Bruce P. answered 12/20/17
Tutor
5.0
(310)
20+ year college biology/genetics teacher; I want you to understand.
Generally, the same thing is true for species as it is for individuals--you may receive life advice to 'carve out a unique niche for yourself". The problem with sharing/occupying the same niche as another species is that you are now in complete competition for everything you need. On the other hand, if your niche is different from that of all other species, then your only competition is others of your species (that's still a big deal--in general, when we think about 'survival of the fittest' we focus first on direct competitors of our own species--but any organism competing in the same niche can eat our dinner).
This is one reason why you often see 'adaptive radiation' on islands and similar 'virgin' environments--when a new organism arrives, there may be MANY unoccupied niches. If some of its descendants 'invade' and specialize in different niches, they are no longer competing with their own kind... they may be competing with nothing at all! Of course, their descendants will now compete with each other, and so they will become better adapted to that niche over time.
If you google "Niche differentiation" you'll see a more sophisticated presentation of some of these ideas.
J.R. S.
12/20/17