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Evolution:

Evolution:. Evidence of Change & How Change Occurs. Evolution. - Change over time - Process where modern organisms have descended from ancestors with modifications. Early Evolutionary Ideas. 1. Lamarck - among the first to explain how organisms change over time

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Evolution:

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  1. Evolution: Evidence of Change & How Change Occurs

  2. Evolution • - Change over time • - Process where modern organisms have descended from ancestors with modifications

  3. EarlyEvolutionaryIdeas • 1. Lamarck • - among the first to explain how organisms change over time • - later disproved

  4. Lamarck • - relied on 2 assumptions: • 1. Use and disuse • 2. Inheritance of acquired traits • - both later disproved

  5. 2. Charles Darwin (1809-1882) • - developed the theory of evolution by natural selection

  6. - traveled around the world as a naturalist (1831-1836)

  7. Galapagos wildlife

  8. Darwin’s Finches & their food Small seeds Large seeds Insects Leaves

  9. Evolution by Natural Selection • - Natural Selection is the result of 4 natural processes:

  10. 1. Natural Variation: • - all organisms produced sexually are genetically different due to gene recombination and mutations Variation in Human Height

  11. Gazelles struggling to reach food. Male caribou competing for mates. 2. Competition • - resources (food, space, water) - mates • - constant struggle for existence - winners reproduce

  12. Adaptation This natural variation may be an adaptation that helps them survive to reproduce.

  13. 3. SurvivaloftheFittest • - Those best suited will survive longer and reproduce. • - Those not suited will not survive or reproduce as often.

  14. Woodpecker

  15. 4. Heredity • - Those that survive will pass on the very traits that helped it survive.

  16. Artificial Selection • - similar to natural selection • - domestic crops and animals vary a lot

  17. Artificial Selection

  18. Artificial Selection • - only the best animals or plants are allowed to produce offspring

  19. Artificial Selection

  20. Recent Examples of Evolution

  21. 1. Peppered Moths • a. Before industrial revolution, most moths were grayish and well camouflaged.

  22. b. During the industrial revolution, soot stained the bark black. • - Rarer dark moths were then better camouflaged.

  23. - The more common light moths were easily seen and eaten. • c. Dark moths had greater fitness and became more common.

  24. 2. ResistantDiseases& Pests • a. Increased resistance to antibiotic by bacteria • b. Insects have become more resistant to pesticides

  25. Resistant Pests

  26. C. Speciation • - development of one species from another species

  27. C. Speciation Kaibab Squirrel Abert Squirrel

  28. 1. Process of Speciation • a. Separation of original population by a geographic barrier • b. Changed environment • c. Gene pool changes • d. Reproductive isolation • - two populations can no longer interbreed • e. New species arises

  29. (a) Single species; Same habitat Speciation (b) Geographical barrier; isolated populations (c) Genetic drift; tan vs white mice (d) Barrier removed; mix but don’t interbreed

  30. 2. Divergent Evolution (Adaptive Radiation) • - ancestral population evolves into several different species

  31. 2. Adaptive Radiation Hawaiian Honeycreepers

  32. 2. Adaptive Radiation

  33. 3. Convergent Evolution • - different organisms evolve similar adaptations to survive in similar niches • - develop analogous structures (similar function with different underlying anatomy)

  34. 3. Convergent Evolution

  35. 3. Convergent Evolution European Hare (lagamorph)) Patagonian “Hare” (rodent) Banded Wallaby (marsupial)

  36. 3. Convergent Evolution Tasmanian “Wolf” Coyote

  37. Placentals Marsupials Tasmanian “Wolf” Wolf Ocelot Quoll Numbat Anteater Flying Squirrel Flying Phalanger Marmot Wombat

  38. 3. Convergent Evolution American Cactus African Euphorb

  39. D. Evolutionary Theory Evolves • 1. Genetic Drift • - random changes in allele frequency produce new traits

  40. D. Evolutionary Theory Evolves • 1. Genetic Drift Masai Giraffe Rothschild Giraffe Reticulated Giraffe

  41. Chambered Nautilus Horseshoe Crab Coelacanth D. Evolutionary Theory Evolves • 2. Unchanged Gene Pools • - "living fossils": sharks, horseshoe crabs, coelacanth

  42. 3. Gradualism: • - slow change over time • 4. Punctuated Equilibrium • - periods of little change, followed by abrupt change

  43. Gradualism Punctuated Equilibrium

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