Here's a pretty cool example of how isolated environments lead to
the evolution of new species. The more isolated, the more unique:
Israeli scientists said on Wednesday they had discovered a prehistoric ecosystem dating back millions of years.
The discovery was made in a cave near the central Israeli city of
Ramle during rock drilling at a quarry. Scientists were called in and
soon found eight previously unknown species of crustaceans and
invertebrates similar to scorpions.
"Until now eight species of animals were found in the cave, all of
them unknown to science," said Dr Hanan Dimantman, a biologist at the
Hebrew University of Jerusalem. [...]
The cave was completely sealed off from the world, including from
water and nutrients seeping through rock crevices above. Scientists who
discovered the cave believe it has been intact for millions of years.
"Every species we examined had no eyes which means they lost their sight due to evolution," said Dimantman.
The cave is an "island" of sorts, and like islands out in the ocean,
it has unique species that can be found nowhere else. Isolated
populations that have their gene pools cut-off from their parent
populations tend to speciate rather quickly.