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Evolution

Evolution. Fixed Species Concept. The creator had designed each and every species for a particular purpose. Result. No evolution. Created the viewpoint that all species could be identified and named (Taxonomy). A major factor in the Linnaeus classification system. Theory.

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Evolution

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  1. Evolution

  2. Fixed Species Concept • The creator had designed each and every species for a particular purpose.

  3. Result • No evolution. • Created the viewpoint that all species could be identified and named (Taxonomy). A major factor in the Linnaeus classification system.

  4. Theory • Fossils were the remains of species lost due to catastrophe. • No new species originated; species could only be lost over time. • Result - No evolution.

  5. James Hutton • 1795 - Gradualism • Profound change is the cumulative product of slow, but continuous processes.

  6. Result • Changes on the earth were gradual, not catastrophic.

  7. 1797 - 1875. Incorporated Hutton’s gradualism into a theory called Uniformitarianism. Charles Lyell

  8. Uniformitarianism • Geological processes have operated at the same rate over the Earth’s history.

  9. Result • The Earth must be VERY old. (much older than 6000 years of the fixed species concept). • Idea that slow and subtle processes can cause substantial change.

  10. Published theory in 1809. Theory - Life changed from simple to complex over time. Jean Baptiste Lamarck

  11. Lamarck • Fossils were the remains of past life forms. • Evolution did occur.

  12. Lamarck’s Mechanisms 1. Use and Disuse - • Body parts used to survive become larger and stronger. • Body parts not used to survive deteriorate.

  13. Lamarck’s Mechanisms 2. Acquired Characteristics • Modifications acquired by use/disuse were passed on to offspring.

  14. Lamarck’s Mechanisms 3. Natural Transformation of Species ….species changed with every generation… extinction never occurred, organisms simply changed overtime.

  15. Problems with Lamarck’s Theory • No knowledge of genetics. • Acquired traits are not transmitted offspring.

  16. To Lamarck’s Credits • Did suggest correctly the role of fossils in evolution. • Did suggest that adaptation to the environment is a primary product of evolution.

  17. Father of the modern theory of evolution. Theory - Descent with Modification. Charles Darwin

  18. Darwin's Background • Trained as a Naturalist (after trying religion and medicine).

  19. Voyage of the Beagle

  20. Result • Darwin's training and travel opportunities allowed him to formulate and support his ideas on Natural Selection.

  21. Galapagos Finches

  22. Galapagos Islands

  23. Marine Iguana Tortise Unique animals

  24. Paper on Natural Selection identical to Darwin's ideas. Alfred Wallace - 1858

  25. Result - July 1, 1858 • Dual presentation of the Wallace-Darwin ideas to the Linnaean Society of London.

  26. Publication of "The Origin of Species” Darwin - 1859

  27. Comment • Darwin best remembered for the theory because of his overwhelming evidence and because he published.

  28. Darwinian View • History of life is like a tree with branches over time from a common source. • Current diversity of life is caused by the forks from common ancestors.

  29. Example

  30. “The Origin of Species” • Documented the occurrence of evolution. • Suggested that the mechanism for evolution was Natural Selection.

  31. Fact 1 - All species reproduce themselves exponentially. The Facts:

  32. Fact 2 - Most populations are normally stable in size. Fact 3 - Natural Resources are limited (finite).

  33. Inference 1 • The large number of offspring must compete for the finite resources. • Result - Most offspring die.

  34. More Facts Fact 4 - No two individuals in a population are exactly alike. Fact 5 - Variation is inheritable.

  35. Inference 2 • Those individuals whose inherited characteristics fit them best to their environment survive and reproduce.

  36. Inference 3 • Offspring inherit the favorable characteristics. Populations shift over time as the favorable characteristics accumulate.

  37. Nature • Determines which characteristics are favorable. • Determines who survives. • Result - “Natural Selection”

  38. Natural Selection in action

  39. Artificial Selection • When man determines the characteristics that survive and reproduce. • Result - the various breeds of animals and plants we’ve developed.

  40. Original Cultivars Ex - Mustard Plant

  41. Evolution Success Measured By • Survival • Reproduction • Whoever lives long enough and has kids is the “winner” in evolution.

  42. Requirements • In order for Natural Selection to work, you must have: • Long periods of time. • Variations within a population.

  43. Subtleties of Natural Selection 1. Populations are the units of Evolution. 2. Only inherited characteristics can evolve.

  44. Comment • Acquired characteristics may allow a species to evolve "outside" of Natural Selection. • Ex: culture, learning

  45. Evidences of Evolution 1. Biogeography 2. Fossils 3. Taxonomy 4. Comparative Anatomy 5. Comparative Embryology 6. Molecular Biology

  46. Biogeography • The geographical distribution of species. • Problem: • Species mixtures on islands • Marsupials in Australia

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