In the last episode, Chris and Mike briefly touched on how biology and the similarity of organisms can tell us how recently organisms in different areas had been separated.  This is a field called Biogeography.  And this is the topic for today.  We consider how the Earth's latitude affects life and how islands are interesting examples of isolated organisms evolving on their own.

If you have an idea for a future episode, please email us at crisscrossingsci@gmail.com and we will try to answer your questions.