Ray was also the first person to produce a biological definition of species.

To reflect the minimum phenomena required, other biological definitions of life have been proposed, many of these are based upon chemical systems.

'Then he's still alive, at least by some biological definition?'

Perhaps the same biological definition,' said Wedderkind, 'but we also define life as being the period between birth and death.

He was the first person to give a biological definition of the term species.

John Ray (1686), an English naturalist, was the first to give a biological definition of the term species.

That, however, is a biological definition, a sophisticated one.

The modern biological definition of race developed in the 19th century with scientific racist theories.

Some biological definitions of child include the fetus, as being an unborn child.

He was a man possessed by his past, a human being only in the biological definition of the word.