Evolution Power Point

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Evolution Power Point

  1. 1. A Change Through Time
  2. 2. What is Evolution? It’s a gradual change in a species over time.
  3. 4. Background History: Charles Darwin: Explorer on a observation trip aboard the HMS Beagle in the Galapagos Islands. He found a variety of species similar to those found in South and Central America and some completely new.
  4. 5. Darwin came up with the theory of Natural Selection Natural Selection : means that organisms with traits best suited to their environment are more likely to survive and reproduce. “ Survival of the Fittest”
  5. 7. The 4 Factors in Natural Selection <ul><li>Organisms produce more offspring than can survive. </li></ul>
  6. 8. 2. Variations are found among individuals of a species.
  7. 9. 3. Variations are passed on to offspring.
  8. 10. 4. Some variations allow members of a population to survive and reproduce better than others.
  9. 11. Over time, offspring of individuals with helpful variations make up more and more of a population.
  10. 12. Variations: an inherited trait (change in the DNA) that makes an individual different from other members of the same species. Could be color, shape, behavior or chemical makeup
  11. 13. Unit: Evolution Topic: Methods in which species evolve
  12. 14. <ul><li>Evolution can happen in two ways: </li></ul><ul><li>Gradualism - a slow steady process where you can see different forms of the new species. Minor changes happen </li></ul><ul><li>Example: horse </li></ul>
  13. 15. <ul><li>Punctuated Equilibrium - happens quickly . Sometimes intermediate species are not there. </li></ul><ul><li>Species branch off and evolve simultaneously. </li></ul><ul><li>Example: elephants </li></ul>
  14. 16. <ul><li>Branching Diagram Essential Questions: </li></ul><ul><li>Give a brief description of the evolutionary changes that occurred in the organism. </li></ul><ul><li>During which time period did the fossils differentiate into two branches? How did you know to branch off? </li></ul><ul><li>Explain how the chart illustrates both punctuated equilibrium and gradualism. </li></ul>
  15. 17. Evidence of Evolution
  16. 18. 1. Fossil Record Oldest fossils are at the bottom Newest at the top
  17. 19. 2. Homologous Structures - body parts that have the same number of bones, muscles or blood vessels.
  18. 21. 3. Vestigial Structures - a body part that doesn’t seem to have a function at this time. Example Pelvic bone in whales
  19. 22. 4. Embryology- studying organisms at the very early stages of development to see how they are the same. Show overhead
  20. 24. <ul><li>DNA - Organisms that have close relatives have similar DNA. Example: dogs are the closest relative to bears . </li></ul>

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