Question

How does a changing environment impact evolution?

Initial Model


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Claim

As the environment changes, species who can survive in the new environment will be successful and the others will not. This evolution will occur given natural selection and time.

Evidence

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source: http://www.actionbioscience.org/evolution/eldredge.html

  • this may happen relatively quickly (5-50,000 years, say) compared with the vastly longer
  • it all occurs between a species’ origin via speciation and its eventual extinction.
  • A population of the American robin, Turdus migratorius, faces a very different existence in, say, the wet woodlands of the Adirondack Mountains in the Northeastern United States, compared to what the local populations of the same species experience in Santa Fe, New Mexico.
  • Such disjunct populations encounter very different food, water availability, ambient temperatures, potential predators, and possibly even disease vectors.
  • This of course implies that natural selection (as initially seen by Sewall Wright8,9) will act very differently on such disjunct populations.
  • Many species have extensive geographic ranges similar to the American robin; it is difficult to imagine how natural selection under such circumstances can “push” an entire species into a single evolutionary direction over a long expanse of geological time.
  • Rather, the semi-separate evolutionary histories of local populations imply that no net change will accrue species-wide through geological time.
  • species arise by a process of splitting
  • this may happen relatively quickly (5-50,000 years, say) compared with the vastly longer
  • it all occurs between a species’ origin via speciation and its eventual extinction.
  • A population of the American robin, Turdus migratorius, faces a very different existence in, say, the wet woodlands of the Adirondack Mountains in the Northeastern United States, compared to what the local populations of the same species experience in Santa Fe, New Mexico.
  • Such disjunct populations encounter very different food, water availability, ambient temperatures, potential predators, and possibly even disease vectors.
  • This of course implies that natural selection (as initially seen by Sewall Wright8,9) will act very differently on such disjunct populations.
  • Many species have extensive geographic ranges similar to the American robin; it is difficult to imagine how natural selection under such circumstances can “push” an entire species into a single evolutionary direction over a long expanse of geological time.
  • Rather, the semi-separate evolutionary histories of local populations imply that no net change will accrue species-wide through geological time.
source:http://evolution.berkeley.edu/evolibrary/news/090501_climatechange
  • Canadian squirrels have evolved earlier breeding times. Squirrels with genes for earlier breeding were probably favored because this allows them to take advantage of an earlier spring and hoard more pinecones for winter survival.
    • squirrel-8867.jpg
  • A North American mosquito species has evolved to wait longer before going dormant for the winter. Mosquitoes with genes that cause them to go dormant later were probably favored because it allows the insects to gather more resources during our new, extra-long summers.

Final Model

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Reasoning

When the enviroment changes the mutation doesn't appear to save the species in most cases the species go extinct when the enviroment they are suited to change. in most cases the mutation had already arisen in the population and the species wasn't success full until the change occured. when natural selection and time play into the equation they chose the one with the mutation over the previously successful species to be successful and reproduce. Creating a newly evolved species better suited to the new enviroment where the old successful one has become extinct in that enviroment.