Question 1

Type I rhodopsins:

Accepted Answer

A)  are only found in prokaryotes. 
B)  are converted from 11-cis to all-trans retinal isomers by light. 
C)  can be used experimentally either to photo-activate or -inactivate mammalian neurons. 
D)  are closely related to type II rhodopsins in sequence and structure. 
E)  All of the above 
A)  are only found in prokaryotes. 
B)  are converted from 11-cis to all-trans retinal isomers by light. 
C)  can be used experimentally either to photo-activate or -inactivate mammalian neurons. 
D)  are closely related to type II rhodopsins in sequence and structure. 
E)  All of the above

Question 2

What evidence best supports the independent gain of gyri and sulci in neocortex multiple times in the mammalian lineage?

Accepted Answer

A)  Species in all three branches of mammals (monotremes, marsupials, and placental mammals) have gyri and sulci. 
B)  Species in all three branches of mammals (monotremes, marsupials, and placental mammals) lack gyri and sulci. 
C)  Reptiles, the outgroup of mammals, do not have gyri, sulci, or neocortex. 
D)  Larger mammalian brains are more likely to have gyri and sulci. 
E)  Smaller mammalian brains are less likely to have gyri and sulci. 
A)  Species in all three branches of mammals (monotremes, marsupials, and placental mammals) have gyri and sulci. 
B)  Species in all three branches of mammals (monotremes, marsupials, and placental mammals) lack gyri and sulci. 
C)  Reptiles, the outgroup of mammals, do not have gyri, sulci, or neocortex. 
D)  Larger mammalian brains are more likely to have gyri and sulci. 
E)  Smaller mammalian brains are less likely to have gyri and sulci.

Question 3

Hox genes are highly conserved players in anteroposterior patterning  and were named for the homeotic transformations exhibited by their mutants in Drosophila.   Figure 
A. The original Antp mutant has legs in place of antennae. Is this a gain- or loss-of-function mutation?
B. The original Ubx mutant has a second set of wings instead of halteres (flying organs normally found on the third thoracic segment). Is this a gain- or loss-of-function mutation?
C. Although the role of Hox genes in anteroposterior patterning is conserved in vertebrates, HoxA9-13 and D9-13 are used in proximodistal limb patterning. What evolutionary events made acquisition of this novel function possible?

Accepted Answer

Antennae do not normally express any of

Question 4

In clever experiments, expression of the human L-opsin gene was shown to be sufficient to improve spectral discrimination in both female mice and male squirrel monkeys.
A. Would male mice with the knocked-in human L-opsin gene be expected to perform spectral discrimination tasks as well as their heterozygous female siblings? Briefly explain your reasoning.
B. Would male squirrel monkeys with virally transduced human L-opsin be expected to perform spectral discrimination tasks as well as their heterozygous female siblings? Briefly explain your reasoning.
Evolution of Nervous System Structure and Development

Accepted Answer

No. Because male mice are hemizygous (po

Question 5

Some dragonfish (Stomiidae) family members have rod opsins tuned to short-wave (blue) wavelengths, which is a very common adaptation found in deep-sea fish. However, other dragonfish species both emit and detect long-wave (red) emissions. Use maximum parsimony analysis along with the phylogenetic tree in Figurein order to deduce when red color vision was lost and/or gained.   Figure

Accepted Answer

Based on this molecular phylog

Question 6

Which of the following is an example of a metazoan (animal) innovation?

Accepted Answer

A)  24TM Na+ channels 
B)  24TM Ca2+ channels 
C)  6TM K+ channels 
D)  2TM K+ channels 
E)  None of the above 
A)  24TM Na+ channels 
B)  24TM Ca2+ channels 
C)  6TM K+ channels 
D)  2TM K+ channels 
E)  None of the above

Question 7

Glial wrapping of axons:

Accepted Answer

A)  emerged once, prior to the vertebrate-invertebrate split. 
B)  reduces membrane resistance. 
C)  increases membrane capacitance. 
D)  speeds up conduction of action potentials. 
E)  All of the above 
A)  emerged once, prior to the vertebrate-invertebrate split. 
B)  reduces membrane resistance. 
C)  increases membrane capacitance. 
D)  speeds up conduction of action potentials. 
E)  All of the above

Question 8

Humans that are born blind or deaf depend more on their remaining senses and may even experience rewiring of the neocortex for other functions. This could explain why cochlear implants or hearing aids often do not work well in individuals who have experienced extended hearing loss prior to treatment.
A. What is the experimental evidence in ferrets for adaptive specialization of the neonatal neocortex?
B. Bats that use echolocation to identify prey have expanded areas in the auditory cortex specifically tuned to the ultrasonic frequencies that they emit, while non-echolocating bats do not. Describe an experiment that could demonstrate whether this difference is due to developmental plasticity of the properties of the neocortex.

Accepted Answer

The auditory axonal projections to the m

Question 9

Draw a parallel between gene duplication and cell duplication in the evolution of increasing specialization and complexity, and give an example of the latter.

Accepted Answer

A gene encoding a multifunctional produc

Question 10

Which of the following would be an example of convergent evolution?

Accepted Answer

A)  Neurons, synapses, and nerve nets emerged independently in the ctenophores (comb jellies) and in the eumetazoan lineage leading to bilaterians and cnidarians. 
B)  Neurons, synapses, and nerve nets emerged in the common ancestor of ctenophores (comb jellies), bilaterians, and cnidarians but were lost in the poriferans (sponges). 
C)  The centralization of neurons into brains and nerve cords occurred before the divergence of protostomes and deuterostomes. 
D)  All modern vertebrates feature a notochord inherited from a common chordate ancestor. 
E)  All of the above 
A)  Neurons, synapses, and nerve nets emerged independently in the ctenophores (comb jellies) and in the eumetazoan lineage leading to bilaterians and cnidarians. 
B)  Neurons, synapses, and nerve nets emerged in the common ancestor of ctenophores (comb jellies), bilaterians, and cnidarians but were lost in the poriferans (sponges). 
C)  The centralization of neurons into brains and nerve cords occurred before the divergence of protostomes and deuterostomes. 
D)  All modern vertebrates feature a notochord inherited from a common chordate ancestor. 
E)  All of the above

Question 11

Which of the following is an example of evolution as a result of selection acting on genetic variation?

Accepted Answer

A)  Achromatopsia (extreme sensitivity to light and lack of color vision) becomes widespread among individuals on an isolated island because a common ancestor carried a mutant gene. 
B)  A random mutation produces a novel odorant receptor that allows a fly to detect a specific fruit, allowing it to monopolize a new food source and produce more offspring. 
C)  In a small population of birds, more individuals that produce one song variant reproduce than those that produce a different song variant, just by chance. 
D)  Frog eggs that happen to be laid during a severe drought are much less likely to survive than their siblings that developed in a wetter month. 
E)  All of the above 
A)  Achromatopsia (extreme sensitivity to light and lack of color vision) becomes widespread among individuals on an isolated island because a common ancestor carried a mutant gene. 
B)  A random mutation produces a novel odorant receptor that allows a fly to detect a specific fruit, allowing it to monopolize a new food source and produce more offspring. 
C)  In a small population of birds, more individuals that produce one song variant reproduce than those that produce a different song variant, just by chance. 
D)  Frog eggs that happen to be laid during a severe drought are much less likely to survive than their siblings that developed in a wetter month. 
E)  All of the above

Question 12

How can natural selection explain both the loss and gain of color vision at different points in our evolutionary history?

Accepted Answer

Ancestral vertebrates had four cone opsi

Question 13

Fill in each of the blanks with the best word or phrase selected from the list below. Not all words or phrases will be used; each word or phrase should be used only once.
Genetic variation arises from random ____________-changes in DNA that insert, delete, or substitute one or more base pairs, resulting in a new ____________ (version of the gene). If this change results in a phenotype that gives the organism a reproductive advantage, the new allele is likely to ____________ in frequency in the population. The ____________ of an allele can be defined as the ratio of offspring (or grandchildren) produced by individuals of a certain genotype over the highest number produced by any genotype in the population. ____________ selection increases the frequency of alleles with higher fitness. In a ____________ population, allele frequency can also change over generations due to sampling error (because not all individuals produce the same number of offspring). This change in allele frequency by chance is called genetic ____________ and could in principle even lead to the ____________ (frequency of 1) of an allele with relatively low fitness.
allele large
decrease mutation
drift negative
fitness positive
fixation shift
increase small
Evolution of Neuronal Communication

Accepted Answer

Genetic variation arises from random mut

Type I rhodopsins:

What evidence best supports the independent gain of gyri and sulci in neocortex multiple times in the mammalian lineage?

Which of the following is an example of a metazoan (animal) innovation?

Glial wrapping of axons:

Draw a parallel between gene duplication and cell duplication in the evolution of increasing specialization and complexity, and give an example of the latter.

Which of the following would be an example of convergent evolution?

Which of the following is an example of evolution as a result of selection acting on genetic variation?

How can natural selection explain both the loss and gain of color vision at different points in our evolutionary history?

An Invitation to Neurobiology

Signaling Within Neurons

Signaling Across Synapses

Vision

Wiring of the Visual System

Olfaction, Taste, Audition, and Somatosensation

Wiring of the Nervous System

Motor and Regulatory Systems

Sexual Behavior

Memory, Learning, and Synaptic Plasticity

Brain Disorders

Ways of Exploring

Filters

Exam 12: Evolution of the Nervous System

Type I rhodopsins:

What evidence best supports the independent gain of gyri and sulci in neocortex multiple times in the mammalian lineage?

Which of the following is an example of a metazoan (animal) innovation?

Glial wrapping of axons:

Draw a parallel between gene duplication and cell duplication in the evolution of increasing specialization and complexity, and give an example of the latter.

Which of the following would be an example of convergent evolution?

Which of the following is an example of evolution as a result of selection acting on genetic variation?

How can natural selection explain both the loss and gain of color vision at different points in our evolutionary history?

An Invitation to Neurobiology

Signaling Within Neurons

Signaling Across Synapses

Vision

Wiring of the Visual System

Olfaction, Taste, Audition, and Somatosensation

Wiring of the Nervous System

Motor and Regulatory Systems

Sexual Behavior

Memory, Learning, and Synaptic Plasticity

Brain Disorders

Ways of Exploring

Filters