Chapter 3
The Biological Basis of Behavior
Terms
undefined, object
copy deck
- mutation
- spontaneous, heritable change in a piece of DNA that occurs in an individual organism
- natural selection
- heritable characteristics that provide a reproductive advantage are more likely than alternative characteristics to be passed on to subsequent generations and come to be "selected" over time
- split-brain surgery
- the bundle of fibers that connects the cerebral hemispheres (the corpus callosum) is cut to reduce the severity of epileptic seizures
- adoption studies
- assess hereditary influence by examining the resemblance betwenn aopted children and both their biological and adoptive parents
- parasympathetic division
- branch of the autonomic nervous system that conserves bodily resources
- thalamus
- structure in the forebrain through which all sensory info. (except smell) must pass to get to the cortex
- excitatory PSP
- positive voltage shift that increases the likelihood that the postsynaptic neuron will fire action potentials
- postsynaptic potential
- voltage change at a receptor site on a postsynaptic cell membrane
- action potential
- brief shift in a neurons electrical charge that travels along an axon
- autonomic nervous system
- made up of nerves that connect to the heart, blood vessels, smooth muscles, and glands
- absolute refractory period
- minimum length of time after a action potential during which another action potential cant begin
- endorphins
- internally produced chemical that resemble opiates in structure and effects
- twin studies
- when researchers assess hereditary influence by comparing the resemblance of identical twins and fraternal twins with respect to a trait
- central nervous system
- brain and spinal cord
- corpus callosum
- structure that connects two cerebral hemisphere
- synapse
- junction where information is transmitted from one neuron to another
- recessive gene
- one that is masked when paired genes are different
- adaption
- inherited characteristics that increased in a population ( through natural selection) because it helped solve a problem of survival or reproduction during the time it emerged
- neurotransmitter
- chemicals that transmit information from one neuron to another
- agonist
- chemical that mimics the action of a neurotransmitter
- peripheral nervous system
- made up of all the nerves that lie outside the brain and spinal cord
- neurons
- individual cells in the nervous system that receive, integrate, and transmit in formation
- resting potential
- neurons, stable negative charge when the cell is inactive
- afferent nerve fibers
- axons that carry in formation inward to the central nervous system from the periphery of the body
- polyandry
- mating system in which each female seeks to mate with multiple males, whereas each male mates with only one female
- genotype
- genetic makeup
- polygenetic traits
- characteristics that are influenced by more than one pair of genes
- myelin sheath
- insulating material derived from glial cells' that encases some axons
- reuptake
- process in which neurotransmitters are sponged up from the synaptic cleft by the presynaptic membrane
- endocrine system
- consists of glands that secrete chemicals into the blood-stream that help control bodily functioning
- forebrain
- largest and most complex region of the brain, encompassing a variety of structures including the thalamus, hypothalamus, limbic system, and cerebrum
- electroencephalograph
- device that monitors the electrical activity of the brain over time by means of recording electrodes attached to the surface of the scalp
- phenotype
- refers to the ways in which a persons genotype is manifested in observable charcteristics
- hormones
- chemical substances released by the endocrine glands
- genes
- DNA segments that serve as the key functional units in hereditary transmission
- homozygous condition
- two genes in a specific pair are the same
- monogamy
- matins system in which one male and one female mate exclusively or almost exclusively with each other
- electrical stimulation of the brain (ESB)
- sending a weak electric current into a brain structure to activate it
- synaptic cleft
- microscopic gap between the terminal button of one neuron and the cell membrane of another neuron
- hindbrain
- includes the cerebellum and two structures found in the lower part of the brainstem: the medulla and the pons
- efferent nerve fibers
- axons that carry informationoutward from the central nervous system to the periphery of the two body
- cerebral hemispheres
- right and left halves of the cerebrum
- perceptual asymmetries
- left-right imbalances between the cerebral hemispheres in the speed of visual or auditory processing
- parental invesment
- refers to what each sex has ti invest- in terms of time, energy, survival risk, and forgone opportunities to produce and nurture offspring
- cerebral cortex
- outer layer of the cerebrum
- midbrain
- segment of the brainstem that lies between the hindbrain and the forebrain
- inclusive fitness
- sum of an individuals own reproductive success plus the effects the organism has on the reproductive success of related others
- dendrites
- parts of the neuron that are specialized to receive information
- cerebrospinal fluid
- nourishes brain and provides a protective cushion for it
- genetic mapping
- process of determining the location anf chemical sequence if specific genes on specific chromosomes
- Identical twins
- comes from one zygote the splits for unknown reasons
- axon
- long, thin fiber that transmits signals away from the soma to other neurons or to muscles or glands
- polygyny
- mating system in which each male seeks to mate with multiple females, whereas each female mates with only one male
- chromosomes
- strands of DNA molecules that carry genetic information
- fraternal twins
- results when two eggs are fertilized simultaneously by different sperm cells, forming two seperate zygotes
- sympathetic division
- branch of the autonomic nervous system that mobilizes the bodys resources for emergencies
- nerves
- bundles of neuron fibers (axons) that are routed together in the peripheral nervous system
- somatic nervous system
- made up of nerves that connect to voluntary skeletal muscles and to sensory receptors
- heterozygous condition
- two genes in a specific pair are different
- lesioning
- destroyoing a piece of the brain
- hypothalamus
- structure found near the base of the forebrain that is involved in regulation of basic bioligical needs
- dominant gene
- one that is expressed when paired genes are different
- zygote
- a single cell formed by the union of a sperm and an egg
- soma
- (cell body) conatains cell nucleus and most of the chemical machinery common to most cells
- antagonist
- chemical that opposes the action of a neurotransmitter
- family studies
- when researchers assess hereditary influence by examining blood relatives to see how much they resemble one another on a specific trait
- terminal buttons
- small knobs that secrete neurtoransmitters
- inhibitory PSP
- negative voltage shift that decreases the likelihood that the postsynaptic neuron will fire action potentials
- pituitary gland
- releases a variety of hormones that fan out around the body, stimulating actions in the other endocrine glands
- limbic system
- loosely connected network of structures located along the boder between the cerebral cortex and deeper subcortical areas
- critical period
- limited time span in the development of an organism when it is optimal for certain capacities to emerge because the organism is especially responsive to certain experiences
- behavioral genetics
- an interdisciplinary field that studies the influence of genetic factors on behavioral traits
- fitness
- the reproductive success (number of descendants) of an individual organism relative to the average reproductive success in the population