The study of the past and current distribution of a given animal or plant species.
Examples:
- Tigers are not found in Africa at all, they are native to Asia only.
- While the Polar Bear could probably survive in Antarctica, it's only found in the Arctic. Penguins are never found in the Arctic region.
- Douglas-Fir: "Its growth range includes southwestern Canada and the northwestern United States, but extends down
through the Rocky Mountains as far as Mexico. It grows at altitudes from sea level to well over 10,000 feet."
The distribution can be at different scales - global, by region, or by landmass.
This would include evolutionary pressure on individual species and the Biological Species Concept. These pressures can be as a result of natural selection or as a result of new competition from Invasive species such as weeds. It also includes population control and effective population size. What is an optimal population density for a given area. See: speciation