| A | B |
|---|
| Behavior genetics | the study of the relative power and limits of genetic and environmental influences on behavior. |
| Environment | every non-genetic influence, from prenatal nutrition to the people and things around us. |
| Chromosomes | threadlike structures made of DNA molecules that contain the genes. |
| DNA | a complex molecule containing the genetic information that makes up the chromosomes. |
| Genes | the biochemical units of heredity that make up the chromosomes; segments of DNA capable of synthesizing a protein. |
| Genome | the complete instructions for making an organism, consisting of all the genetic material in that organism’s chromosomes. |
| Heritability | the proportion of variation among individuals that we can attribute to genes. The heritability of a trait may vary, depending on the range of populations and environments studied. |
| Identical Twins | develop from a single fertilized egg that splits in two, creating two genetically exact organisms. |
| Fraternal Twins | develop from separate fertilized eggs. They are genetically no closer than brothers and sisters, but they share a fetal environment. |
| Interaction | the interplay that occurs when the effect of one factor (such as environment) depends on another factor (such as heredity). |
| Molecular Genetics | the subfield of biology that seeks to identify specific genes influencing behavior and the structure and function of those genes. |
| Evolutionary Psychology | the study of the changes in behavior and the mind that have taken place during mankind’s history using the principles of natural selection |
| Natural Selection | the principle that, among the range of inherited trait variations, those that lead to increased reproduction and survival will most likely be passed on to succeeding generations. |
| Mutation | the random error in gene replication that leads to a change. |
