140 likes | 307 Views
Population Ecology. Populations of species are described by density, spatial distribution, and growth rate . Population Density. is the number of organisms per unit area Population density of cattle egrets is greater near the buffalo than farther away. . Spatial distribution.
E N D
Population Ecology • Populations of species are described by density, spatial distribution, and growth rate.
Population Density • is the number of organisms per unit area • Population density of cattle egrets is greater near the buffalo than farther away.
Spatial distribution • Dispersion is the pattern of spacing of a population within an area • 1 black bear/several hundred square kilometers • 4 bison/km2 • 10 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 Capacity • The maximum number of individual in a species that an environment can support for the long term
Biodiversity • Biodiversity 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 Biodiversity • Mass 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 fuels • Old growth forests • Nuclear Fuels • Habitat loss
Overexploritation process of increase the current rate of extinction by excessive use, or species that have economic value • Ocelot • White rhinoceros • Black coral
Biological magnification is the increasing concentration of toxic substances in organisms as trophic levels increase in a food chain • DDTpesticide 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 growth • Fish Kills