How long before a new environment becomes a natural environment (via evolution)?

Question

I expect the most appropriate units of time are "generations" (as opposed to, say, years). Also, it's possible my question is predicated on assumptions which are false, so feel free to disagree with the implicit assumptions in the question.

Answer 1

 

I am not sure how you are defining "natural environment."  I am also not sure I understand your question as it related to evolution.  You are right that it is more appropriate to talk about this in germs of generations.  This however can be difficult because generation times vary greatly depending upon species.  A bacterial environment for example can show rapid evolutionary change because generation times are very short.  When generations times are long, evolutionary change takes a great deal of time.  The answer really depends on how you define "environment" and how you define "natural environment."

Comments

Hi thanks for your reply. Let me try to clarify my question. You said: I am not sure how you are defining "natural environment."

My understanding is that if you find a species in an environment, you call it the "habitat" or "natural environment" of that species. If you then take members of that species into a new environment, their behavior (for example) will often be maladaptive with respect to the new environment. We explain the maladapted behavior by saying that, "Well they're not in their natural environment." However, given enough time, behavior and other phenotypes should approach near-optimality for the new conditions. At this point, the new environment has become "natural". My question is, how many generations (say) does this take? Or do you just have to take it on a case-by-case basis?