Populations

Population All the individuals of one species that occupy a certain geographical area during a certain time.

Natality the number of offspring born in one year.

Mortality the number of individuals that die in one year.

Immigration movement into an area.

Emigration movement out of an area.

Carrying Capacity Is the maximum number of organisms the resources of an ecosystem can support.

Four factors help to determine the carrying capacity of a population Materials and Energy Food Chains Competition Density

Materials and Energy limits on the useable energy from the Sun, supply of water, carbon and other essential materials.

Food Chains their food supply and their predators limit populations.

Competition all organisms need the same thing from their environment as the rest of the members of its species do. This demand for resources results in competition. Interspecific Intraspecific

Interspecific Competition competition between species. Intraspecific Competition competition among members of the same species.

Density the population density of an organism depends on their requirement for space. Density-dependent factors: factors that increase in significance as a population grows. Example: food shortage. Density-independent factors: factors that affect a population regardless of its size. Example: flood or fire.