Final answer:
A species is a group of individual organisms that interbreed and produce fertile, viable offspring. The biological definition of species emphasizes reproductive compatibility as the main criterion for determining species. Species definitions can be controversial and rely on a combination of behavior, genetics, and morphology.
Step-by-step explanation:
A species is a group of individual organisms that interbreed and produce fertile, viable offspring. This means that members of the same species share enough genetic similarities to reproduce and have offspring that can also reproduce. For example, all human beings alive today belong to the species Homo sapiens. Humans can interbreed with each other but not with members of any other species.
There are different definitions of species, but the biological definition is commonly used. It states that a species is a group of actually or potentially interbreeding organisms. This definition focuses on reproductive compatibility as the main criterion for determining species.
It is important to note that species definitions are not always clear-cut and can be controversial. Different organisms may look different but still belong to the same species, while others may look similar but belong to different species. In practice, scientists often rely on a combination of behavior, genetics, and morphology to determine species.