The Origin of Species, 1859
       "Descent with Modification"

      Understanding Evolutionary time

    Natural Selection link

      Inductive Reasoning


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Dating the Earth (lec. 6)

  1. Relative dating (stratigraphy)
    • Sediment Depth: 2250 m ÷ 0.03 mm/yr = ?
    • Sea Salt: 5x1016 tons ÷ 2.25x108 tons/yr = ?
    • Evolution: 300 traits ÷ 1 trait/106yr = ?
  2. Absolute dating (years)

  3. How old is the Earth? How old is the Universe? !
    Why is the Ocean Salty?

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Absolute dating methods


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Radiometric Dating



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Darwin and the Scientific Method ?

4 Observations & 3 Conclusions

  1. Populations have the potential to increase Exponentially

  2. Populations are usually constant in size

  3. Natural resources are limited

  4.     Conclusion #1

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Conclusion #1

Most organisms die leaving few or no offspring. There is a struggle for survival among individuals of a (interbreeding) population.

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Conclusion #2

Those organisms with favorable (heritable) variations are more likely to survive and reproduce.


Conclusion #3

Accumulation of favorable variations over many generations (population) is natural selection. vs. artifical selection: 1855-68


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  I. MODIFICATION WITH DESCENT

        observations 1-4, conclusion 1

 II. NATURAL SELECTION

        conclusions 2, 3
  SUPPORT:
    a. Fossil Record
    b. Biogeography
    c. Comparative Anatomy
    d. Comparative Embryology
    e. Molecular Biology

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Darwinian fundamentalism - Stephen J. Gould