The Augustinian friar in Brno who found the arithmetic of heredity by growing and counting roughly 28,000 pea plants between 1856 and 1863. Mendel showed that traits pass not by blending but as discrete factors — one drawn from each parent — with dominant forms masking recessives in a steady 3-to-1 ratio. His 1866 paper was ignored for thirty-four years. Around 1900 three botanists independently rediscovered it and founded Mendelism. In 1936 R. A. Fisher noted that Mendel’s ratios fit theory suspiciously well; the debate over his data remains unresolved.
A monk in a monastery garden counted peas until he found a law. Between 1856 and 1863, Gregor Mendel grew and tracked some twenty-eight thousand pea plants, recording whether each was tall or short, its seeds round or wrinkled, its flowers one color or another. He did what no naturalist had thought to do. He counted the offspring and did the arithmetic. The numbers came back in steady ratios, close to three to one, generation after generation. From them he reasoned that traits pass not as a blended fluid but as discrete units, one drawn at random from each parent, hidden forms able to vanish for a generation and return unchanged. He had found the basic rules of heredity. Almost no one noticed. His 1866 paper was largely ignored for thirty-four years, and Mendel died an abbot, never knowing he had founded a science.