A multitude of harlequin lifeforms bobbed and twirled and played in the depths of the Atlantic. Pink cucumbers with thorny backs. Algae. Starfish. Annelids with simple brains and a hundred toes. Sponges—like yellow, swollen hands—sucked in water and pushed out oxygen. Most amusing were the mysterious buggers who had no likeness on the previous earth; tiny beasts with exotic exoskeletons engraved with deep grid-like patterns, snails with horns, and slithering plants that looked like magenta weeping willows.

— Jake Vander-Ark

An attempt to study the evolution of living organisms without reference to cytology would be as futile as an account of stellar evolution which ignored spectroscopy.

— J.B.S. Haldane

And you are made of a hundred trillion cells. We are, each of us, a multitude.

— Carl Sagan

An evolutionary perspective of our place in the history of the earth reminds us that Homo sapiens sapiens has occupied the planet for the tiniest fraction of that planet's four and a half thousand million years of existence. In many ways we are a biological accident, the product of countless propitious circumstances. As we peer back through the fossil record, through layer upon layer of long-extinct species, many of which thrived far longer than the human species is ever likely to do, we are reminded of our mortality as a species. There is no law that declares the human animal to be different, as seen in this broad biological perspective, from any other animal. There is no law that declares the human species to be immortal.

— Richard E. Leakey

An example of such emergent phenomena is the origin of life from non-living chemical compounds in the oldest, lifeless oceans of the earth. Here, aided by the radiation energy received from the sun, countless chemical materials were synthesized and accumulated in such a way that they constituted, as it were, a primeval “soup.” In this primeval soup, by infinite variations of lifeless growth and decay of substances during some billions of years, the way of life was ultimately reached, with its metabolism characterized by selective assimilation and dissimilation as end stations of a sluiced and canalized flow of free chemical energy.

— R.W. van Bemmelen

Angelo," he said, and felt the bed rock as Angelo shuddered, caught halfway between REM Antonia - the inhibition of movement caused by the shutdown of monoamines in the brain - and waking.

— Elizabeth Bear

Animals have genes for altruism, and those genes have been selected in the evolution of many creatures because of the advantage they confer for the continuing survival of the species.

— Lewis Thomas

An irrefutable proof that such single-celled primeval animals really existed as the direct ancestors of Man, is furnished according to the fundamental law of Biogen by the fact that the human egg is nothing more than a simple cell.

— Ernst Haeckel

Another explanation for the failure of logic and observation alone to advance medicine is that unlike, say, physics, which uses a form of logic - mathematics - as its natural language, biology does not lend itself to logic. Leó Szilárd, a prominent physicist, made this point when he complained that after switching from physics to biology he never taken a peaceful bath again. As a physicist he would soak in the warmth of a bathtub and contemplate a problem, turn it in his mind, reason his way through it. But once he became a biologist, he constantly had to climb out of the bathtub to look up a fact.

— John M. Barry

A nutritive center, anatomically considered, is merely a cell, the nucleus of which is the permanent source of successive broods of young cells, which from time to time fill the cavity of their parent, and carrying with them the cell wall of the parent, pass off in certain directions, and under various forms, according to the texture or organ of which their parent forms a part.

— John Goodsir