Chapter 3 Flashcards
Adaptation
An inherited characteristic that increased in a population (through natural selection) because it helped solve a problem of survival or reproduction during the time it emerged.
Adoption studies
Research studies that assess hereditary influence by examining the resemblance between adopted children and both their biological and their adoptive parents.
Agonist
A chemical that mimics the action of a neurotransmitter.
Antagonist
A chemical that opposes the action of a neurotransmitter.
Behavioural genetics
An interdisciplinary field that studies the influence of genetic factors on behavioural traits.
Critical period
A 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.
Dominant gene
A gene that is expressed when paired genes are heterozygous (different).
Electrical stimulation of the brain (ESB)
Sending a weak electric current into a brain structure to stimulate (activate) it.
Endorphins
The entire family of internally produced chemicals that resemble opiates in structure and effects.
Excitatory PSP
An electric potential that increases the likelihood that a postsynaptic neuron will fire action potentials.
Family studies
Scientific studies in which researchers assess hereditary influence by examining blood relatives to see how much they resemble each other on a specific trait.
Fitness
The reproductive success (number of descendants) of an individual organism relative to the average reproductive success of the population.
Forebrain
The largest and most complicated region of the brain, encompassing a variety of structures, including the thalamus, hypothalamus, limbic system, and cerebrum.
Genes
DNA segments that serve as the key functional units in hereditary transmission.
Genetic mapping
The process of determining the location and chemical sequence of specific genes on specific chromosomes.
Genotype
A person’s genetic makeup.
Heterozygous condition
The situation that occurs when two genes in a specific pair are different.
Hindbrain
The part of the brain that includes the cerebellum and two structures found in the lower part of the brainstem: the medulla and the pons.
Homozygous condition
The situation that occurs when two genes in a specific pair are the same.
Inclusive fitness
The sum of an individual’s own reproductive success plus the effects the organism has on the reproductive success of related others.`
Inhibitory PSP
An electric potential that decreases the likelihood that a postsynaptic neuron will fire action potentials.
Lesioning
Destroying a piece of the brain.
Limbic system
A densely connected network of structures roughly located along the border between the cerebral cortex and deeper subcortical areas.
Midbrain
The segment of the brain stem that lies between the hindbrain and the forebrain.
Mutation
A spontaneous, heritable change in a piece of DNA that occurs in the individual organism.
Natural selection
Principle stating that heritable characteristics that provide a survival reproductive advantage are more likely than alternative characteristics to be passed on to subsequent generations and thus come to be “selected” over time.
Perceptual asymmetries
Left–right imbalances between the cerebral hemispheres in the speed of visual or auditory processing.
Phenotype
The ways in which a person’s genotype is manifested in observable characteristics.
Polygenic traits
Characteristics that are influenced by more than one pair of genes.`
Postsynaptic potential (PSP)
A voltage change at the receptor site on a postsynaptic cell membrane.
Recessive gene `
A gene whose influence is masked when paired genes are different (heterozygous).`
Split-brain surgery
A procedure in which the bundle of fibres that connects the cerebral hemispheres (the corpus callosum) is cut to reduce the severity of epileptic seizures.
Twin studies
A research design in which hereditary influence is assessed by comparing the resemblance of identical twins and fraternal twins with respect to a trait.
