Intraspecific Relationships

intraspecific competition

competition between members of the same species. Intense because they all share the same niche and compete for the exact same resources.

Cooperative groups

species where individuals perform behaviours that help one another.

Agonistic behaviors

Any behavior related to fighting within a species. Most agonistic behaviors are ritualized contests that determine which competitor gains access to a resource, such as food or mates. Overall this behavior reduces conflict in the population.

Examples of agonistic behavior

- tests of strength
- competitive displays/dances
- vocalisations/calls

Hierarchy

Social order of individuals in a group according to their status/rank in the group. Rank is determined by ritualised activities eg. grooming, threats, displays, vocalisations.

Dominance

High ranking individuals in a group. Often the strongest/most fit, and have best access to resources including mates.

Costs of dominance

- higher metabolic rate so need more food
- have to use energy defending territories
- high levels of stress hormones
- have to engage in more ritualised fights to defend rank

Benefits of dominance

- first access to food
- spend less time hunting/foraging
- best access to mates/more mates
- fittest individuals do the most survival/mating so best genes spread through the population

Subordinance/submissive

Individuals who display behaviors that show they are at the bottom of a social ranking eg. rolling over, displaying neck, averting eye contact.

Complex hierarchy

A kind of hierarchy where groups of individuals hold the top rank. Eg. In wolf packs, relatives of the alpha male and female hold a higher rank than other wolves which may actually be stronger than them.

Linear hierarchy

A hierarchy where each individual dominates all individuals below, but not those above. From alpha at the top to the omega individual at the bottom.

Alpha individual

Dominant individual in a linear hierarchy

Omega individual

Most submissive individual in a linear hierarchy

Home range

An area that an animal uses for food/foraging, but will not actively defend.

Territory

An area that an animal actively defends. Usually where it keeps mates, offspring, or other precious resources that need to be defended. The closer an intruder gets to the center of a territory the more escalated the defensive behavior becomes.

Territorial behavior

Competitive behavior in which an animal tries to adopt and defend a physical area against others of the same species.

K-strategist

reproductive strategy in which organisms create only a low number of offspring but invest lots of time and resources in caring for them.
Adaptive advantage: useful strategy when environment is stable and there is strong competition

r-strategist

reproductive strategy in which organisms create a high number of offspring and invest little time or resources in caring for them.
Adaptive advantage: useful strategy when environment is changing and competition is weak.

Monogamy

One male mates with one female for a breeding season. Advantage: share energy investment in caring for young, and protecting territory.

Pair bond

One female mates with one male for their whole lives. Lots of time and energy is invested in courtship and reinforcing the pair bond. Advantage: share energy investment in caring for young, and protecting territory.

Polygyny

One male mates with several females. Fast reproduction rate since one male can impregnate many females. Advantage: strongest alpha males do most of the mating so the best genes for survival get passed among the population.

Polyandry

One female mates with multiple males. Advantage: female can select who to mate with and will often pick a mix of the fittest males. Some females can select which sperm to allow to impregnate her eggs.

Polygynandry

Multiple males mating with multiple females multiple times. Advantage: increases genetic diversity of the population. But fittest individuals mate at same rate as all other individuals so fitness of the population may not increase.

Courtship behavior

behaviors that allows males and females of the same species to recognize each other and prepare to mate. Behaviors indicate individuals are sexually mature and are used to compete for mates.
Advantage: individuals don't waste time trying to mate with the wrong species or sexually immature individuals.

Sexual dimorphism

Differences in physical characteristics between males and females of the same species. Evolves due to intraspecific competition for mates eg. males evolve larger and larger horns to impress females in ritualized fights. Advantage: makes mate selection for the fittest mate easy.

Parental care

Any action by which an animal expends energy or assumes risks to benefit its offspring (e.g., nest-building, feeding of young, defense). Increases chance that offspring will survive but is costly to the parents.