Population EcologyPopulations of species are described by density, spatial distribution, and growth rate.

Population Density is the number of

organisms per unit areaPopulation density of

cattle egrets is greater near the buffalo than farther away.

Spatial distributionDispersion is the pattern

of spacing of a population within an area

1 black bear/several hundred square kilometers

4 bison/km210 deer/km2

Population Growth Rate Emigration is the term ecologist

use to describe the number of individuals moving away from a population

Immigration is the term used to describe the number of individuals moving into a population

Carrying CapacityThe maximum number of

individual in a species that an environment can support for the long term

BiodiversityBiodiversity is the

variety of life in an area that is determined by the number of different species in that area

Genetic Diversity variety of genes or inheritable characteristics that are present in a population

Species diversity different species and the relative abundance of each species in a biological community

Ecosystem diversity variety of ecosystem that are all present in the biosphere

Threats to BiodiversityMass extinction is when a

large percentage of all living species become extinct in a relatively short period of time Dinosaurs

Natural resources are being destroyed or causing pollution.Fossil fuelsOld growth forestsNuclear FuelsHabitat loss

Overexploritation process of increase the current rate of extinction by excessive use, or species that have economic valueOcelotWhite rhinocerosBlack coral

Biological magnification is the increasing concentration of toxic substances in organisms as trophic levels increase in a food chain

DDT pesticide used in the 1940s, responsible for the near extinction of the American Bald Eagle

Eutrophication occurs when fertilizers animal waste, sewage or other substance rich in nitrogen and phosphorus flow into waterways.

Extensive algae growthFish Kills