Characteristics Of Populations PDF

Characteristics of Populations To better understand interaction between organisms in nature, ecologists need to define a number of terms Species ∗ group of organisms which have ability to interbreed, under natural conditions, to produce fertile offspring Population size ∗ number of individuals o...

Characteristics of Populations To better understand interaction between organisms in nature, ecologists need to define a number of terms Species ∗ group of organisms which have ability to interbreed, under natural conditions, to produce fertile offspring Population size ∗ number of individuals of species occupying given area at given time Population density ∗ number of individuals of species per unit area or volume Crude density ∗ number of individuals per total area Ecological density ∗ number of individuals per unit area that is actually used Deer mice (Peromyscus maniculatus) in Population size = 400 Ninigret pond watershed Total area = 12 km2 Area used = 9 km2 Crude density = 400 ÷12 km2 = 33.3 mice/km2 Ecological density = 400÷ 9 km2 = 44.4 mice/km2 Habitat ∗ place where species normally lives Niche ∗ role or function of species within an ecological community Community ∗ all populations in a given ecosystem at a given time Ecosystem ∗ living (biotic) and non-living (abiotic) components that function as a unit in a given area or volume  POPULATION DISPERSION Since resources are not always distributed through environment in same way, all populations do not show same pattern of dispersion Clumped ∗ most populations show this pattern Random ∗ when resources are evenly distributed and there is little interaction between individuals Uniform ∗ individuals are equal spaced apart (almost never seen in nature, but this is the way that crops are planted)