1. 1 The Theory of Natural Selection Biology I

2. 2 I. Early Biology Scientists knew that organisms had changed Fossil evidence Age of the Earth

3. 3 Lamarck Changes from simple to complex Organisms want to adapt or change Acquired characteristics were inherited (passed on)

4. 4 Lamarck Later disproved

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6. 6 II. Darwin At 21, took a job as a naturalist on the HMS Beagle Collected specimens, took notes of different organisms

7. 7 His voyage:

8. 8 II. Darwin Sailed to Galapagos Islands All new species, but similar to those found elsewhere

9. 9 Finches most famous Had slightly different beaks from island to island Differed by their diet

10. 10 II. Darwin Darwin 22 years developing theory of natural selection Pressured into publishing by Wallace Published On the Origin of Species by Natural Selection

11. 11 III. Natural Selection 4 Requirements 1. Variation exist 2. Differential Reproduction 3. Heredity Best suited survive and reproduce 4. Lots of Time

12. 12 1. Variation Variations exist –Color, size, speed, etc. Variations are genetically linked

13. 13 2. Differential Reproduction Organisms produce more offspring than can survive –creates competition and Survival of the Fittest = Only the best are going to survive

14. 14 Heredity Beneficial variations survive, pass traits to offspring Passed through DNA

15. 15 Natural Selection Over time variations become more frequent in population Results in population being different than ancestors

16. 16 Evolution Evolution is the change in a population over time Natural Selection - Remember the Giraffe? How did it get the long neck?

17. 17 Evidence of Change Fossil Record Anatomy & Physiology Embryology Biochemistry

18. 18 Fossils Remains or traces of living organisms

19. 19 Physiology Mimicry-An adaptation Enables one species to resemble another species. Ex.-harmless species looks like a harmful one, good tasting vs. bad tasting.

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22. 22 Camouflage-An adaptation A species blends in with its environment to avoid predators. Ex.- peppered moth, leaf frog

23. 23 Anatomy- Homologous Structures Common evolutionary origin. Similar in arrangement or function or both. Example: forelimbs of a whale, a crocodile and a bird wing.

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25. 25 Anatomy- Analogous Structures No common evolutionary origin, but similar in function. Wings of a bat and wings of a butterfly.

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27. 27 Anatomy- Vestigial Structures No function now but was probably useful to an ancestor. Ex. A whale has leg bones, a snake has leg bones

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29. 29 Embryology Earliest stage of growth and development Embryos of a fish, a chicken, a pig, a cow, a rabbit, and a human are almost identical. They all have gill slits and a tail.

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31. 31 Biochemistry Comparisons of DNA and RNA Now monera (prokaryotes) is divided into two separate kingdoms based on their biochemistry.

32. 32 V. Mechanisms of Evolution Genetic Drift Gene Flow Artificial Selection Natural Selection Sexual Selection

33. 33 Genetic Drift Change in allele frequency by CHANCE

34. 34 GENE FLOW Bottleneck effect Founders effect 34

35. 35 Gene Flow Change in allele frequency as a result of MIGRATION

36. 36 Sources of Variation GENE FLOW moves genes among populations SEXUAL REPRODUCTION introduces new gene combinations Random MUTATIONS in DNA lead to the formation of new alleles (sound familiar?)

37. 37 Mutations Can be beneficial, neutral, or harmful for the organism Only mutations in gametes are inherited by offspring

38. 38 Bell: What is the difference between Analagous structures, Homologous Structures, and Vestigial Structures? What are the 4 requirements of Natural Selection? 38 AGENDA Intro to Classification Natural Selection Today Antibiotics