Habitat is the distribution and quality of resources that contribute to fitness. It is the resources and condition present in an area that produce occupancy by an organism including: Availability is the accessibility of physical and biological components. Use is the way an animal uses a collection of abiotic and biotic resources for survival. Suitability habitat that can support an organism (hsi: habitat suitability index) Plant communities, vegetative associations, cover types, etc Clements: species" (resources) distribution peaks are concentrated in discrete groups. Gleason: species" (resources) distributional peaks are scattered along the gradient. Habitat selection: hierarchical process involving a series of innate and learned behavioral decisions made by an animal at different geographic scales to determine a location to acquire resources in a habitat. Habitat preference: the process of habitat selection that results in disproportional use of some biotic resources over others. 1st order = range; the geographical range of a species.