Intraspecific and Interspecific Competition & Social Structures (Video Notes)

25 vocabulary flashcards covering concepts from intraspecific and interspecific competition, territories, social hierarchies, group living, dispersal, metamorphosis, and basic insect/bird niche differentiation.

Intraspecific competition

Competition for scarce resources among individuals of the same species (e.g., mates, nesting sites, breeding territories, food, space).

Interspecific competition

Competition between two species for the same resource; can reduce plant growth in plants and reproductive rates in animals as density increases (natality/mortality effects).

Natality

Birth rate; can decline as resource competition increases and density rises.

Mortality

Death rate; can increase as density rises and competition intensifies.

Ritual fighting

Non-lethal wrestling or pushing matches used to test strength; costly in energy and may cause injury or death; not typically lethal duels.

Home range

The broad geographical area in which an animal searches for resources; not actively defended.

Territory

A defendable sub-area within the home range, used to secure nests, mate, and raise young; actively defended.

Territory marking

Signalling to keep others out, such as urine or scent marking of an area.

Threat displays

Displays or vocalizations at boundaries to deter rivals without fighting.

Territorial fighting

Fighting as a last resort to defend territory; costly and risky, so avoided when possible.

Social hierarchy

A ranking system within a group that determines access to resources and mates.

Pecking order

A linear dominance hierarchy commonly observed in chickens, showing relative ranks.

Alpha

The most dominant, top-ranked individual in a group.

Linear dominance hierarchy

A straightforward, linear ranking where each member has a rank relative to all others.

Complex dominance hierarchy

A non-linear system with subordinate groups, bonding pairs, families, and division of labour.

Establishing hierarchies

Competition for rank early on; initial aggression; after establishment, fighting decreases and rank is maintained by posture/display.

Dominant display

Signals of dominance such as standing tall, puffed feathers, tail erect, snarling, or exposed teeth.

Submissive displays

Appeasement signals to prevent attack, e.g., smaller size, lowered head, avoiding eye contact, cringing, tail tucked; rolling onto back as ultimate submission.

Advantages of group living

Safety in numbers, more mate options, potential specialization, cooperative food gathering, and improved locomotion.

Disadvantages of group living

Higher disease risk, greater predation risk for large groups, and increased competition leading to conflict.

Dispersal to reduce competition

Some species disperse offspring away from parents (e.g., free-swimming larvae) to settle far from adults and reduce competition.