Animal Ecology Test 2

Population growth which is limited by the environment and exhibits a sigmoidal or S-Shaped growth curve.

r = intrinsic rate of increase
N= current population size

r decreases, as N increases

Maximum number of individuals that can be supported in a given environment.

Region of curve when population is small and growth is slow.

Region of curve where growth accelerates and begins to resemble exponential growth.

region of graph where growth begins to slow as it approaches the carrying capacity.

N/K= environmental resistance

Abiotic factors which act upon population size such as floods, geologica events, snowfall precipitation, temperature (independent of population size)

Less predictable in their effects

Biotic factors which act upon population size such as:
Density dependent mortality
Density dependent fecundity
Disease and Competition

May function to limit population size through a variety of mechanisms.

May limit breeding to a few select members (Dominance)

May limit the number of individuals within a given areas

May encourage individuals to emigrate into new areas in search of new territory or mates

HIghly complex level of social behavior (prides, packs, colonies etc)

Individuals of more than one generation live together

Cooperative care of the young

Division of individuals into reproductive and non-reproductive castes.

The total fitness of an individual and the fitness of its relatives.

Differential reproduction among closely related individuals based on genetic variation in social behavior.

Alternatively, the evolutionary force which favors altruism.

A form of behavior in which an individual increases the welfare of another at the expense of its own welfare (self-sacrificing behavior)

Provides a means of reducing intraspecific competition

Dispersal can be permanent (individuals do not return)

Dispersal can also be annual or seasonal (migration)

Annual migrations reduce competition for food and mates in many species (especially during breeding seasons)

Annual migrations of large ungulates such as elk and caribou

Annual migrations of many avian species such as geese, swallows, and cranes

Annual migration of many aquatic species such as the grey whale and the humpback whale

The area which an organism utilizes

Larger organisms require larger home ranges

Carnivores require larger ranges than herbivores

That part of the home range which is actively defended by an organism