chapter 3: biology and behavior Flashcards
genome
the complete set of DNA of any organism, including all of its genes
genotype
the genetic material an individual inherits
phenotype
the observable expression of the genotype, including both body characteristics and behavior
environment
every aspect of individuals and their surroundings other than genes
chromosomes
molecules of DNA that transmit genetic information; chromosomes are made up of DNA
DNA (deoxyribonucleic acid)
molecules that carry all the biochemical instructions involved in the formation and functioning of an organism
genes
sections of chromosomes that are the basic unit of heredity in all living things
crossing over
the process by which sections of DNA switch from one chromosome to the other; crossing over promotes variability among individuals
mutation
a change in a section of DNA
sex chromosomes
the chromosomes (X and Y) that determine an individual’s designated sex at birth
endophenotypes
intermediate phenotypes, including the brain and nervous systems, that do not involve overt behavior
regulator genes
genes that control the activity of other genes
alleles
two or more different forms of a gene
dominant allele
the allele that, if present, gets expressed
recessive allele
the allele that is not expressed if a dominant allele is present
homozygous
having two of the same allele for a trait
heterozygous
having two different alleles for a trait
polygenic inheritance
inheritance pattern in which traits are governed by more than one gene
phenylketonuria (PKU)
a disorder related to a defective recessive gene on chromosome 12 that prevents metabolism of the amino acid phenylalanine
carrier genetic testing
genetic testing used to determine whether prospective parents are carriers of specific disorders
prenatal testing
genetic testing used to assess the fetus’ risk for genetic disorders
newborn screening
tests used to screen newborn infants for a range of genetic and non-genetic disorders
epigenetics
the study of stable changes in gene expression that are mediated by the environment
behavior genetics
the science concerned with how variation in behavior and development results from the combination of genetic and environmental factors
heritable
refers to characteristics or traits that are genetically transmitted
heritability
a statistical estimate of the proportion of the measured variance on a trait among individuals in a given population that is attributable to genetic differences among those individuals
neurons
cells that are specialized for sending and receiving messages between the brain and all parts of the body, as well as within the brain itself
cell body
a component of the neuron that contains the basic biological material that keeps the neuron functioning
dendrites
neural fibers that receive input from other cells and conduct it toward the cell body in the form of electrical impulses
axons
neural fibers that conduct electrical signals away from the cell body to connections with other neurons
synapses
microscopic junctions between the axon terminal of one neuron and the dendritic branches or cell body of another
glial cells
cells in the brain that provide a variety of critical supportive functions
myelin sheath
a fatty sheath that forms around certain axons in the body and increases the speed and efficiency of information transmission
cerebral cortex
the “gray matter” of the brain, consisting of four distinct lobes
occipital lobe
major area of the cortex that is primarily involved in processing visual information
temporal lobe
major area of the cortex that is associated with speech and language, music, and emotional information
parietal lobe
major area of the cortex that is associated with spatial processing and sensory information integration
frontal lobe
major area of the cortex that is associated with working memory and cognitive control
association areas
parts of the brain that lie between the major sensory and motor areas and that process and integrate input from those areas
cerebral hemispheres
the two halves of the cortex
corpus callosum
a dense tract of nerve fibers that enable the two hemispheres of the brain to communicate
cerebral lateralization
the specialization of the hemispheres of the brain for different modes of processing
neurogenesis
the proliferation of neurons through cell division
arborization
formation of new dendritic trees and branches
spines
formations on the dendrites of neurons that increase the dendrites’ capacity to form connections with other neurons
myelination
the formation of myelin (a fatty sheath) around the axons of neurons that speeds and increases information-processing abilities
synaptogenesis
the process by which neurons form synapses with other neurons, resulting in trillions of connections
synaptic pruning
the normal developmental process through which synapses that are rarely activated are eliminated
plasticity
the capacity of the brain to be affected by experience
experience-expectant plasticity
the process through which the normal wiring of the brain occurs in part as a result of species-typical experiences
experience-dependent plasticity
the process through which neural connections are created and reorganized throughout life as a function of an individual’s experiences
secular trends
marked changes in physical development that have occurred over generations
