Physiological Basis of Human Behavior Essay

Heredity is the passing of traits to offspring from its parents or ancestor. This is the process by which an offspring cell or organism acquires or becomes predisposed to the characteristics of its parent cell or organism. Through heredity, variations exhibited by individuals can accumulate and cause some species to evolve. The study of heredity in biology is called genetics, which includes the field of epigenetics. Both hereditary and hormones affect human behavior but in different ways. It is a combination of these two factors which results in â€Å"normal† behavior. Heredity and hormones work together to influence behavior. Heredity includes genetics, behavioral genetics, and evolutionary psychology; while hormones are produced by the endocrine system, in concert with the nervous system. Hormones switch on behaviors. Looking at the relationships between hormones and heredity provides a complete picture of the effects of heredity on human behavior. Genetics is the study of how traits are passed from one generation to the next through genes, which are found on chromosomes. They are a small part of DNA, and they direct particular traits of groups of traits. They are the essence of a human being, their make-up, and they are unmodifiable. They are carried by tiny threadlike bodies called chromosomes. They vary in size and shape and they come in pairs. Genes are responsible for the development of the nervous and endocrine systems; therefore, genes can influence the chance of a certain behavior occurring in a certain set of circumstances. They are indirect to behavior, while hormones are direct. Genes are most often considered in a physiological manner, as in whether one is predisposed to being tall or short, or being blonde haired or blue eyed. Behavior genetics are the other side of genetics, more specifically how genes can be considered to pass on psychological traits rather than physiological ones. Each species has a constant number of chromosomes that never varies, weight, height, skin color and many other traits are produced by the interaction of several genes. This process is called polygenic inheritance, and each of the genes contributes individually to the overall effect. As the chromosomes carries the genes, so does the bloodstream, hormones.