ap psych unit 1 vocab (test 10/13)

nature-nuture issue

the long-standing debate over whether human behavior, personality, and development are shaped primarily by biological inheritance (nature) or by environmental experiences (nurture)

Charles Darwin

a British naturalist who proposed the theory of evolution by natural selection, which forms the core foundation for the evolutionary perspective in psychology

natural selection

the evolutionary process where traits that help an organism survive and reproduce are more likely to be passed on to future generations

evolutionary psychology

the study of how human thoughts, feelings, and behaviors are shaped by natural selection and survival over thousands of years.

behavior genetics

the study of the relative power and limits of genetic (nature) and environmental (nature) influences on behavior.

mutation

a random error in gene replication that leads to a permanent change in an organism’s DNA sequence.

environment

refers to every non-genetic, external influence on an individual’s thoughts, feelings, behaviors, and physical development; immediate physical and biological surroundings.

heredity

the genetic transfer of physical, behavioral, and mental traits form parents to offspring through DNA.

genes

the basic units of heredity. They determine traits passed from parents to offspring.

genome

an organism’s complete set of genetic material, including all of its genes and DNA sequences.

identical (monozygotic) twins

develop from a single fertilized egg that splits into two separate embryos, sharing 100% of their genetic material at conception.

fraternal (dizygotic) twins

siblings who develop from two separate eggs fertilized by two separate sperm cells during the same pregnancy. They share approximately 50% of their DNA, making them no more genetically alike than ordinary brothers or sisters born at different times.

interaction

the interplay or combined effect where the effect of one factor, such as biology or environment, depends on another factor, such as different environmental or genetic condition.

epigenetics

the study of environmental influences on gene expression that occur without an underlying change in the DNA sequence.

nervous system

the body’s rapid, electrochemical communication network. It consists of all the nerve cells that receive information from the environment and body, process it, and send out commands to the muscles and glands.

central nervous system (CNS)

the body’s primary decision-making and processing center, consisting of the brain and spinal cord.

peripheral nervous system (PNS)

the network of nerves located outside the brain and spinal cord that connects the Central Nervous System (CNS) to the rest of the body’s muscles, organs, and sensory receptors. The PNS relays messages from the CNS to the rest of the body, and it carries sensory information back in.

nerves

cable-like bundles of axons that belong to the Peripheral Nervous System (PNS) and connect the central nervous system to muscles, glands, and sense organs.

sensory (afferent) neurons

specialized nerve cells in the peripheral nervous system that carry signals from sensory receptors (in the skin, eyes, ears, nose, and tongue) toward the central nervous system (the brain and spinal cord).

motor (efferent) neurons

nerve cells that carry outgoing commands and instructions from the central nervous system (the brain and spinal cord) out to the body’s muscles and glands.

interneurons

neurons found only in the central nervous system (brain and spinal cord). They relay and process messages between sensory neurons and motor neurons, which makes them the middle link in a reflex arc.

somatic nervous system

the division of the peripheral nervous system that governs voluntary processes. It carries commands from the brain and spinal cord to your skeletal muscles so you can move on purpose, like raising your hand or kicking a ball

autonomic nervous system (ANS)

the part of the peripheral nervous system that controls involuntary processes like heart rate, breathing, and digestion, and it splits into the sympathetic (arousing) and parasympathetic (calming) nervous systems.

sympathetic nervous system

the autonomic branch that prepares your body for action by raising heart rate, breathing, blood pressure, and energy use; the classic fight-or-flight system.

parasympathetic nervous system

the branch of the autonomic nervous system that conserves energy and calms the body ('rest and digest') by slowing heart rate, slowing breathing, and increasing digestion and gland activity, the opposite of the sympathetic fight-or-flight response.

reflex

an involuntary response that happens without conscious thought or effort. Reflexes help keep internal organs functioning properly and protect the body from harm.

neuron

a nerve cell built to pass messages. It receives signals through its dendrites, processes them in the cell body (soma), and sends a signal down its axon to the terminal buttons.

cell body

the main part of a neuron that contains the nucleus and keeps the cell alive. It sits between the dendrites and the axon, and it contains the nucleus plus the organelles that keep the neuron alive and working. Also called the soma.

dendrites

the branch-like structures of neurons that extend from the cell body (Soma). The dendrites receive neural impulses (electrical and chemical signals) from the axons of other neurons.

axon

the long, spider-thin, tail-like structures found on neurons (nerve cells). The axon carries signals (electric voltages) between the dendrites (the neuron's input sites) and the terminal buttons (the neuron's output sites that are at the very end of the axon).

myelin sheath

a fatty covering around some axons that insulates them and makes nerve signals travel faster.

glial cells (glia)

non-neuronal cells in the nervous system that support neurons by providing structure, insulation (myelin), communication, and waste transport. They don't fire action potentials themselves, but they keep neural transmission running smoothly.

action potential

an electrical charge that travels along an axon when a neuron transmits information.