Under the biological species concept, a species is a group of organisms that
T he term species is defined as a group of organisms which interbreeds under natural circumstances, producing viable, fertile offspring, and which is reproductively isolated from other groups.This definition is known as the Biological Species Concept.hapter 4: Speciation and Phylogeny What is a species? The term species is defined as a group of organisms which interbreeds under natural circumstances, producing viable, fertile offspring, and which is reproductively isolated from other groups.
A species is often defined as the largest group of organisms where two hybrids are capable of reproducing fertile offspring, typically using sexual reproduction. While in many cases this definition is adequate, the difficulty of defining species is known as the species problem.his definition can be extended to say that a species is a group of organisms that could potentially interbreedâfish could still be classed as the same species even if they live in different lakes, as long as they could still interbreed were they ever to come into contact with each other.