PSY Module 6

Genes are the biochemical units of heredity that make up chromosomes, the threadlike coils of DNA. When genes are "turned on" (expressed), they provide the code for creating the proteins that form our body's building blocks. Most human traits are influenced by many genes acting together. The human genome is the shared genetic profile that distinguishes humans from other species, consisting at an individual level of all the genetic material in an organism's chromosomes. Behavior geneticists study the relative power and limits of genetic (our heredity) and environmental influences on behavior.

every nongenetic influence, from prenatal nutrition to the people and things around us.

the study of the relative power and limits of genetic and environmental influences on behavior

the genetic transfer of characteristics from parents to offspring

threadlike structures made of DNA molecules that contain the genes

a complex molecule containing the genetic information that makes up the chromosomes

the biochemical units of heredity that make up the chromosomes; segments of DNA capable of synthesizing proteins

the complete instructions for making an organism, consisting of all the genetic material in that organism's chromosomes

gene, chromosome, nucleus

chromosomes

Studies of identical (monozygotic) twins versus fraternal (dizygotic) twins, separated twins, and biological versus adoptive relatives allow researchers to tease apart the influences of heredity and environment. Research studies on separated identical twins maintain the same genes while testing the effects of different home environments. Studies of adoptive families let researchers maintain the same home environment while studying the effects of genetic differences. Heritable individual differences (in traits such as height and weight) do not necessarily explain gender or ethnic group differences. Shared family environments have little effect on personality, though parenting does influence other factors (such as attitudes).

develop from a single fertilized egg that splits in two, creating two genetically identical organisms

develop from separate fertilized eggs. They are genetically no closer than ordinary brothers and sisters, but they share a prenatal environment

Researchers use twin and adoption studies to understand how much variation among individuals is due to genetic makeup and how much to environmental factors. Some studies compare the traits and behaviors of identical twins (same genes) and fraternal twins (different genes, as in any two siblings). They also compare adopted children with their adoptive and biological parents. Some studies compare traits and behaviors of twins raised together or separately.

Our genetic predispositions and our specific environments interact. Environments can trigger or block genetic expression, and genetically influenced traits can evoke responses from others. The field of epigenetics studies the influences on gene expression that occur without changes in DNA.

the study of environmental influences on gene expression that occur without a DNA change. Study of environmental factors that affect how our genes are expressed.

Evolutionary psychologists seek to understand how our traits and behavior tendencies are shaped by natural selection, as genetic variations increasing the odds of reproducing and surviving in their particular environment are most likely to be passed on to future generations. Some variations arise from mutations (random errors in gene replication), others from new gene combinations at conception. Humans share a genetic legacy and are predisposed to behave in ways that promoted our ancestors' surviving and reproducing. Charles Darwin's theory of evolution is an organizing principle in biology. He anticipated today's application of evolutionary principles in psychology.

the study of the evolution of behavior and the mind, using principles of natural selection

the principle that those chance inherited traits that better enable an organism to survive and reproduce in a particular environment will most likely be passed on to succeeding generations

a random error in gene replication that leads to a change

Over multiple generations, Belyaev and Trut selected and bred foxes that exhibited a trait they desired: tameness. This process is similar to naturally occurring selection, but it differs in that natural selection is much slower, and normally favors traits (including those arising from mutations) that contribute to reproduction and survival.

the interplay that occurs when the effect of one factor (such as environment) depends on another factor (such as heredity).

gene

two eggs are fertilized by two sperm.

environments

differences, commonalities

natural selection of the fittest adaptations.

protein molecules

mutations

epigenetic marks

natural selection

a mutation

values

epigenetics

99.9%

evolutionary psychology