4. Modern Theories a) Mutation-selection theory * aka Neo-Darwinism
* Three main points

36. Main Points of Mutation-Selection Theory
1. Mutations supply new traits 2. Organisms produce more offspring than can survive 3. Natural selection allows only organisms with the best traits to survive

37. 4. Modern Theories b) Problems with mutation-selection theory
* Can change existing structures, but cannot explain development of structures

38. 4. Modern Theories b) Problems with mutation-selection theory
* Irreducible complexity

39. Problems with the Mutation-Selection Theory
Can change existing structures, but cannot explain development of structures
Mutations are rare
Must be germ mutations

40. Problems with the Mutation-Selection Theory
4. Must be gain-of-function mutations
5. “Good” mutations must occur repeatedly (and all over the world)

41. Problems with the Mutation-Selection Theory
6. Transitional, partially evolved organisms could not have survived (Irreducible complexity) 7. All these “Good” mutations is statistically impossible