Population Ecology

Vocabulary flashcards covering core concepts of population ecology, population dynamics equations, growth models, regulatory mechanisms, and spatial dispersion patterns.

Population

A group of individuals of the same species that occupy the same general area, rely on the same resources, are influenced by the same environmental factors, and have a high likelihood of interacting and breeding with one another.

Population ecology

The subfield of ecology that examines how and why populations of a given species change in size and density over time.

Population density

The number of individuals of a species per unit area of habitat.

Population size ($N$)

The total number of individuals that make up a population.

Per capita birth rate ($b$)

The absolute number of births ($B$) divided by the total population size ($N$), calculated as $b = \frac{B}{N}$.

Per capita death rate ($d$)

The absolute number of deaths ($D$) divided by the total population size ($N$), calculated as $d = \frac{D}{N}$.

Per capita growth rate ($r$)

The per capita birth rate ($b$) minus the per capita death rate ($d$), represented by the equation $r = b - d$.

Maximal intrinsic rate of increase ($r_{\text{max}}$)

The maximum rate at which a population can grow, achieved only under ideal conditions with unlimited resources, ideal abiotic conditions, and no predators, parasites, or disease.

Carrying capacity ($K$)

The maximum population size ($N$) that a given environment can support indefinitely.

Exponential growth model

A growth model characterized by a J-shaped curve, describing population growth in unlimited resource conditions where the population grows by $rN$.

Logistic growth model

A population growth model represented by $rN \times \frac{K - N}{K}$, in which per capita growth rate slows as population size ($N$) approaches carrying capacity ($K$).

Intraspecific competition

Competition for limited resources between individuals of the same species, which intensifies at higher population densities.

Density-dependent regulation

Population regulation mechanisms, such as intraspecific competition or predator-prey dynamics, whose impact on survival and reproduction varies depending on population density.

Density-independent factors

Abiotic environmental events and disturbances (e.g., fires, floods, droughts) that limit population size regardless of population density.

Dispersion patterns

The spatial arrangement of individuals within a population across their habitat, categorized into uniform, random, or clumped distributions.

Uniform dispersion

A dispersion pattern in which individuals are evenly spaced throughout a habitat, usually resulting from direct competition for scarce resources or territorial interactions.

Random dispersion

A dispersion pattern where an individual's position is independent of others, occurring when resources are uniformly distributed and individuals lack strong attractive or repulsive interactions.

Clumped dispersion

The most common dispersion pattern, where individuals aggregate in patches due to localized resource distribution, social behaviors, or cooperative defense and hunting.