Many people could differentiate a sparrow from a pigeon, hawk or duck. But to a biologist, the term "sparrow" wouldn't be descriptive enough — a biologist would want to know what species of sparrow they were looking at. But what, exactly, is a species, and how is it defined?
In biology, a species is the fundamental unit of taxonomy, the scientific system of categorizing life on Earth. And without the concept of a species, plenty of scientific endeavors, from wildlife conservation to public health, would be much more difficult.
