Evidence Of Evolution


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Evidence Of Evolution

  1. 1. Evidence of Evolution The Fossil Record, Anatomy and Development, Biological Molecules
  2. 2. Fossils
  3. 3. Fossils
  4. 4. Fossils
  5. 5. Fossils
  6. 6. Fossils
  7. 7. Fossils <ul><li>What is a fossil exactly? </li></ul><ul><ul><li>Fossil : any remains, impression, or trace of a living thing of a former geologic age, as a skeleton, footprint, etc. </li></ul></ul><ul><li>How is the fossil record evidence for evolution? </li></ul><ul><ul><li>Provide actual record of Earth’s past life-forms </li></ul></ul><ul><ul><li>Shows a patern of development from early ancestors to modern descendants </li></ul></ul><ul><ul><li>Can predict intermediaries between similar living organisms </li></ul></ul>
  8. 8. Fossils <ul><li>Formation of fossils </li></ul><ul><ul><li>Many species have lived in environments were fossils do not form </li></ul></ul><ul><ul><li>Fossil formation are most likely found in wetlands, slow-moving streams, shallow seas, lakes, and near volcanoes </li></ul></ul><ul><ul><li>Chances are slim that fossilization will occur even in an area where fossils are likely to form, it could be eaten or scattered by scavengers and some bodies decay faster than others </li></ul></ul>
  9. 9. Fossils <ul><li>Although the fossil record will never be complete, it presents strong evidence that evolution has taken place </li></ul><ul><li>Paleontologists (scientists who study fossils) can date fossils accurately using radiometric dating, enabling them to arrange fossils from oldest to youngest </li></ul><ul><li>When this is done, orderly patterns of evolution can be seen </li></ul>
  10. 10. Fossils
  11. 11. Fossils
  12. 12. Anatomy and Development <ul><li>Comparisons of the anatomy of different types of organisms often reveal basic similarities in body structures even though the structure’s functions may differ between organisms </li></ul><ul><ul><li>Homologous structures : structures that share a common ancestry. </li></ul></ul>
  13. 13. Anatomy and Development <ul><li>Can be seen in the development of embryos </li></ul><ul><ul><li>At some point in development all vertebrate embryos have a tail, and buds that become limbs </li></ul></ul>
  14. 14. Anatomy and Development
  15. 16. Anatomy and Development
  16. 17. Biological Molecules <ul><li>Today with advances in bio-technology, we can test our scientific predictions </li></ul><ul><li>If species have changed over time as the fossil record indicates, then the genes that determine the species’ characteristics should also have changed by mutation and selection </li></ul>
  17. 18. Biological Molecules <ul><li>As species evolved, one change after another should have become part of their genetic instructions, therefore more and more changes in a gene’s nucleotide sequence should build up over time </li></ul>
  18. 19. Biological Molecules <ul><li>Proteins - this prediction was first tested by analyzing the amino acid sequences or similar proteins found in several species </li></ul><ul><ul><li>If evolution has taken place, the species descended from a recent common ancestor should have fewer amino acid differences between proteins than species with shared ancestory at a distant past </li></ul></ul><ul><ul><li>Comparing one human hemoglobin protein with same hemoglobin of another species reveals a predicted pattern </li></ul></ul>
  19. 20. Biological Molecules <ul><li>Nucleic Acids- nucleotide changes cause changes in amino acid sequence of protein </li></ul><ul><ul><li>Scientists evaluate number of changes and can hypothesize about how organisms are related through evolution </li></ul></ul><ul><ul><li>These relationships tend to reflect the relationships indicated by the fossil record </li></ul></ul>