Lecture week 13 (11-14) - Notes Competition and Niche Space.docx

Competition

Individuals interacting where both sustain some cost (or potential cost), a - / - interaction.

Within and between species, allows for those with certain traits to be better competitors.

Those species that out-compete others have greater fitness, thus creating populations of better competitors.

(+/-) is the ultimate payoff (the reason for the competition)

Intraspecific Competition

Competition between individuals within a species.

major cause of density-dependent growth of a population.

Interspecific Competition

Competition between individuals of different species for the same resources.

Niche

Summarizes the environmental factors that influence the growth, survival, and reproduction of a species.

Fundamental Niche

The physical conditions under which a species might live, in the absence of interactions with other species (the abiotic environment)

Realized Niche

The actual niche of a species that is restricted through its interactions with other species.

Competitive Exclusion Principle

Two species with identical niches cannot coexist in that niche indefinitely.

Resource Partitioning

The differentiation of niches, both in space and time, that enables similar species to coexist in a community.

Resource Segregation

One difference between species resulting from past competition.

Scramble Competition

Competing individuals target the resource, and there may be no direct interaction between the two.

Interference Competition

Individuals target the competitor, and not necessarily the resource.

How do community ecologists define various interactions?

By considering those who benefit from the interaction (+), versus those that sustain a cost (-) and those that do not see a benefit or a cost (0).

Which competition suffers most cost?

Intraspecific competition could have potentially higher costs due to the complete overlap in requirements between individuals.

The Generel Adaptation Syndrome

A physiological-based response system where short-term gains of survival in high population density situations are paired with long-term costs.

What is one possible outcome of infraspecific competition?

Superior competitors will have a greater fitness than lesser competitors will.

n-dimensional hypervolume

where n = the number of environmental factors important to the survival and reproductions of the species.

Where can interspecific competition lead to?

An Evolutionary Arms Race, where adaptation of one species are overcome by the selection for traits within another species, which is countered by the evolution of new traits in the first to overcome adaptations by the second.