KEY CONCEPT Every organism has a habitat and a niche.

A habitat differs from a niche. A habitat is all of the abiotic and biotic factors in an area in which an organism lives. Habitat includes fields of dense grass. Open and partly open country in a wide variety of situations, often around human habitation. Nests in buildings, caves, crevices on cliffs, burrows, and hollow trees, rarely in trees with dense foliage. Eastern Bluebird Sialia sialis Barn Owl Tyto alba Habitat includes forest edge, open woodland, and partly open situations with scattered trees, to riparian woodland, also pine woodland .Nests are in natural cavities, old woodpecker holes, or similar sites, mostly 3-20 feet (1-6 meters) above ground.

An ecological niche includes all of the factors that a species needs to survive, stay healthy, and reproduce. food abiotic conditions behavior An insectivorous or omnivorous birds; often flies from low perch to ground to feed on beetles, are territorial, prefer open grassland with scattered trees and are cavity nesters Eats mainly small mammals, especially voles, birds can be taken when small mammals are scarce. Dense grass fields are the chief foraging habitat, pastures, grass hayfields, and recently abandoned agricultural fields

Resource availability gives structure to a community. Species can share habitats and resources. Competition occurs when two species use resources in the same way. Competitive exclusion keeps two species from occupying the same niche. One species that is best suited to the niche will survive and the other will die out (extinct) or be pushed into another niche.

Competitive exclusion has different outcomes. One species is better suited to the niche and the other will either be pushed out or become extinct. The niche will be divided. The two species will further diverge.

Niche Partitioning Niche is divided so that all the species can survive.

Evolutionary response Organisms evolve to fit a niche.

Ecological equivalents are species that occupy similar niches but live in different geographical regions. Madagascar South America