Race is a taxonomic classification below species. It is also less formalized than species. Contrary to the other answers, race is definitely used in biology, especially historically and in certain fields. read more
• Race is a system of classification of human beings only, whereas species is the most refined division of all life forms. • Race has no biological basis whereas organisms that can mate and produce offspring are classified under the same species category. read more
Races may be genetically distinct populations of individuals within the same species, or they may be defined in other ways, e.g. geographically, or physiologically. Genetic isolation between races is not complete, but genetic differences may have accumulated that are not (yet) sufficient to separate species. read more