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Evolution

Evolution. 1. Evolution = change in population over time A. Results in: 1. new types of organisms 2. extinction of other organisms: 99% of all types of organisms that ever lived are now extinct. B. Fact or Theory

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Evolution

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  1. Evolution

  2. 1. Evolution = change in population over time • A. Results in: • 1. new types of organisms • 2. extinction of other organisms: 99% of all types of organisms that ever lived are now extinct.

  3. B. Fact or Theory • 1. It is scientific fact that evolution has occurred through the history of life. • 2. Theory of evolution explains how evolution takes place including mechanisms and processes.

  4. II. Formation of Evolutionary Theory

  5. A. Jean Baptiste Lamark • 1. Hypothesis (1809): • a. A change in the environment causes changes in the needs of organisms living in that environment, which in turn causes changes in their behavior. • b. Altered behavior leads to greater or lesser use of a given structure or organ; use would cause the structure to increase in size over several generations, whereas disuse would cause it to shrink or even disappear. This rule Lamarck called the "First Law" in his book Philosophie zoologique.

  6. c. Lamarck's "Second Law" stated that all such changes were heritable. • 2. Flaw: Body building or Violin Virtuoso Issue: • 3. Disproved by August Weismann with mouse tail experiment. He docked the tails of mice over 22 generations without cutting any tails of new born mice.

  7. B. Darwin’s Theory = Natural Selection = living things that are best suited to their environment will survive. • 1. Darwin’s Voyage: Aboard the HMS Beagle as a naturalist. Sailed the world collecting data. Spent much time on the Galapagos Islands. Made maps, did geological studies, and studied plants and animals of different regions.

  8. 2. Darwin’s Influences: • a. Charles Lyell – geologist that reasoned that geological forces are very slow uniform processes therefore the earth must be very old. • b. Thomas Malthus – economist stated when populations exceeds its resources disasters will limit the growth of the population.

  9. 3. The Origin of Species = wrote 20 years after his voyage. Explained his theory. • a. There is variation within pollutions. • b. Some variations are favorable • c. More young are produced in each generation than can survive. • d. Those that can survive and reproduce are those with favorable variations. • e. Over enormous spans of time, small changes accumulate, and populations change.

  10. C. Stephen Jay Gould – punctuated equilibrium • 1. Interpret the gaps in the fossil record as representing times when the evolutions of species take place. • 2. Long periods of stability in species population and then a brief period of rapid genetic change.

  11. III. Changes in Living Things

  12. A. Adaptations = a trait that makes an organism better able to survive in an environment. • B. Mutations = A change in the DNA/genetic code • 1. Source of new traits that help organisms survive • 2. Natural events may be helpful, harmful, or have no effect at all. • 3. Mutations are the reason for variation

  13. IV. Evidence for Evolution

  14. A. Fossil Record • 1. Imprint of a leaf, footprint, organism trapped in ice or sap, skeleton • 2. Usually formed in sedimentary rock layers. • 3. Younger layers are those found on top of deeper older layers • 4. The number of fossil species still alive decreases as the rock age increases.

  15. B. Comparative Anatomy: Similarities in the anatomy or structure of organisms used to help determine their ancestry. • 1. Homologous structures: Characteristics that are similar because they were inherited from a common ancestor. Examples: Bones in the forelimbs of humans, bat, bird, and whale. • 2. Vestigial structures: Inherited but unused structures. Examples your appendix and tail bones, hip bones in snakes and certain whales. • 3. Analogous structures: Structures that are similar in purpose but not inherited from a common ancestor. Examples: wings in birds and butterflies.

  16. C. Comparative Embryology: Embryos of related organisms develop in very similar ways. Examples: Reptiles, birds and mammals have gill pouches at a certain stage in embryonic development.

  17. D. Comparative Biochemistry: Different species of animals have a similar chemical make up. • 1. Dependence on water • 2. all life is based on C, H2, N, O, & P • 3. The genetic code is made up of the same genetic alphabet • 4. Similarities between genes.

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