The natural world is infinitely complex and hierarchically structured, with smaller units forming the components of progressively larger systems: molecules make up cells, cells comprise tissues and organs that are, in turn, parts of individual organi...

For biologists, 2009 was an epochal year: the bicentennial of Charles Darwin's birth and the 150th anniversary of the publication of a book now known simply as "The Origin of Species". But for many botanists, Darwin's true legacy starts with the 1862...

The history of biology is populated by numerous model species or organisms. But few vertebrate groups have aided evolutionary and ecological research more than the live-bearing fishes of the family Poeciliidae. Found throughout tropical and subtropic...