U6A: Population and Ecosystem Changes Vocabulary

Population Density

Number of individuals per unit area.

Population Distribution

How individuals are spaced out across their range.

Age Structure

The number of males and females of each age group in a population.

Immigration

Movement of individuals into an area occupied by an existing population.

Emigration

Movement of individuals out of an area.

Exponential Growth

Growth pattern in which individuals in a population reproduce at an increasing rate.

Logistic Growth

Growth pattern in which a population’s growth slows and then stops following a period of exponential growth.

Carrying Capacity

Largest number of individuals of a particular species that a particular environment can support.

Limiting Factor

Factor that causes population growth to decrease.

Density-Dependent Limiting Factor

A limiting factor that depends on population density.

Density-Independent Limiting Factor

Limiting factor that affects all populations in similar ways, regardless of population density.

Ecological Succession

Series of gradual changes that occur in a community following a disturbance.

Primary Succession

Succession that occurs in an area in which no trace of a previous community is present.

Pioneer Species

First species to populate an area during succession.

Secondary Succession

Succession that occurs in an area that was only partially destroyed by disturbances.

Biodiversity

Total of the variety of organisms in the biosphere.

Ecosystem Diversity

Variety of habitats, communities, and ecological processes in the biosphere.

Species Diversity

Number of different species that make up a particular area.

Genetic Diversity

Sum total of all the different forms of genetic information carried by a particular species, or all organisms on Earth.

Resilience

A natural or human system’s ability to recover after a disturbance.

Ecosystem Services

The benefits provided by ecosystems to humans.