2 Population Ecology Free Online FlashCards

What is a population?

A group of individuals of the same species living in the same area at the same time.

What does population size measure?

The number of individuals in a population.

What is population density?

The number of individuals per unit area or volume; it helps compare populations in differently sized areas.

What is clumped dispersion?

Individuals gather in patches, often near resources such as food, water, or shelter, or in social groups.

What is uniform dispersion?

Individuals are spaced relatively evenly, sometimes because they compete or defend territories.

What is random dispersion?

Individuals are spaced unpredictably, with little attraction or avoidance among them.

How is change in population size calculated?

$\text{Change in population size}=\text{births}+\text{immigration}-\text{deaths}-\text{emigration}$.

What characterizes exponential population growth?

In idealized exponential growth, plentiful resources and rapid reproduction let growth accelerate as the population gets larger, producing a J-shaped curve.

What is carrying capacity?

The population size an environment can sustain over time under particular conditions.

What does the logistic growth model describe?

The model is $\frac{dN}{dt}=rN\left(1-\frac{N}{K}\right)$. Growth slows as population size $N$ approaches carrying capacity $K$; $r$ is the intrinsic growth rate.

What is a limiting factor?

A resource or environmental condition that restricts a population's growth, size, or distribution.

What are density-dependent factors?

Factors whose effects become stronger as population density rises, such as competition, disease, and predation.