The Theory of Island Biogeography
Think of a large office building. It can hold many different people, possibly even
several different companies. A smaller office building will hold far fewer people,
and may be limited to only one or two different companies. The limit is due to
the amount of space - a larger space can hold more people and more
companies, while a smaller space can't hold as many.
The same idea applies to
. The theory of island
biogeography simply says that a larger island will have a greater number of
species than a smaller island. For this theory, an 'island' is any ecosystem that
is remarkably different from the surrounding area. So, this could refer to an
actual island in the ocean, or it may be an oasis that is surrounded by a
The theory predicts other things, too. For instance, everything else being equal,
distant islands will have lower immigration rates than those close to a
mainland, and equilibrium will occur with fewer species on distant islands.