This chapter provides a detailed description of three basic population
interactions in ecology: predation, competition and mutualism. The per capita rate at
which a predator depletes population of its prey is known as functional response of the
predator. The issue of prey–dependent vs. predator–dependent functional response is
discussed in detail. The prey–dependent functional responses are presented in such a
way that it becomes easy to work out how a given functional response is related to any
other. How competitive exclusion principle work is demonstrated with the help of
isoclines. A lucid description of relatively difficult and subtle interactions such as
apparent competition and competitive displacement are presented. At the end, the
chapter briefly describes two kinds of mutualistic interactions: Symbiotic mutualism and
Non-symbiotic mutualism.
Keywords: Populations, Trophic interactions, Predation, functional responses,
Prey–dependent, Predator–dependent, Competition, Intra–specific competition,
Apparent completion, Competitive exclusion, Resource–partitioning, Contest vs.
scramble competition, Inter-specific competition, Competitive exclusion
principle, Armstrong and McGehee model, Exploitative competition, mutualism,
Symbiotic mutualism, Non–symbiotic mutualism, Isoclines.
