Human earth shapers/ETHS101/Ecology and Evolution/Response to Environmental Change

=The Four ways=

The key ideas are:


 * The "four ways" explain how species and organisms respond to environmental change


 * Species can tolerate change in situ if the change is within their niches. Species can have broad niches in one dimension but narrow niches in another, which means that a big change for one species might be small for another species. Species may also tolerate some conditions outside their niches, but only for a short period.


 * Species can move to areas with suitable habitat. Species have different capacities to disperse. Some kinds of landscape (e.g. hilly ones) can make it easier to disperse.


 * Species can evolve (adapt) to be able to tolerate the change. Evolution is slow, and the rate depends on how much genetic variation there is and some other things.


 * Species can go extinct if they can't tolerate, migrate or adapt. Chance also plays a part because species usually become rare before they go extinct.

The future of life on earth really depends on which combination of the four ways each species follows!