11: Intraspecific Population Regulation

Density-independent regulation

-characteristics

-what causes this?

-what kind of environments?

1) happens regardless of population density

2) population rarely reaches K

3) unstable & unpredictable environments

-caused by catastrophes(fires, hurricanes, seasons) & occurs periodically

-J-shaped curves

Density-Dependent Regulation

-characteristics

-what is it caused by?

-what kind of environment

1) occurs as population density increases

2) population stabilizes at K

3) stable, predictable environments

-caused by predation, competition, diseases

-logistic curve growth(S shape)

At what point is population growth the greatest?

intermediate population levels

At what size does a population decline?

when it exceeds K or falls below minimum population size

What causes intraspecific competition to occur?

-what are the 2 types?

limited resources & high population density

1) contest competition

2) scramble competition

contest competition

-what is it regulated by?

-what happens to the population?

example?

individuals directly compete w/ each other by confrontation for access to resources

-regulated by territoriality or social dominance

-maintains stable population density

ex// elk protecting his females from other elk

scramble competition

example?

individuals scramble to get resources ASAP w/o confrontation(equal sharing)

-individuals get less than they need to survive

-produce chaotic fluctuations in populations bc EVERYONE is cooked

ex//catipillars strip tree of bark but NO ONE reaches adult size

ex// salmon rushing for food in water

What are the mechanisms of intraspecific competition?

1) stress →lead to bad immunity & mortality

2) dispersal (emigration)
3) social dominance

4) territoriality

Total Range

entire area covered by an individual animal in its lifetime

Home range

area that an animal learns throughly & habitually controls

ex// PUC

territory

area occupied more or less exclusively by an animal or group of animals by means of repulsion thru defense or advertisement

ex// your room

core area

area of heaviest regular use within the territory, often centered on sleeping

ex// bed or desk for studying

individual distance

minimum distance that an animal routinely keeps between itself & other members of the same species when not on the territory

ex// personal space

Many species are ______ during breeding season & ______ during non-breeding season.

territorial ; non-territorial

what is philopatry? Which animal is this common in?

return of territorial individuals to same territory every year

-common in migratory birds on both breeding & wintering territory

benefit of increased fitness?

access to resources, including reproduction

Examples of defending territory

advertisements, warnings, or fighting

ex// songs of birds

ex// scent marks of animals

what are floaters or satellite individuals? characteristics?

“homeless” individuals that lack territory & wander between territories

-tolerated by residents when resources are abundant

-use devious mating strategies

When animals fight for a territory, does one usually die?

No, fighting is frequent but death is rare

In territorial disputes between owner & rival, who usually wins?

territory owner, who is usually more fit (stronger & bigger)

Are territorial disputes usually between neighbors or between an owner and a stranger?

Between an owner & a stranger, bc neighbors recognize each other & rarely challenge each other

how useful is it to relocate individual animals in trouble?

useful only if there is vacant territory w/ adequate resources

What is space capture?

area that plants occupy to get water, nutrients and sunlight

What is allelopathy?

chemical compounds released into soil to inhibit germination & growth of competing plants

-occurs in some bacteria, fungi, algae, plants, or coral