Darwin

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Darwins Voyage
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Darwins Observations

• English scientist who came up with some of the
  modern theories of evolution.
• Lived 1809-1882.
• Sailed on the HMS Beagle.
• Sailed to South America and the South Pacific.

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• Darwin was amazed by the amount of diversity of
  life (variety)
• Species --- a group of similar organisms that can
  mate with each other and produce fertile
  offspring.
• Viewed many creatures on the Galapagos Islands
  (Here is where he made his major findings).

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Similarities Differences

• He saw many similarities between plants and
  animals found on the Island as he did on the
  mainland.
• Also saw many differences
• Inferred that many of these plants/animals came
  from the mainland by way of wind, or set to sea
  on a log, etc.
• Once on the Island, they reproduced.

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Adaptations

• Adaptation a trait that helps an organism to
  survive and reproduce.
• Example --- beak shape of the finches.
• Evolution --- Darwin reasoned that plants or
  animals that arrived on one of the Islands faced
  conditions that were different from those on the
  mainland.
• So he thought species changed over many
  generations became better adapted to new
  conditions.
• Evolution The gradual change in a species over
  time.

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Natural Selection

• Natural selection --- process by which
  individuals are better adapted to their
  environment are more likely to survive and
  reproduce.
• Factors that affect natural selection
• Overproduction too many organisms, not enough
  resources.
• Competition --- compete to survive
• Variations differences in individuals
• Selection helpful traits stay, bad ones leave.

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Role of Genes

• Variations can result from mutations in genes or
  from shuffling of alleles.
• Traits that are inherited can only be acted on by
  natural selection.
• How does evolution form new species?
• Isolation --- complete separation from your own
  species. Can be separated by a river, mountain,
  volcano, etc.
• Isolation causes species to create new traits.
• Continental Drift Also causes isolation