BSC 2011 Lecture 36: Ecology Lecture 6
Document Summary
Interactions between species may be positive, negative, or neutral. Interspeci c interactions affect population dynamics and species distributions. Interactions affect individual tness and can result in evolution. Interactions in uence population densities, alter species distributions, and lead to evolutionary change. Competition (-/-: both exert energy, use or de nes of a resource by an individual that decreases the resource availability to others. Density-dependent population growth re ects intraspeci c interactions among individuals in a population. Interspeci c competition-effect of other species subtracted in the growth model. Consumer-resource (+/-: predation, herbivory, parasitism, disease. Commensalism (+/0: cattle walking eld-helps birds nd bugs etc. Natural systems: coexistence of species more common: each species occupying a niche, resources are partitioned so that there is little direct competition for the same resource. Interspeci c interactions can affect the distribution of species. Competitive interactions can restrict the habitats in which species occur.