Pea diminish leaf and stem growth. Adult weevils feed on the leaves and create a notched, "c-shaped" appearance on the outside of the leaves. In the mid-19th century, Austrian monk Gregor Mendel's observations of pea pods led to the principles of Mendelian genetics, the foundation of modern genetics. He ended up growing and examining about 28,000 pea plants in the course of his experiments. Mendel chose peas for his experiments because he could grow them easily, develop pure-bred strains, protect them from cross-pollination, and control their pollination. Mendel cross-bred tall and dwarf pea plants, green and yellow peas, purple and white
Natural selection used by Mr. Herbert Spencer of the Survival of the Fittest is more accurate, and is sometimes equally convenient." Although the phrase is still often used by non-biologists, modern biologists avoid it because it is tautological if "fittest" is read to mean "functionally superior" and is applied to individuals rather than considered as an averaged quantity over populations. Natural selection relies crucially on the idea of heredity, but developed before the basic concepts of genetics. Although the Moravian monk Gregor Mendel, the father of modern genetics, was a contemporary of Darwin's, his work lay in obscurity, only being rediscovered in