1. Evolution Chapter 15
“A change over time”

2. The Theory of Evolution
Evolution literally means to change over time.
A theory is a well supported, testable explanation that observes observations from the natural world

3. Questions that evolution attempts to answer.
How do species adapt to changes in the environment?
How do new species develop?

4. Charles Darwin 1809-1882 Studied to be a doctor and a minister
1831 sailed around the world as a naturalist on the HMS Beagle

5. HMS Beagle

6. Darwin’s Voyage

7. Galapagos Islands

8. Galapagos Islands

11. 15-2 Darwin’s Influences

12. James Hutton Geologist
Proposed that the earth was millions of years old based on geologic evidence

13. Sir Charles Lyell Geologist
Proposed that geologic changes occur slowly over long periods of time.
Darwin read his book, Principles of Geology, on the Beagle

14. Jean Baptiste Lamarck French Naturalist
Published his ideas on evolution in 1809 in Philosophie zoologique

15. Lamarck’s Hypothesis
Organisms Strive for Perfection – all individuals are trying to better themselves

16. Lamarck’s Hypothesis Use and Disuse –
If an individual uses a trait it will be more useful
If an individual does not use a trait it will decrease in usefulness

17. Lamarck’s Hypothesis
Inheritance of Acquired characteristics

18. Analyzing Lamarck’s Hypothesis
There is no evidence to suggest that plants and animals are trying to improve themselves

19. Analyzing Lamarck’s Hypothesis
Use and disuse do not change all characteristics
Stretching will not make you taller
Reading will not make your eyesight better

20. Analyzing Lamarck’s Hypothesis
Acquired characteristics are not inherited
A mouse that loses its tail will still produce offspring with tails

21. Erasmus Darwin Charles Darwin’s Grandfather Physician and Scientist
'All vegetables and animals now living were originally derived from the smallest microscopic ones.'

22. Thomas Malthus – Economist Starvation War (Competition) Disease
Human Population would be limited
Starvation
War (Competition)
Disease

23. 15-3 Darwin Presents His Case

24. Alfred Wallace Developed his own theory of Natural Selection
Contacted Darwin
This caused Darwin to finally publish his theory with Wallace

25. On Origins of Species
After publishing with Wallace, Darwin submitted all of his ideas in a book titled On Origin of Species, By Means of Natural Selection in 1858

26. Artificial Selection
Darwin was influenced to believe change was possible because of the humans selecting for traits in plants and animals.

28. Darwin’s Theory
Evolution “Change” is driven by natural selection

29. Evidence for Evolution
Fossil Record
Anatomy
Development
Molecular Evidence

30. Fossil Record
Since most of the “ancestor” species are extinct, fossils are the only evidence that can be examined.
Intermediate “missing link” fossils are very informative

31. Archaeopterix A fossil of a bird like creature
Has feathers, teeth and claws in its wings

32. Whale Ancestors

33. Anatomy
Structures similarities in body structure indicates organisms are related

34. Homologous Structures
Structures that have common function and design (ancestry)

36. Vestigial Organs
Structures that have reduced size and or function

41. Developmental Evidence
Similarities in embryonic development are interpreted to mean closer relationships.

42. Developmental Evidence
Similarities in embryonic development are interpreted to mean closer relationships.

43. Molecular Evidence
Organisms are considered to be more closely related if
DNA sequences in genes are more similar
Amino acid sequences in proteins is more similar

44. Molecular Evidence
Organisms are considered to be more closely related if
DNA sequences in genes are more similar
Amino acid sequences in proteins is more similar

45. Summary of Darwin’s Theory

46. Variation There are differences within a population
Mutation and Sexual Reproduction

47. Competition for resources
Not all offspring will survive
Starvation
Overcrowding
Predation

48. Fitness
Some of the variants will have an advantage over the others, they will survive and produce more offspring

49. Reproduction and Inheritance
These advantages will be passed on to the next generations

50. Descent with Modification
Species alive today are descended with modification from ancestral species

51. Tree of Life
All species are connected on a single tree of life

52. Modern Theory
Mendel’s discoveries in genetics explained a great deal in evolution

53. Strengths of Darwin’s Theory
Many discoveries in Physics, Geology and Biology have supported and expanded Darwin’s ideas

54. Strengths of Darwin’s Theory
Many discoveries in Physics, Geology and Biology have supported and expanded Darwin’s ideas

55. Weaknesses of Darwin’s Theory
Researchers still debate how new species arise and how they become extinct.
The origin of life is still very uncertain