Charles Robert Darwin, born in 1809, was an English naturalist who founded the theory of Darwinism, the belief in evolution as determined by natural selection. Although Darwin studied medicine at Edinburgh University, and then studied at Cambridge University to become a minister, he had been interested in natural history all his life. His grandfather, Erasmus Darwin, was a noted English poet, physician, and botanist who was interested in evolutionary development. Darwin's works have had an incalculable effect on all aspects of the modern thought. Darwin's most famous and influential work, On the Origin of Species, provoked immediate controversy. Darwin's other books include Zoology of the Voyage of the Beagle, The Variation of Animals and Plants Under Domestication, The Descent of Man, and Selection in Relation to Sex. Charles Darwin died in 1882.
Konrad Lorenz was an Austrian zoologist whose specialty, the biological origins of social behavior, is of major interest to psychologists. Lorenz pioneered in the direct study of animal behavior and was the founder of modern ethology (the study of animals in their natural surroundings). He received the Nobel Prize for physiology in 1973 for his research on instinctive behavior patterns and on imprinting---the process through which an animal very early in life acquires a social bond, usually with its parents, that enables it to become attached to other members of its own species. His major book, "On Aggression" (1963), was attacked by many anthropologists, psychologists, and sociologists, who maintained that Lorenz's claim that aggression is inborn means that it cannot be controlled. His supporters countered that Lorenz never stated that inborn traits could not be changed. Lorenz's work continues to play a key role in this contemporary version of the nature-nurture debate.