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.
demographic-based population model
modern model of population dynamics incorporating many features of the r– and K-selection theory
regulation of population that is influenced by population density, such as crowding effects; usually involves biotic factors
regulation of populations by factors that operate independent of population density, such as forest fires and volcanic eruptions; usually involves abiotic factors
competition between species for resources in a shared habitat or environment
species suited to stable environments that produce a few, relatively large offspring and provide parental care
species suited to changing environments that produce many offspring and provide little or no parental care