Ecology Chapter 11

Competition

An interaction of individuals over a limiting resource that leads to a decreased fitness of at least one competing individual.

Interspecific Competition

Competition between different species

Intraspecific Competition

Competition among individuals of the same species.

Self-Thinning

At high densities, the population declines, but remaining individuals grow larger.

How to show if competition is involved.

The resource is limiting and the interaction between species has a negative impact on the both of them.

Exploitation Competition

One species reduces the amount of availability of the limiting resource.

Interference Competition

One species actively inhibits another from obtaining the resource.

Preemptive Competition

A mechanism that ensures access to the limiting resources (e.g early establishment in a resource-rich area)

Apparent Competition

Two species preyed upon by the same predator; the apparent competition is caused by that enemy’s numerical response.

Diffuse Competition

The combined effect of two or more competitors rather than a single competitor is significant.

Ecological Niche

The set of biological and physical resources that determine growth, survival and reproduction.

Disturbance

Leads to lower population size and lower competition, or reducing resources and increasing competition.

Fundamental Niche

A niche without any other opposing factors, niche at it’s true potential.

Realized Niche

A niche with added competitors and varied resources that effects the species in it.

Competitive Exclusion Principle

If niches overlap between two species, eventually one species will exclude the other. Degrees of overlap matters.

Character Displacement

Competition-driven divergence of the niches of two competing species.

Alpha

The competition coefficient effect of one species on another (e.g of 1 on 2 or 2 on 1)

Coexistence

A possibility if the niche overlap of the two species is small, and the carrying capacity is similar.