1. Theory of Evolution & Natural Selection

2. Theory In science, theories are statements or models that are used to support facts. Theories have some important properties: – They explain a wide variety of data and observations – They can be used to make predictions – They are not absolute, they serve as a model of understanding the world and can be changed as the world view changes

3. The theory of evolution remains one of the most useful theories in biology because it explains many questions and observations.

4. Some questions that can be answered by evolution. Why do so many different animals have the same structures, the arm bones in a human are the same bones as a flipper in a whale? Why do organisms have structures they no longer use, like the appendix in a human? Non functioning wings in penguins Why are there bones and fossil evidence of creatures that no longer exist? What happened to these creatures? Why do so many organisms' morphology and anatomy follow the same plan? Why is the sequence of DNA very similar in some groups of organisms but not in others? Why do the embryos of animals look very similar at an early stage?

5. Evolution Evolution Evolution = change over time

6. Evolution of Species The change in a population of organisms over time caused by both genetic change and environmental factors.

7. 7 History of Evolutionary Thought copyright cmassengale

8. 8 Early Ideas On Earth’s Organisms Aristotle believed species were fixed creations arranged by their complexity Idea lasted 2000 years copyright cmassengale

9. 9 Early Ideas On Earth’s Organisms Linnaeus – 1 st to group similar organisms and assign them Latin names Two word name (Genus species) Known as Binomial nomenclature copyright cmassengale

10. Lamarck Jean-Baptiste Pierre Antoine de Monet, Chevalier de la Marck (1744 - 1829), often just known as "Lamarck.” Naturalist who lived before and during Darwin’s lifetime

11. Lamarck Ideas that were proven to be untrue – Traits evolved through use or disuse (Ex. neck of giraffe, wings of a penguin) – Traits acquired over an individual's lifetime could be passed down to its offspring (Ex. Bodybuilder) Ideas that Darwin built upon – Evolutionary change takes place gradually and constantly

12. 12 Lamarck’s Theory of Evolution Jean-Baptiste Lamarck, 1809 One Of First Scientists To Understand That Change Occurs Over Time Stated that Changes Are Adaptations To Environment acquired in an organism’s lifetime and passed to offspring copyright cmassengale

13. 13 Lamarck’s Theory of Evolution Idea called Law of Use and Disuse If a body part were used, it got stronger If body part NOT used, it deteriorated copyright cmassengale

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15. 15 Lamarck’s Mistakes Lamarck Did NOT Know how traits were inherited (Traits are passed through genes) Genes Are NOT Changed By Activities In Life Change Through Mutation Occurs Before An Organism Is Born copyright cmassengale

16. 16 Lamarck’s Theory of Evolution Inheritance Of Acquired Traits – Traits Acquired During Ones Lifetime Would Be Passed To Offspring Clipped ears of dogs could be passed to offspring!

17. 17 Charles Darwin the Naturalist copyright cmassengale

18. Charles Darwin 1809 – 1882 Born in England Biologist & Naturalist Explored Galapagos Islands on the HMS Beagle Wrote On the Origin of Species

19. 19 A reconstruction of the HMS Beagle sailing off Patagonia. Darwin’s Voyage of Discovery copyright cmassengale

20. 20 Darwin Left England in 1831 Darwin returned 5 years later in 1836 copyright cmassengale

21. 21 HMS Beagle’s Voyage copyright cmassengale

22. 22 The Galapagos Islands Small Group of Islands 1000 km West of South America Very Different Climates Animals On Islands Unique Tortoises Iguanas Finches copyright cmassengale

23. Galapagos Islands Vast number of endemic species, found only on the islands endemic species

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26. 26 Darwin’s Observations & Conclusions The Struggle for Existence copyright cmassengale

27. 27 Voyage of the Beagle During His Travels, Darwin Made Numerous Observations And Collected Evidence That Led Him To Propose A Revolutionary Theory About The Way Life Changes Over Time copyright cmassengale

28. 28 Darwin’s Observations Patterns of Diversity were shown Unique Adaptations in organisms Species Not Evenly Distributed copyright cmassengale

29. Adaptation Process where a population becomes better suited to its environment This process takes place over many generations. May also refer to a feature which is especially important for an organism's survival.

30. 30 Definition Evolution is the slow, gradual change in a population of organisms over time copyright cmassengale

31. 31 Darwin’s Conclusion If there are more individuals than can be supported by the environment there will be a struggle for existence among individuals Only a fraction of the offspring survive each generation copyright cmassengale

32. 32 Darwin’s Observations Individuals of a population vary in their characteristics with no two individuals being exactly alike. Much of this variation between individuals is genetically inheritable. copyright cmassengale

33. 33 Darwin’s Conclusion Individuals who inherit characteristics most fit for their environment are likely to leave more offspring than less fit individuals Called Natural Selection copyright cmassengale

34. Natural Selection Survival of the Fittest Fitness = ability to survive Darwin’s theory that life forms better adapted to their current environment have a better chance of surviving and will pass on their traits to their offspring Natural selection -> Evolution

35. Darwin Presents His Ideas to the public

36. 36 On the Origin of Species published in 1859 copyright cmassengale

37. 37 Publication of “On The Origin of Species” Upon His Return To England, Darwin Developed His Observations Into The Theory of Evolution But He Did Not Publish For Almost 25 Years – Why? copyright cmassengale

38. 38 Publication of “On The Origin of Species” Darwin Knew That His Theory Would Be Extremely Controversial And Would Be Attacked His Theory Challenged Popular Beliefs copyright cmassengale

39. 39 Publication of “On The Origin of Species” Darwin read an Essay From Alfred Wallace – Fellow Naturalist – Independently Developed The Same Theory that species changed over time because of their struggle for existence When Darwin read Wallace’s essay, he knew he had to publish his findings copyright cmassengale

40. 5 Major of Points of Darwin’s Theory of Evolution by Natural Selection

41. 1. Populations have Variations

42. 2. Some Variations are favorable What type of finch would be most fit to live in an area with many seeds available to eat?

43. 3. More offspring are produced than survive If more offspring die than are produced this eventually will result in extinction, when a species no longer exists

44. 4. Those that survive have favorable traits (the most fit) Peppered Moths

45. 5. Populations will change over time

46. 46 Common Descent with Modification Darwin proposed that organisms descended from common ancestors Idea that organisms change with time, diverging from a common form Caused evolution of new species copyright cmassengale

47. 47 Theory of Evolution Supporting Evidence copyright cmassengale

48. 48 Evidence of Evolution Darwin Argued That Living Things Have Been Evolving On Earth For Millions of Years. Evidence For This Process Could Be Found In: – The Fossil Record – The Geographical Distribution of Living Species – Homologous Structures of Living Organisms – Similarities In Early Development copyright cmassengale

49. Evidence to Support Evolution & Natural Selection Comparative Anatomy Geology & Fossils DNA research

50. Comparative Anatomy Study of similarities and differences in the anatomy (structure) of different organisms. Indicates that various organisms share a common ancestor.

51. Homologous Structures Features of organisms that may not perform the same function but share similar anatomy.

52. 52 Homologous Structures copyright cmassengale

53. Embryology The study of developing organisms Embryo – early stages of vertebrate development

54. 54 Similarities In Early Development Embryonic Structures Of Different Species Show Significant Similarities copyright cmassengale

55. Ex. Similarities of chordates 1. Pharyngeal slits 2. Notochord 3. Dorsal, hollow nerve cord 4. Posterior elongation of body

56. 56 Evidence for Evolution - Comparative Embryology Similarities In Embryonic Development copyright cmassengale

57. Geological & Fossil Evidence By comparing layers of rock from different parts of the world, the sequence from the very earliest life to the present can be observed in fossils, in this way the fossil record shows a change from simple to complex organisms.

58. DNA evidence DNA in every organism shares the same amino acid base pairs – (A/T, C/G) Different amount of pairs Different sequence of pairs

59. Phylogenic Tree Life forms have evolved from simple organisms in oceans through amphibians to higher forms such as primates.

60. 60 Common Descent with Modification Darwin proposed that organisms descended from common ancestors Idea that organisms change with time, diverging from a common form Caused evolution of new species copyright cmassengale

61. Common Ancestor An organism or group of organisms to which two or more species can trace their history

62. Phylogenic Tree Life forms have evolved from simple organisms in oceans through amphibians to higher forms such as primates.

63. Modern Evolutionary Concepts

64. Gene Pool All of the alleles (genes) in a population of species Also called allele frequency

65. Genetic Drift Change in the frequency of alleles in a population’s gene pool through mutation, reproductive isolation, or chance

66. Mutation A change in DNA, usually results from a mistake during mitosis Can be helpful, harmful or have no effect on an organism

67. Reproductive Isolation What is Isolation? Reproductive Isolation = Processes or behaviors that prevent a species from reproducing – 3 Types

68. Temporal Isolation When timing does not allow for reproduction Ex. Winter vs. Summer Rabbits

69. Behavioral Isolation Different mating rituals

70. Geographic Isolation Organisms are separated by land or water features

71. Speciation New species can develop when part of the population becomes separated and evolves in isolation.

72. Founder Effect Loss of genetic variation that occurs when a new population is established by a very small number of individuals from a larger population.

73. Bottleneck Effect Reduction in size and genetic variation in size of a population due to natural disasters, disease or predators. Reduction in size and genetic variation in size of a population due to natural disasters, disease or predators.

74. Biodiversity Evolution & Natural Selection can lead to biodiversity Biodiversity = Variety of species living in the same habitat or environment

75. Benefits of Biodiversity Reduces competition Helps to cycle nutrients and waste Medicine & Food Industry & Leisure