Heredity<span>, </span><span>the sum of all biological processes by which particular characteristics are transmitted from parents to their offspring. The concept of heredity encompasses two seemingly paradoxical observations about organisms: the constancy of a </span>species<span> from generation to generation and the </span>variation<span> among individuals within a species. Constancy and variation are actually two sides of the same coin, as becomes clear in the study of </span>genetics<span>. Both aspects of heredity can be explained by </span>genes<span>, the functional units of heritable material that are found within all living </span>cell<span>s. Every member of a species has a set of genes specific to that species. It is this set of genes that provides the constancy of the species. Among individuals within a species, however, variations can occur in the form each </span>genetic<span>s, providing the genetic basis for the fact that no two individuals (except identical twins) have exactly the same traits.</span>
an astonishing amount of behavioral variation is captured within the more than 350 breeds of dog recognized worldwide. Inherent in observations of dog behavior is the notion that much of what is observed is breed specific and will persist, even in the absence of training or motivation.
