ecological niche

Animals arose from protozoans and initially were simply larger, more complex, and successful competitors for the same sources of food. The early animals (parazoans, coelenterates, flatworms, and extinct groups) exhibited the same basic strategies of obtaining food as did the protozoans. Because of…

This feeding niche is particularly appropriate in Northern Hemisphere forests, which include more trees with large seeds, such as the acorn-producing oaks, than do their Southern Hemisphere equivalents.