"The world exists for its own sake, not for ours. Swallow that pill!" -- Edward Abbey

I. Community ecology: Niches

1. Each species has a certain set of conditions under which it will grow. These make up its niche.
   1. Competition results between members of any two populations whose niches overlap, because the two populations are using the same resources, and both are growing, as shown above.
   2. One population may drive the other to extinction. This is competitive exclusion. (Example in lecture: Gauss's experiments with two species of the protist Paramecium.
   3. On the other hand, another response to competition is resource partitioning -- organisms change over time in such a way as to share a resource and minimize niche overlap. EXAMPLE: barnacles Chthamalus and Semibalanus on a rocky shore.
   4. Difference between fundamental niche (set of conditions under which a species can grow) and realized niche (conditions under which it actually does grow).