Competition

Competition

a non-trophic interaction between individuals of two or more species in which all species are negatively affected by their shared use of a resource that limits their ability to grow, reproduce, or survive

Two types of competition

interspecific & intraspecific

Resources

components of environment that are required by a species

Exploitation competition

when species compete indirectly through their mutual effects on availability of a shared resource

interference competition

one species directly interferes with the ability of its competitors to use a limiting resource

Allelopathy

individuals of one species release toxins that harmanother species

Competition can vary in intensity depending on __________.

resource availability and type 

Competitive exclusion

dominant species drives the other to extinction

competitive coexistence

coexist despite sharing limiting resources

Competitive Exclusion Principle

two species that use a limiting resource in the same way cannot coexist indefinitely (if competition is very weak, though, competitive exclusion is less likely)

Resource partitioning (sometimes AKA niche partitioning)

species use limiting resources in different ways 

character displacement

when competition causes the phenotypes of competing species to evolve to become different over time

Population size of species 1 doesn’t change when ______. Population size of species 2 doesn’t change when _______. 

N₁ = K₁ - αN₂, N₂ = K₂ - βN₁ 

Abundance of species 1 doesn’t change when ________. Abundance of species 2 doesn’t change when _________.

N₂ = K₁/α and N₁ = K_1, N₁ = K₂/β and N₂ = K₂

Coexistence can only happen when:

α < K₁/K₂ < 1/β

The closer α and β are to one another, the closer _______ have to be for coexistence to happen

K₁ and K₂

Competitive reversal

when the species that is the inferior competitor in one habitat becomes the superior competitor in another

fugitive species

a species that must disperse from one place to another to take advantage of disturbances that open up resources and allow them to avoid competitive exclusion