Before the gene was understood, before the double helix unwound, there was the grid — and the steady hand of D'Arcy Wentworth Thompson. In 1912, seated at his desk in Dundee, the Scottish zoologist began to draw. With India ink and a ruling pen, he traced a cod skull onto transparent paper, then deformed the Cartesian grid beneath it — stretching, compressing, warping — until one species mapped onto the bones of another.
The Cartesian Deformation
Thompson's insight was that the forms of organisms could be explained not solely by natural selection, but by physical forces acting upon growing tissue. Where Darwin saw adaptation, Thompson saw geometry — and his transformation grids remain among the most elegant demonstrations in all of biological science.
The form of an object is a diagram of forces; in this sense, the study of form becomes inseparable from the study of the forces which have acted upon it.