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Evolution part II
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Evolution part II


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Lecture slides for Mr. Mason's Biology I, Hon class

Lecture slides for Mr. Mason's Biology I, Hon class

Published in: Technology, Education

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  • 1. Theory of Evolution part II
  • 2. Evidence for Evolution Inferences about the history of life are based on the assumptions of certain geological principles.
  • 3. Nicolaus Steno (1638-1687) Steno's Law of Superposition
  • 4. James Hutton (1726-1797) Uniformitarianism: “ The present is the key to the past” the fundamental principle that geological processes and natural laws now operating to modify the Earth's crust have acted in much the same manner and with essentially the same intensity throughout geologic time, and that past geologic events can be explained by forces observable today;
  • 5. Charles Lyell (1797-1875) first geologic time scale proposed an older earth than was previously accepted Lyell’s text influenced Darwin’s ideas
  • 6. Relative Age generally relies on position within the geologic column in reference to index fossils. Absolute Age generally relies on the rate of decay of various radioactive isotopes.
  • 7. The amount of time it takes for 1/2 of a radioactive isotope to decay to non- radioactive form is known as half-life.
  • 8. Generalized presentation of Geologic time and the appearance of life forms.
  • 9. The Fossil Record paleontologist- scientist who study fossils Fossils are the preserved remains or traces of once living organisms the cumulative collection of fossils represents the “Fossil Record”
  • 10. The Fossil Record While there are gaps, paleontologists can offer a relatively clear picture of the evolution of many organisms. tells us of major changes in climate and geography as environments changed over earth’s history, changes in living things followed
  • 11. How fossils form frozen in ice trapped in hardened tree sap peat bogs, quicksand, tar pits most are found in sedimentary rock
  • 12. Problems in Assembling the Fossil Information all of the fossil “puzzle pieces” are not in place many organisms may live and die without leaving a trace fossil bearing rocks must be exposed to weathering
  • 13. Evidence from Living Organisms homologous structures- similar structures adapted to different environments
  • 14. Evidence from Living Organisms vestigial organs- organs or structure that seem to serve no useful purpose
  • 15. Evidence from Living Organisms Structural homologies support common descent with modifications If organisms had arisen independently, there would be very little chance of these similarities Each new species adapted what was present in the species before it.
  • 16. Evidence from Living Organisms similarities in embryo development with the passage of time, embryos become more dissimilar Biochemical similarities- DNA, ATP
  • 17. Evidence from Living Organisms Modern Synthesis Integrates the new genetics with natural selection. Ancestral relationships (phylogeny) modeled as a branching tree. Cladistics - branching tree cladagram from comparing shared characters to derived characters
  • 18. Protist Fungi Plants Archeabacteria Animals Eubacteria Common Ancestor