Evolution and Genes
Principles of Genetics
- Behavior geneticists study the genetic basis of behavior and personality differences among people.
- The more closely people are biologically related, the more genes they share.
- Traits can be monogenic (determined by one gene) or polygenic (determined by several genes).
- Researchers use heritability to determine how much of a trait’s variation within a population is due to genes.
Types of Genetic Studies
- Psychologists use family studies, twin studies, and adoption studies to see whether, and to what extent, characteristics are genetic.
- Heredity interacts with environment to influence psychological traits.
Evolution and Natural Selection
- Evolution is the change in the frequency of genes in a population.
- Charles Darwin proposed the theory of natural selection, which states that inherited characteristics that give an organism a survival or reproductive advantage are passed on more often to future generations than other inherited characteristics.
- An adaptation is an inherited characteristic that increases in a population because it provides a survival or reproductive advantage.
- Inclusive fitness is the reproductive fitness of an individual organism plus any effect that the organism has on increasing reproductive fitness in related organisms.
- Evolution relies on mutations, or small changes in genes.
- Evolutionary psychologists use evolutionary theory to explain patterns in psychological characteristics.
- Researchers study mating behavior to investigate aspects of evolutionary psychology.
- Parental investment refers to all the resources spent to produce and raise offspring.
- Sexual selection refers to the tendency of females to choose mates based on certain characteristics, which are then passed on to their male offspring.