Most biologists have assumed that a mother and her fetus have an underlying "harmony of interests," because the fetus carries its mother's genes.

So impressively precise is the orchestration of these courting males that biologists have long assumed that they must be cooperating to keep their signals closely matched.

Most biologists working within the modern synthesis assumed that an organism is a straightforward reflection of its component genes.

Until recently biologists assumed that monotremes, alone of all mammals, do not experience the type of sleep known as rapid-eye-movement, or REM, sleep.

Nearly all birds form pairs during the breeding season, and biologists assumed that the pair bond was necessary for the survival of the young.

Consequently, biologists assumed it had evolved its lens independently and in an entirely different fashion.

Researchers now say that in contrast to what biologists had assumed, parasitism may be a sign of good health.

But though biologists assume that nature loves parsimony, this remains to be proved.

Aging involves hundreds of different things going wrong all over the body, a multitude of ills that biologists have long assumed could never be addressed by a single treatment.

But evolutionary biologists do not assume that every trait is a sign of perfect design, or that natural selection works toward the ultimate happiness and well-being of an individual creature.