Human sociobiology, the study of behavioral ecology in humans, is a comprative science. The same theoretical concepts can be applied to the evolution of social behavior in very different spicies.

If we review insect and vertebrate societies, altruism in bees, birds, and mammals could be explained with the same concept of kin selection. We could then agree that social behavior has a biological basis, and that one unifying theory of evolution can explain it. But are humans just another social animal whose behavior can be explained and fully understood with Darwinian concepts?

As a social species, human have an unparalleled complexity. Indeed, we are the only species with the intelligence to conteplate the social behavior of other animals. Intellegence is just one human trait.

If an ethologist were to take an inventory of human behavior, he or she would list kin-selected altruism, reciprocity and other elaborate social contracts, extensive parental care, conflicts between parents and offsprings, violence, and warfare; variety of mating systems including monogamy, polygyny, and polyandry, along with sexual behaviors such as extra-pair copulation ("adultery") and homosexuality; and behaviors like adoption that appear to defy evolutionary explanation.

This incredible variety of behaviors occurs in one species, and any trait can change within any individual.

Are these behaviors rooted in human biology?

During the course of human evolution and the emergence of civilization, two processes led to adaptive change. One is biological evolution. We have a primate heritage, reflected in the extensive sharing of genetic material between humans and our closest relatives the ------------ Note: (I refuse to acknowledge that humans are related to any kind of animal, no matter what science say about that, and that is the reason for the blank),(FE-DT). Our upright posture, bipedal locomotion, and powerful, precise hand grips are adaptations whose origins are traceable through primate ancestors, some scientiest claim. Kin-selected and reciprocal altruism, as well as other shared traits like aggression and different types of mating systems, can also be seen in nonhuman primates, in whom we can demonstrate that these social traits are adaptive.