Question

if a species is suddenly introduced into a new habitat, what might occur?

Answer 1

adaptive radiation @pineapplezz

Answer 2

which is the diversification of a group of organisms into forms filling different ecological niches.

Answer 3

There will be this pressure to survive in the new environment, and the organism will have to develop (species) characteristics that favor this. Those that adapt (have favorable genes) can reproduce, others with genes that are unsuitable for the environment do not end up surviving. In the end, the population of the species will change overtime as well as their gene pool.

Answer 4

There will be new selection pressures, which can lead to adaptation to the new habitat over time. For the species this could indeed mean adaptive radiation, as with Darwin's finches - which, in the absence of other birds, evolved to fill a number of different niches and became a number of different species in the process ( http://en.wikipedia.org/wiki/Darwin%27s_finches).