How do ecologists use history to understand the distribution of organisms?
History plays a vital role in determining the distribution of organisms across the globe. As populations adapt and evolve over time, the new species that appear are localized in very specific areas. They are endemic, or native, to that area only. These new populations, however, may travel and find new areas to habitat through a process called biotic interchange. The history of this process for each species is important to their modern distributions.
The historical climate and location of the original habitat are key aspects to this process. The conditions of the environment in which they evolved most likely represents the types of climates that you would find them in today. Additionally, species are only found within travel distance of their original habitat. The areas that most species are confined to are called biogeographic regions and are often defined by natural barriers such as mountain ranges or deep ocean channels. These obstacles are difficult for organisms to migrate through, and therefore limit population travel. Today, examples of these are the Himalayan Mountains and the Wallace in Indonesia.
It is important to keep continental drift and historic geography in consideration as well. The barriers that define regions today are not the same as the ones that were in place in the past.