Summarizing Population Dynamics and Regulation

Summary

Populations are regulated by a variety of density-dependent and density-independent factors. Species are divided into two categories based on a variety of features of their life history patterns: r-selected species, which have large numbers of offspring, and K-selected species, which have few offspring. The r- and K-selection theory has fallen out of use; however, many of its key features are still used in newer, demographically-based models of population dynamics.

Glossary

demographic-based population model

modern model of population dynamics incorporating many features of the r- and K-selection theory

density-dependent regulation

regulation of population that is influenced by population density, such as crowding effects; usually involves biotic factors

density-independent regulation

regulation of populations by factors that operate independent of population density, such as forest fires and volcanic eruptions; usually involves abiotic factors

interspecific competition

competition between species for resources in a shared habitat or environment

K-selected species

species suited to stable environments that produce a few, relatively large offspring and provide parental care

r-selected species

species suited to changing environments that produce many offspring and provide little or no parental care