11.12 Population Interaction

Organisms belonging to different populations interact for food, shelter, mating or for other necessities. Interaction may be intra specific (interaction within the members of same species) or inter specific (among organisms of different species). Intra specific association is observed for all livelihood processes like feeding, territoriality, breeding and protection. Interspecific associations or interactions can be: Neutral: where different species live together but do not affect each other.

Positive: it is a symbiotic relationship in which no organism in association is harmed and either one or both may be benefitted. It is of two types – Mutualism and Commensalism. Negative: One or both of the interacting organisms will be affected as in case of competition, predation, parasitism. The common types of interspecific inter actions are: AMENSALISM (--, ): This is the ecological interaction in which an individiual species harm another without obtaining benefit, large powerful animals harm weak animals.

e.g., animals destroyed at the feet of elephants equilibrium is reached and maintained. Their growth is represented by S shaped growth curve. Biotic potential or Reproductive capacity (r) It is the maximum reproductive capacity of an organism under optimum environmental conditions.