Chapter 5
Subject:
Summary
1. Two major factors affect the number of species in a community: the latitude in terrestrial communities and pollution in aquatic systems.
2. Species play different roles in a community. Native species sustain the ecosystem in which they are a part. Some nonnative species will crowd out native species. Indicator species alert us to harmful changes in the community. Keystone species play ecological roles in the specific community: they may assist in pollination help regulate populations. Foundation species affect the community’s habitat to benefit other species.
3. Species interact with each other in these different ways: interspecific competition, predation, parasitism, mutualism, and commensalism.