Spea bombifrons, Spadefoot toad
How do scientists know if an organism is one species or another, and how do they know whether a critter is a subspecies? In short, what defines a species? I started asking scientists at the Florida Museum of Natural History about this when I worked there as a staff science writer. Many researchers would come back from survey trips with what they said were species new to science, or paleontologists would come back from digs with bits of fossil bone that they said also represented new species. In the beginning, I passively accepted their assertions, making careful notes of what features distinguished this newly discovered organism from its close relatives. Then I began to wonder about the boundaries that separate species. (more…)
