Evolution of a Linear Molecule

Evolutionary biologists used hand drawn diagrams to illustrate how an organism might move through the almost infinite field of possible variations. The horizontal axes plot the variability in d and a, a k a geno types or physical traits. The more similar two variants are, the close they sit on the plane. Variants that improve an organism's odds of surviving, whether by increasing its violable offspring or improving the function of its proteins, perch on peaks while those that diminish their chances languish in valleys.