4. Genetics, Evolution, Development and Plasticity Flashcards
Suppose you have high sensitivity to the taste of PTC. If your mother also has high sensitivity, what (if anything) can you predict about your father’s taste sensitivity?
a. He has high taste sensitivity.
b. He has low taste sensitivity.
c. We do not have enough information to make a prediction.
c. We do not have enough information to make a prediction.
Suppose you have high sensitivity to the taste of PTC. If your mother has low sensitivity, what (if anything) can you predict about your father’s taste sensitivity?
a. He has high taste sensitivity.
b. He has low taste sensitivity.
c. We do not have enough information to make a prediction.
a. He has high taste sensitivity.
What is a sex-limited gene?
a. A gene on the X chromosome
b. A gene on the Y chromosome
c. A gene that sex hormones activate
d. A gene that becomes active during sexual activity
c. A gene that sex hormones activate
Suppose someone identifies a “gene for” certain aspects of sexual development. In what ways might that statement be misleading?
a. The statement didn’t specify whether the gene was dominant or recessive.
b. Many aspects of sexual development are not apparent until puberty.
c. Almost any characteristic depends on many genes, as well as influences from the environment.
c. Almost any characteristic depends on many genes, as well as influences from the environment.
How does an epigenetic change differ from a mutation?
a. An epigenetic change is a duplication or deletion of part of a gene.
b. An epigenetic change is an alteration of gene activity without structurally replacing any part of the gene itself.
c. An epigenetic change alters more than one gene at a time.
d. An epigenetic change is beneficial, whereas a mutation is harmful.
b. An epigenetic change is an alteration of gene activity without structurally replacing any part of the gene itself.
How does adding a methyl or acetyl group to a histone protein alter gene activity?
a. A methyl group turns genes off. An acetyl group loosens histone’s grip and increases gene activation.
b. A methyl group turns genes on. An acetyl group tightens histone’s grip and decreases gene activation.
c. A methyl group increases the probability of a mutation, whereas an acetyl group decreases the probability.
d. A methyl group decreases the probability of a mutation, whereas an acetyl group increases the probability.
a. A methyl group turns genes off. An acetyl group loosens histone’s grip and increases gene activation.
Which of the following is NOT one of the main types of evidence to estimate the heritability of some behavior?
a. Comparisons between monozygotic and dizygotic twins
b. Similarities between adopted children and their biological parents
c. Examination of identified genes that might vary between people showing one behavior and another
d. Comparisons of people living in different cultures
d. Comparisons of people living in different culture
Suppose someone determines the heritability of IQ scores for a given population. Then society changes in a way that provides the best possible opportunity for everyone within that population. How will the heritability of IQ change, if at all?
a. Heritability will increase.
b. Heritability will decrease.
c. Heritability will stay the same.
a. Heritability will increase.
The information about phenylketonuria (PKU) supports which of these conclusions?
a. Several genes active in the human brain are not found in other species.
b. Each brain area controls a different behavioral function.
c. A change in the environment can alter the effects of a gene.
d. Epigenetic changes depend on methyl and acetate groups.
c. A change in the environment can alter the effects of a gene.
What, if anything, can we predict about the future of human evolution?
a. People will get smarter, wiser, and more cooperative.
b. People will not change, because evolution no longer affects humans.
c. People will become more like whichever people tend to have the most children.
c. People will become more like whichever people tend to have the most children.
Which of these is the least acceptable explanation for how an altruistic gene might spread in a population?
a. Selection for a gene that benefits the individuals’ relatives
b. Selection for helping individuals who might return the favor
c. Selection for genes that benefit the species
d. Selection for groups that are more cooperative than other groups
c. Selection for genes that benefit the species
Which part of a neuron forms first, if either?
a. The axon forms first.
b. The dendrites form first.
c. They form at the same time.
a. The axon forms first.
What is unusual about the olfactory receptors?
a. Olfactory neurons have more than one axon.
b. Humans do not begin forming olfactory neurons until nearly 2 years old.
c. We continue forming new olfactory neurons throughout life.
d. An unusually strong blood–brain barrier protects olfactory neurons from damage.
c. We continue forming new olfactory neurons throughout life.
The 14C concentration in the atmosphere has been declining since 1963. The 14C concentration in neurons of a person’s cerebral cortex and olfactory bulbs corresponds to that of ___.
a. the year of the person’s birth
b. about halfway between the person’s birth and the present year
c. the year the person’s education ended
d. the current year
a. the year of the person’s birth
When Sperry cut a newt’s optic nerve and turned the eye upside down, what happened?
a. Axons of the optic nerve grew randomly and attached diffusely to target cells in the tectum.
b. Axons of the optic nerve grew back to their original targets.
c. Axons of the optic nerve grew back to targets appropriate to their new location in the eye.
d. At first the axons grew back randomly, but then they established appropriate connections by learning.
b. Axons of the optic nerve grew back to their original targets.
If axons from the retina were prevented from showing spontaneous activity during early development, what would be the probable effect on development of the thalamus?
a. Axon attachment would be more precise than usual.
b. Axons would branch more widely, establishing more connections than usual.
c. Axons would not fine-tune their adjustment based on experience, so their connections would be less precise.
d. Axons would attach in the same way as usual, unaffected by the change.
c. Axons would not fine-tune their adjustment based on experience, so their connections would be less precise.
Why does the spinal cord have the right number of axons to innervate all the muscle cells?
a. Each muscle cell sends a chemical message telling the spinal cord to make a neuron.
b. The genes cause a certain number of neurons to form and the same number of muscles to form.
c. Immature cells divide, with one daughter cell becoming a neuron and the other becoming a muscle.
d. The spinal cord makes an excess of neurons, but those that fail to innervate a muscle die.
d. The spinal cord makes an excess of neurons, but those that fail to innervate a muscle die.
What is apoptosis?
a. A chemical that damages neurons
b. A chemical that keeps neurons alive
c. A programmed mechanism of cell death
d. A machine that records neuron activity
c. A programmed mechanism of cell death
Which neurons depend on nerve growth factor to prevent apoptosis in early development?
a. Neurons in the brain
b. Neurons in the sympathetic nervous system
c. Both
d. Neither
b. Neurons in the sympathetic nervous system
At what age does a person have the largest number of neurons?
a. Before or shortly after birth
b. Equally at all times of life
c. Adolescence
d. Adulthood
a. Before or shortly after birth
If a pregnant woman drinks alcohol, alcohol harms the brain of the fetus not only while it is in the system, but also while it is washing away after drinking. What is the danger while alcohol is washing away?
a. Temperature in the brain may decrease.
b. Blood pressure in the brain may decrease.
c. Excess inhibition at GABA synapses can lead to apoptosis.
d. Overstimulation at glutamate synapses can poison the mitochondria.
d. Overstimulation at glutamate synapses can poison the mitochondria.
In the ferret study, what evidence indicated that visual input to the auditory portions of the brain actually produced a visual sensation?
a. Bright flashes of light to the rewired eye caused the ferrets to blink both eyes.
b. Recordings from individual cells of the rewired temporal cortex showed the same patterns usually seen in cells of the occipital cortex.
c. Ferrets could find their way around an unfamiliar room even with the normal eye closed.
d. Ferrets that learned to turn one way in response to light in the normal eye turned the same way to light in the rewired eye.
d. Ferrets that learned to turn one way in response to light in the normal eye turned the same way to light in the rewired eye.
An enriched environment promotes growth of axons and dendrites in laboratory rodents. What is known to be one important reason for this effect?
a. Increased physical activity
b. Increased happiness
c. Increased relaxation
d. Increased empathy with other animals
a. Increased physical activity
If a person is born blind, in what way do the senses of hearing and touch improve?
a. The person gradually develops more receptors in the ears and skin.
b. The number of receptors does not change, but each of them becomes more responsive to weak stimuli.
c. The receptors in the ears and skin send faster action potentials to the brain.
d. Through practice the person learns to increase attention to hearing and touch, and those sensations come to activate the occipital cortex.
d. Through practice the person learns to increase attention to hearing and touch, and those sensations come to activate the occipital cortex.
Of the following, which is the strongest evidence to indicate that musical training modifies brain anatomy?
a. The gray matter of several cortical areas is thicker in professional musicians than in nonmusicians.
b. A larger than average portion of the right somatosensory cortex responds to the left hand in stringed instrument players than in other people.
c. At age 6, children starting musical training did not differ from average, but 15 months later they showed enlargements of several brain areas.
c. At age 6, children starting musical training did not differ from average, but 15 months later they showed enlargements of several brain areas.
Many studies report brain changes after special experiences in adulthood, such as learning to juggle or learning to play golf. Why are some researchers skeptical of these findings?
a. The adult brain cannot change anatomically.
b. Most of the reported results were small and have not been replicated.
c. Most of the reported studies had no control group.
d. Most of the reported studies required many years of training.
b. Most of the reported results were small and have not been replicated.
What causes musician’s cramp?
a. Changes in the muscles and tendons of the hand
b. Rewiring of the cerebral cortex
c. Loss of myelin on the motor nerves to the hand
d. Changes in the touch receptors of the hand
b. Rewiring of the cerebral cortex
Is it reasonable to argue that adolescents are mature enough to make some decisions and not others?
a. No. This argument is based entirely on political leanings.
b. Perhaps. Adolescents reason in a mature way for unimportant decisions, but not for important ones.
c. Perhaps. Adolescents reason in an immature way when they decide quickly under peer pressure.
d. Perhaps. Adolescents reason in a mature way when they are happy but not when they are sad.
c. Perhaps. Adolescents reason in an immature way when they decide quickly under peer pressure.
Immaturity of the prefrontal cortex is a possible explanation for which aspect of adolescent behavior?
a. Impulsivity
b. Increased interest in social contact
c. Increased appetite
d. Sleepiness during the day
a. Impulsivity
