Biogeography: This is the distribution of organisms in various parts of the earth. Over periods of ecological changes, biogeography contains the study of plant or animal species in their past or present living habitat or their survival locales. Modern biogeography offer employs the use of Geographic Information Systems (GIS), to understand the factors affecting organism distribution. Often mathematical models & GIS are employed to solve ecological problems which have a spatial aspect to them.
Biogeography is most deeply observed on the world's islands. These habitats are often much more manageable areas of study because these areas are more condensed than larger ecosystems on the mainland.