Question 1

An example of a sex-linked trait is ____.
A) green eye color
B) red-green color vision deficiency
C) temperament
D) intelligence

Accepted Answer

Red-green color vision deficiency is an example of a sex-linked trait because the gene that controls color vision is located on the X chromosome. Males only have one X chromosome, so if they inherit a color vision deficiency gene, they will exhibit the trait. Females have two X chromosomes, so they are less likely to exhibit the trait unless they inherit the gene from both parents.

Question 2

Suppose that adopted children are more similar to their biological parents than their adoptive parents in their preferences for a flavor of ice cream. Which statement is true in this circumstance?
A) Heritability of this trait is high.
B) Preferences for ice cream are determined solely by the environment.
C) Flavors of ice cream are naturally selected.
D) Heritability of this trait is low.

Accepted Answer

If adopted children are more similar to their biological parents in their preferences for ice cream flavor, it suggests that there is a significant genetic component to this trait. This means that heritability, or the extent to which genes influence the trait, is high.

Question 3

Sex-limited genes are found on ____.
A) X chromosomes only
B) Y chromosomes only
C) X and Y chromosomes
D) any autosomal chromosomes

Accepted Answer

Sex-limited genes are not restricted to sex chromosomes; they can be located on any autosomal chromosome but their expression is limited to one sex.

Question 4

Which pair of sex chromosomes is found in a normal male mammal?
A) XX
B) XY
C) YY
D) YZ

Accepted Answer

Normal male mammals have one X and one Y sex chromosome, making their genotype XY.

Question 5

Breeding some animals selectively because they possess some desirable characteristic is called ____.
A) evolution
B) natural selection
C) artificial selection
D) artificial insemination

Accepted Answer

Selective breeding of animals is called artificial selection. This involves humans choosing which animals to breed in order to produce offspring with desirable traits such as increased milk production or more meaty muscle tissue. This process is different from natural selection, which is the process by which certain traits become more or less common in a population over time due to their survival and reproductive benefits. Artificial insemination is the process of introducing sperm into the reproductive tract of a female to achieve pregnancy without natural mating.

Question 6

Why do children with PKU develop intellectual disabilities?
A) Unmetabolized amino acids accumulate and affect the brain.
B) Essential axons lack myelin sheaths.
C) Dendrites and synapses fail to form in associative areas of the cortex.
D) Their immune systems do not fight off brain infections.

Accepted Answer

PKU is caused by a genetic defect that impairs the metabolism of the amino acid phenylalanine. Unmetabolized phenylalanine and its byproducts accumulate in the blood and brain of affected individuals. High levels of phenylalanine can cause damage to brain cells and interfere with neurotransmitter production, leading to intellectual disabilities.

Question 7

In general, biologists who speak of sex-linked genes are typically referring to genes on ____.
A) autosomal chromosomes
B) more than one chromosome
C) the X chromosome
D) the Y chromosome

Accepted Answer

Sex-linked genes are typically those genes that are located on the sex chromosomes (X and Y). However, most sex-linked genes are found on the X chromosome, as it is much larger than the Y chromosome and contains many more genes. Genes on the Y chromosome are usually involved in male-specific traits and development.

Question 8

Which of the following represents Lamarckian evolution?
A) "Survival of the fittest"
B) "Reproduction of the fittest"
C) "If you don't use it, you lose it"
D) "Look out for number one"

Accepted Answer

"If you don't use it, you lose it" is a key concept of Lamarckian evolution, which proposed that acquired traits during an organism's lifetime would be passed on to offspring. This idea has since been disproven, as genetic material determines an organism's traits and not how they use or don't use certain body parts.

Question 9

How is it possible to prevent the intellectual disabilities that are generally associated with PKU?
A) Through exercise
B) Through diet
C) Through drugs
D) Through exposure to bright light

Accepted Answer

PKU can be prevented by following a strict low phenylalanine diet, which limits the intake of phenylalanine from foods. This diet should begin as early as possible after birth and be maintained throughout life to prevent intellectual disabilities and other complications associated with PKU. Exercise, drugs, and exposure to bright light are not effective in preventing PKU.

Question 10

An evolutionary psychologist would likely be most interested in studying ____.
A) altruistic behavior of meerkats
B) cardiovascular function across species
C) anatomy of the rat brain
D) neurotransmitters in primates

Accepted Answer

Evolutionary psychology focuses on how behaviors have evolved over time through natural selection. Altruistic behavior, such as that seen in meerkats, is a prime example of a behavior that may have evolved due to its adaptive advantages in promoting the survival and reproduction of individuals in a social group. Choice B is more relevant to comparative physiology, while Choices C and D are more focused on neurobiology.

Question 11

Which statement is true with respect to evolution?
A) "If you don't use it, you lose it."
B) Evolutionary success is assessed by the number of one's offspring surviving to reproduce.
C) Evolution benefits the species, in the long run.
D) Evolution benefits the individual.

Accepted Answer

The success of an individual in evolution is ultimately judged by the number of offspring they produce that survive to reproduce themselves. This is known as reproductive fitness. While evolution can benefit a species in certain circumstances, its main driving force is the success of the individual in passing on their genes to the next generation. "If you don't use it, you lose it" is a popular phrase, but it is not necessarily a rule of evolution. Similarly, while evolution may benefit individuals in certain cases, such as through adaptations that allow them to survive better in their environment, the overall goal of evolution is to maximize reproductive success, not individual benefit.

Question 12

A gene is found that controls the age at which a man grows bald, if at all. That gene seldom affects women, even if they have the gene. What kind of gene is this MOST likely to be?
A) An X-linked gene
B) A sex-limited gene
C) A sex-linked dominant gene
D) A sex-linked recessive gene

Accepted Answer

Since the gene affects only men and not women, it is most likely a sex-limited gene. This type of gene is expressed in only one sex and not the other. Additionally, it is not likely to be a sex-linked dominant or recessive gene, as these would affect both sexes. It is also not likely to be an X-linked gene, as women can have the gene without being affected.

Question 13

On a given trait, high heritability suggests that ____.
A) adopted children will closely resemble their biological parents
B) adopted children will closely resemble their adoptive parents
C) identical twins will be less similar to each other than adopted siblings
D) fraternal twins will be more similar to each other than identical twins

Accepted Answer

High heritability suggests that genetic factors play a significant role in the expression of a trait, meaning that biological relatedness (such as between biological parents and their children) will result in greater similarity in the expression of the trait.

Question 14

Evolution improves the fitness of the population, which is evolutionarily defined as ____.
A) the number of copies of one's genes that endure in later generations
B) survival of the individual
C) ability to adapt to a variety of environments
D) overall health and well-being

Accepted Answer

Evolution is driven by the passing on of genes from one generation to the next. Fitness, in an evolutionary context, refers to an individual's ability to pass on their genes. Therefore, the correct answer is A, which describes the number of copies of one's genes that endure in later generations. Survival of the individual, ability to adapt to a variety of environments, and overall health and well-being may all contribute to an individual's fitness, but they are not the primary evolutionary definitions of fitness.

Question 15

An autosomal gene is a gene ____.
A) on the X chromosome
B) on the Y chromosome
C) on any chromosome other than the X or Y chromosome
D) that shows no evidence of crossing over

Accepted Answer

An autosomal gene is a gene that is located on any chromosome other than the sex chromosomes (X and Y). Therefore, choice C is the correct answer. Choice A is incorrect because genes on the X chromosome are sex-linked and not autosomal. Choice B is incorrect because genes on the Y chromosome are also sex-linked and not autosomal. Choice D is incorrect because crossing over can occur between autosomal genes during meiosis.

Question 16

Which statement best explains why males can grow breasts under certain hormonal conditions?
A) Sex-linked genes become activated.
B) The Y chromosome becomes activated.
C) Sex-limited genes become activated.
D) Breast growth is linked to color vision deficiency.

Accepted Answer

Breast growth in males can occur under certain hormonal conditions because of the activation of sex-limited genes. These genes are present in both males and females but are only expressed under certain hormonal conditions. In males, an increase in estrogen levels can lead to the activation of these genes, resulting in breast growth.

Question 17

Changes in single genes are called ____.
A) alterations
B) mutations
C) mendelians
D) enzymes

Accepted Answer

Changes in single genes are called mutations.

Question 18

Individuals afflicted with PKU need to avoid ____.
A) foods high in phenylalanine
B) foods high in vitamin K
C) alcohol
D) sunlight

Accepted Answer

Individuals with PKU have a deficiency in the enzyme needed to break down phenylalanine. As a result, a build-up of this amino acid can cause brain damage and intellectual disability. Therefore, these individuals need to follow a low-phenylalanine diet and avoid foods high in phenylalanine. Foods such as meat, dairy, eggs, nuts, and beans are high in phenylalanine and need to be restricted in their diet.

Question 19

Any estimate of the heritability of a particular trait is specific to ____.
A) a given population
B) the parents
C) the trait
D) the strength of the trait

Accepted Answer

Heritability estimates are calculated for a specific population and may not be generalizable to other populations due to differences in genetic and environmental factors. The heritability of a trait can also vary within different populations.

Question 20

For natural selection to generate evolutionary change in a population ____.
A) there need not be any differences in the traits of individuals in that population
B) the change in gene frequencies must help the species in the long run
C) the differences must have a hereditary basis
D) the change in gene frequencies will probably be harmful to the species

Accepted Answer

Natural selection can only act on traits that have a genetic component and are heritable, meaning that they can be passed down from one generation to the next. Therefore, for natural selection to generate evolutionary change in a population, the differences between individuals must have a hereditary basis. Option A is incorrect because if there are no differences in traits, natural selection cannot act on the population. Option B is incorrect because not all changes in gene frequencies are beneficial for a species in the long run. Option D is also incorrect because natural selection typically favors traits that increase an organism's survival and reproduction, not harm it.

Quiz 4: Genetics, Evolution, Development, and Plasticity

An example of a sex-linked trait is ____.

Suppose that adopted children are more similar to their biological parents than their adoptive parents in their preferences for a flavor of ice cream. Which statement is true in this circumstance?

Sex-limited genes are found on ____.

Which pair of sex chromosomes is found in a normal male mammal?

Breeding some animals selectively because they possess some desirable characteristic is called ____.

Why do children with PKU develop intellectual disabilities?

In general, biologists who speak of sex-linked genes are typically referring to genes on ____.

Which of the following represents Lamarckian evolution?

How is it possible to prevent the intellectual disabilities that are generally associated with PKU?

An evolutionary psychologist would likely be most interested in studying ____.

Which statement is true with respect to evolution?

A gene is found that controls the age at which a man grows bald, if at all. That gene seldom affects women, even if they have the gene. What kind of gene is this MOST likely to be?

On a given trait, high heritability suggests that ____.

Evolution improves the fitness of the population, which is evolutionarily defined as ____.

An autosomal gene is a gene ____.

Which statement best explains why males can grow breasts under certain hormonal conditions?

Changes in single genes are called ____.

Individuals afflicted with PKU need to avoid ____.

Any estimate of the heritability of a particular trait is specific to ____.

For natural selection to generate evolutionary change in a population ____.