Classification of Living Organisms – Species
You have by now already come across the word 'species'. The word has a definite meaning in biology. Although the living world is vast and variable, scientists recognise well-defined forms or kinds of animals and plants. These kinds are the species (singular also 1s species). Ernst Mayr (1969) in his Principles of Systematic Zoology, has given a good definition for species. According to him. "Species is a group of actually or potentially interbreeding natural populations that are reproductively isolated from other such groups".
However, in a great many cases this stringent definition or criteria cannot be applied, and so in practice the identification and description of species is largely based on morphological and anatomical features. Normally the species is the lowest category of grouping used in taxonomy.