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Answers to Exploration Questions: Darwin and evolution by natural selection

1. What are endemic species? Why did Darwin focus on endemic species?
Answer: Endemic species occur only in one geographic region on the planet. By focusing on endemic species, Darwin could eliminate the possibility that new species he observed had migrated from somewhere else. The processes that led to the formation of new species, had occurred in one isolated location.
2. What were the three patterns that Charles Darwin observed on his voyage that led him to accept and form his ideas of evolution?
Answer: The patterns that Darwin observed on his voyage were:
  • the “replacement” of extinct species by modern ones (as in the case of armadillos and giant sloths);
  • the “replacement” of one species by another similar species over large areas in the South American continent (as he observed with the rheas); and
  • the same geographic replacement patterns were observed on different small islands in a chain (seen in mockingbirds and tortoises).

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