Birth of a theory: Charles Darwin (1809-1882) Sailed around the world 1831-1836 - PowerPoint PPT Presentation

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Birth of a theory: Charles Darwin (1809-1882) Sailed around the world 1831-1836

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Birth of a theory: Charles Darwin (1809-1882) Sailed around the world 1831-1836 What did Darwin s Travels reveal The diversity of living species was far greater ... – PowerPoint PPT presentation

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Title: Birth of a theory: Charles Darwin (1809-1882) Sailed around the world 1831-1836


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Birth of a theoryCharles Darwin (1809-1882)
Sailed around the world 1831-1836
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What did Darwins Travels reveal
  • The diversity of living species was far greater
    than anyone had previously known!!
  • These observations led him to develop the theory
    of evolution!!

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How did tortoises and birds differ among the
islands of the Galapagos?
  • Each island had its own type of tortoises and
    birds that were clearly different from other
    islands

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Galapagos Turtles
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Evolution is when organisms change over time. So,
modern organisms descended from ancient ones
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Evolution is a Theory Just like Gravity!
  • Evolution is a well supported explanation of
    phenomena that have occurred in the natural world
  • A theory in science is a well tested hypothesis,
    not just a guess

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Natural Selection
  • How does evolution work?
  • The traits that help an organism survive in a
    particular environment are selected in natural
    selection

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Natural Selection and Species Fitness
  • Overtime, natural selection results in changes in
    the inherited characteristics of a population.
  • Characteristics are passed from parents to their
    children
  • Helpful characteristics increase a species
    fitness (survival rate)

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Nature Selects the traits
  • An example of evolution is a population of deer
    that became isolated in a cold area.
  • Some of the deer had genes for thicker, warmer
    fur. These deer were more likely to survive, and
    their young with thick fur were more likely to
    survive to reproduce.
  • Adaptation is the process of inheriting
    characteristics that make an animal more likely
    to survive and reproduce in their environment.

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Nature Selects
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Summary of Darwins Theory
  1. Individuals in a population vary in each
    generation.
  2. Some of these variations are genetic, or
    inherited.
  3. More individuals are produced than live to grow
    up and reproduce themselves.
  4. Individuals with helpful traits are more likely
    to survive and reproduce, so those traits become
    more common.
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