2 of 7

Intraspecific competition

Competition occurs when individuals use the same resources that are in limited supply.

Intraspecific competition is stronger than interspecific competition

This is because individuals within a species are competing for the same resources... e.g. food, mates, nesting sites.

3 of 7

Competition limits population size

Intraspecific competition increases with density,

i.e. as population no. increases, competition for resources increase. This is because there are more individuals competing for the limited resources.

As a population reaches carrying capacity (K), there is decreased natality (birth rate) and increased mortality rate to regulation population size.

Negative effects of Competition

Aggression and agonistic behavior

Competition (e.g. for mates or territory) may lead to aggressive encounters between individuals.

Agonistic behaviour results in a reduction of aggression.

Loss of strong healthy individuals would not benefit the group.

'Trials of strength' are an agonistic behaviour where the weaker animal gives in/submits.

E.g. Elephants though they gore predators with their tusks, when fighting other elephants, have a 'pushing competition'

Aggression and agonistic behavior 2

Agonistic behaviour involves postures, gestures and vocalisations that are understood as either threatening or submissive.

Describe the behaviour of the two dogs pictured.

Which is submissive, which is threatening?

Aggression and agonistic behavior 3

List the following postures as either dominant or submissive agonistic behaviours: