1. EVOLUTION Topic 18

3. Theory- explanation which has been scientifically tested and supported.
Hypothesis- a testable prediction

5. Evolution- The process by which species change over time
Present day organisms developed from earlier, distinctly different organisms.

6. Theories of Evolution
Inheritance of Acquired Traits- “use it or lose it”, Jean Baptist Lemarck
Genetic Drift- each generation is slightly different than the previous, changes occur over time

7. Inheritance of Acquired Traits

8. Theories of Evolution
Spontaneous Generation- living things come from non-living things
Gradualism- changes occur gradually over time
Punctuated Equilibrium- evolution occurs in short bursts with long periods of stability

9. Gradualism & Punctuated Equilibrium

10. Natural Selection
Selection of adaptations which are best suited for the environment, adaptations come through genetic mutations

11. Natural Selection

13. EVOLUTION ROCKS!

14. Fossils
Any record of organisms that lived in the geological past

17. Geological Time Scale Simple → Complex Marine → Land
Transitional forms of animals
Sufficient time for evolution to take place

18. Anatomical Evidence of Evolution

19. Scientists compare anatomy to understand how structures are used.
Evidence of a common ancestor.

20. Homologous Structures
Have the same, or similar, structure but not necessarily the same function.

21. Homologous

22. Analogous Structures Same function but different structure.
NOT inherited from a common ancestor.

23. Analogous

24. Vestigial Structures Appear to have no use
Remains of a structure which had a use in an ancestral species

25. Vestigial
Human Appendix

26. Human Coccyx (Tail Bone)
Vestigial
Human Coccyx (Tail Bone)

27. Vestigial
Whale Hip Bones

28. What happens to vestigial structures?
Eventually these structures may be adapted for new uses or slowly lost.

29. Comparative Biochemistry and Cytology

30. BIOCHEMISTRY
Chemical reactions which take place in living things

31. PHYSIOLOGY
How organ systems work together

32. What do ALL living things have in common?

33. What does DNA code for?
Proteins- such as hormones and enzymes

34. Comparative Biochemistry
Studying the similarities and differences in chemical reactions in living things.

36. Theory of Endosymbiosis

37. Larger cells engulfed smaller cells, then lived together- symbiotic relationship

38. Mitochondria and chloroplasts have DNA!
Both contain ribosomes!
Both reproduce independently!

39. Comparative Embryology
Embryo- an organism in the early stages of development

40. Endosymbiosis

41. NATURAL SELECTION

42. VARIATION within a species
Individuals with a population have characteristics which differ
IMAGES:

43. ARTIFICIAL SELECTION
IMAGE:

44. Natural Selection Sexual selection- choosing a mate
Becoming prey- will you be eaten?
Ability to reproduce- Will your genes be passed on?

45. SELECTION
IMAGES:

46. FITNESS Best adapted for the conditions
Not necessarily the largest or strongest
IMAGE:

47. Natural Selection Tale of the Peacock

48. ADAPTATIONS

49. Adaptation
A change that occurs in a population in response to environmental changes

50. Adaptive Radiation
A small group within a population develops its own gene pool
Certain traits become different from the original population’s traits
Then become 2 separate populations

52. Effects of Adaptive Radiation
New species are able to fill in needed roles in their environment.

53. Geographic Isolation
A population is separated from the original population.
Gene pools divide, forming new species

54. Speciation
The formation of a new species which has diverged from another

55. COMPETITION

56. Competition for…
Food
Water
Space
Nesting Sites

57. IMAGE: http://www. bbc. co

58. IMAGE: http://www.natureinstitute.org/txt/ch/moth.htm

59. IMAGE: http://www.natureinstitute.org/txt/ch/moth.htm

60. Pepper Moths

61. Extinction A species no longer exists
Unable to adapt to changes in environment
More variation within a species increases chance of survival

63. Endangered Species Likely to become extinct

64. CHARLES DARWIN

65. HMS BEAGLE

68. GALAPAGOS ISLANDS

69. Natural Selection Overproduction Competition Survival of the Fittest
Reproduction
Speciation

71. Evolution is happening NOW!

72. PESTICIDE RESISTANCE Some insects survive
Pass on genes to be resistant to pesticides

73. ANTIBIOTIC RESISTANCE
Certain strains of bacteria are resistant to antibiotics
Continue reproducing
Pass genes that resist antibiotics

74. Interactive Galapagos