1.1 - 1.2 Vocab

heredity

The genetic transmission of characteristics from biological parents to offspring.

environment

Every non-genetic influence on a person, from prenatal nutrition to culture and social experience.

genes

The biochemical units of heredity, made of DNA, that direct the production of proteins

chromosomes

Threadlike structures in the cell nucleus, made of DNA, that carry the genes.

DNA

The complex molecule that makes up chromosomes and carries genetic instructions.

genome

The complete set of genetic instructions for building a particular organism.

genetic predisposition

An inherited tendency that makes a particular trait or disorder more likely to develop, given certain conditions.

identical twins

Siblings who developed from a single fertilized egg that split, giving them essentially the same genes.

fraternal twins

Siblings who developed from two separately fertilized eggs and share about half their genes, like any siblings.

twin studies

Research comparing similarities between identical and fraternal pairs to estimate genetic and environmental contributions.

adoption studies

Research comparing adopted children with their biological and adoptive relatives to separate genetic from environmental influence.

family studies

Research examines whether a trait runs in families and how strongly relatedness predicts sharing it.

heritability

The proportion of variation among individuals in a group that can be attributed to genetic differences.

interaction

The effect that occurs when the influence of one factor depends on the presence

or level of another factor.

epigenetics

The study of environmental influences that switch genes on or off without altering the underlying DNA sequence.

mutation

A random change in a DNA sequence that produces a new variation, which natural selection may then act on.

eugenics

The discredited movement that sought to improve a population's genetic makeup through controlled reproduction.

temperament

A person's characteristic emotional reactivity and intensity, evident very early in life and largely biologically based.

evolutionary psychology

The study of how natural selection shaped behavior and mental processes that are common across the species.

nervous system

The body's fast electrochemical communication network, consisting of all the nerve cells of the central and peripheral divisions.

central nervous system

The division of the nervous system consisting of the brain and spinal cord.

peripheral nervous system

The division of the nervous system made up of the nerves that connect the brain and spinal cord to the rest of the body.

somatic nervous system

The division of the peripheral system that carries sensory input and controls the voluntary movements of skeletal muscles.

autonomic nervous system

The division of the peripheral system that controls glands and the muscles of internal organs, largely outside conscious control.

sympathetic nervous system

The autonomic division that arouses the body and mobilizes energy in response to threat or stress.

parasympathetic nervous system

The autonomic division that calms the body and conserves energy after arousal has passed.

sensory neurons

Nerve cells that carry incoming information from sensory receptors to the brain and spinal cord.

motor neurons

Nerve cells that carry outgoing instructions from the central nervous system to muscles and glands.

interneurons

Nerve cells within the brain and spinal cord that link sensory input to motor output and process information along the way

nerves

Bundled cables of axons that connect the central nervous system with muscles, glands, and sense organs.

reflex

A simple, automatic response to a sensory stimulus that is processed by the spinal cord rather than the brain.

reflex arc

The neural pathway of a simple automatic response, running from sensory neuron to interneuron to motor neuron.

spinal cord

The bundle of neural tissue running from the brainstem down the back that carries messages and controls simple reflexes.

neural network

An interconnected cluster of nerve cells that strengthens with use and processes information as a working unit.

glial cells

Support cells in the nervous system that nourish, insulate, and protect neurons and assist in information transmission.