Chapter 3: Biology and Behavior

Question 1

alleles

Answer 1

two or more different forms of a gene

Question 2

association areas

Answer 2

parts of the brain that lie between the major sensory and motor areas and that process and integrate input from those areas

Question 3

axons

Answer 3

neural fibers that conduct electrical signals away from the cell body to connections with other neurons

Question 4

behavior genetics

Answer 4

the science concerned with how variation in behavior and development results from the combination of genetic and environmental factors

Question 5

cell body

Answer 5

a component of the neuron that contains the basic biological material that keeps the neuron functioning

Question 6

cerebral cortex

Answer 6

the “grey matter” of the brain that plays a primary role in what is thought to be particularly humanlike functioning, from seeing and hearing to writing to feeling emotion

Question 7

cerebral hemispheres

Answer 7

the two halves of the cortex; for the most part, sensory input from one side of the body goes to the opposite hemisphere of the brain

Question 8

cerebral lateralization

Answer 8

the specialization of the hemispheres of the brain for different modes of processing

Question 9

chromosomes

Answer 9

molecules of DNA that transmit genetic information; chromosomes are made up of DNA

Question 10

corpus callosum

Answer 10

a dense tract of nerve fibers that enable the two hemispheres of the brain to communicate

Question 11

crossing over

Answer 11

the process by which sections of DNA switch from one chromosome to the other; crossing over promotes variability among individuals

Question 12

dendrites

Answer 12

neural fibers that receive input from other cells and conduct it toward the cell body in the form of electrical impulses

Question 13

DNA (deoxyribonucleic acid)

Answer 13

molecules that carry all the biochemical instructions involved in the formation and functioning of an organism

Question 14

dominant allele

Answer 14

the allele that, if present, gets expressed

Question 15

environment

Answer 15

every aspect of an individual and his or her surroundings other than genes

Question 16

event-related potentials (ERPs)

Answer 16

changes in the brain’s electrical activity that occur in response to the presentation of a particular stimulus

Question 17

experience-dependent plasticity

Answer 17

the process through which neural connections are created and reorganized throughout life as a function of an individual’s experiences

Question 18

experience-expectant plasticity

Answer 18

the process through which the normal wiring of the brain occurs in part as a result of experiences that every human who inhabits any reasonably normal environment will have

Question 19

failure to thrive (nonorganic)

Answer 19

a condition in which infants become malnourished and fail to grow or gain weight for no obvious medical reason

Question 20

frontal lobe

Answer 20

associated with organizing behavior; the one that is thought responsible for the human ability to plan ahead

Question 21

genes

Answer 21

sections of chromosomes that are the basic unit of heredity in all living things

Question 22

genome

Answer 22

the complete set of genes of any organism

Question 23

genotype

Answer 23

the genetic material an individual inherits

Question 24

glial cells

Answer 24

cells in the brain that provide a variety of critical supportive functions

Question 25

heritability

Answer 25

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

Question 26

heritable

Answer 26

refers to any characteristics or traits that are influenced by heredity

Question 27

heterozygous

Answer 27

having two different alleles for a trait

Question 28

homozygous

Answer 28

having two of the same allele for a trait

Question 29

lobes

Answer 29

major areas of the cortex associated with general categories of behavior

Question 30

multifactorial

Answer 30

refers to traits that are affected by a host of environmental factors as well as genetic ones

Question 31

mutation

Answer 31

a change in a section of DNA

Question 32

myelin sheath

Answer 32

a fatty sheath that forms around certain axons in the body and increases the speed and efficiency of information transmission

Question 33

myelination

Answer 33

the formation of myelin (a fatty sheath) around the axons of neurons that speeds and increases information-processing abilities

Question 34

neurogenesis

Answer 34

the proliferation of neurons through cell division

Question 35

neurons

Answer 35

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

Question 36

norm of reaction

Answer 36

all the phenotypes that can theoretically result from a given genotype in relation to all the environments in which it can survive and develop

Question 37

occipital lobe

Answer 37

the lobe of the cortex that is primarily involved in processing visual information

Question 38

parietal lobe

Answer 38

governs spatial processing as well as integrating sensory input with information stored in memory

Question 39

phenotype

Answer 39

the observable expression of the genotype, including both body characteristics and behavior

Question 40

phenylketonuria (PKU)

Answer 40

a disorder related to a defective recessive gene on chromosome 12 that prevents metabolism of phenylalanine

Question 41

plasticity

Answer 41

the capacity of the brain to be affected by experience

Question 42

polygenic inheritance

Answer 42

inheritance in which traits are governed by more than one gene

Question 43

recessive allele

Answer 43

the allele that is not expressed if a dominant allele is present

Question 44

regulator genes

Answer 44

genes that control the activity of other genes

Question 45

secular trends

Answer 45

marked changes in physical development that have occurred over generations

Question 46

sex chromosomes

Answer 46

the chromosomes (X and Y) that determine an individual's gender

Question 47

spines

Answer 47

formations on the dendrites of neurons that increase the dendrites' capacity to form connections with other neurons

Question 48

synapses

Answer 48

microscopic junctions between the axon terminal of one neuron and the dendritic branches or cell body of another

Question 49

synaptic pruning

Answer 49

the normal developmental process through which synapses that are rarely activated are eliminated

Question 50

synaptogenesis

Answer 50

the process by which neurons form synapses with other neurons, resulting in trillions of connections

Question 51

temporal lobe

Answer 51

the lobe of the cortex that is associated with memory, visual recognition, and the process of emotion and auditory information