Question 1

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

Autosomal genes are genes that are located on any chromosome other than the X or Y chromosome. Genes on the X chromosome are known as X-linked genes, while genes on the Y chromosome are known as Y-linked genes. The term "autosomal" simply means that the gene is located on one of the 22 pairs of non-sex chromosomes in humans. The absence or presence of crossing over has no bearing on whether a gene is autosomal or not.

Question 2

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

Sex-limited genes become activated in males under certain hormonal conditions, leading to the growth of breasts. These genes are normally present in both males and females but are expressed only under specific hormonal influences. The Y chromosome and sex-linked genes have no direct connection to breast growth in males, and breast growth is not linked to color vision deficiency.

Question 3

Evolution improves the fitness of the population,which is 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

The fitness of the population is defined as the number of copies of one's genes that endure in later generations. This means that individuals with advantageous traits are more likely to survive and reproduce, passing on their genes to their offspring and increasing their representation in the population over time. Fitness is not necessarily related to an individual's survival, ability to adapt to a variety of environments, or overall health and well-being.

Question 4

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

Evolutionary success is measured by the number of offspring an individual produces that survive to reproduce themselves. Traits that increase an individual's likelihood of producing successful offspring are more likely to be passed on to future generations. This is known as natural selection.

Question 5

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 6

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, which means it is expressed in one sex only. It does not have to be located on a sex chromosome.

Question 7

If a trait has high heritability,____.​
A)hereditary differences will not account for any observed variations in that trait
B)​the environment cannot influence that trait
C)​the environment may possibly influence that trait
D)heredity does not influence that trait

Accepted Answer

High heritability means that genetics play a large role in the variation of a trait, but it does not necessarily mean that environmental factors cannot also influence the trait. Therefore, option C is the most accurate choice.

Question 8

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 genetics play a larger role in determining the trait, so biological relatives (such as biological parents and children) are more likely to share similarities in the trait than non-biological relatives (such as adoptive parents and children). Therefore, adopted children will closely resemble their biological parents.

Question 9

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 popularization of Lamarckian evolution. It suggests that traits acquired during an organism's lifetime can be passed down to the next generation, such as the development of stronger muscles with exercise.

Question 10

​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 (Phenylketonuria) is a genetic disorder caused by a deficiency of the enzyme phenylalanine hydroxylase, which converts phenylalanine into tyrosine. The accumulation of phenylalanine in the blood can lead to intellectual disabilities. However, by following a strict low-phenylalanine diet from birth, intellectual disabilities can be prevented. Therefore, the best choice to prevent intellectual disabilities associated with PKU is through diet.

Question 11

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

In order for natural selection to cause evolutionary change, the traits that are being selected for or against must have a hereditary basis, meaning that they can be passed down from generation to generation through genes. Without this hereditary basis, the changes that are selected for or against would not be passed down and would not result in evolutionary change.

Question 12

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 referring to genes on the sex chromosomes, which in mammals are the X and Y chromosomes. However, most sex-linked traits are controlled by genes on the X chromosome, making C the best choice. Genes on the Y chromosome are less prevalent and are only passed from father to son. Autosomes refer to non-sex chromosomes and would not be considered sex-linked.

Question 13

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

Artificial selection is the process of selectively breeding animals with desirable traits to produce offspring with those same traits. This process is often used in agriculture and animal husbandry to improve the quality of crops or livestock. Evolution refers to the gradual process of change in a population over time, while natural selection is a specific mechanism of evolution where individuals with certain adaptations are more likely to survive and reproduce. Artificial insemination is a technique used to fertilize an egg outside of the body and then implant it in the uterus. It is not directly related to the process of breeding animals selectively for desirable traits.

Question 14

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

Children with PKU cannot properly break down an amino acid called phenylalanine, leading to a buildup of unmetabolized phenylalanine in the blood and brain. This excess phenylalanine interferes with normal brain development and can cause intellectual disabilities.

Question 15

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

Accepted Answer

Color vision deficiency is a sex-linked trait because the gene for color vision is located on the X chromosome. Since males only have one X chromosome, they are more likely to inherit color vision deficiency if the X chromosome they receive from their mother carries the gene for it. Females have two X chromosomes, so even if one X chromosome carries the gene for color vision deficiency, the other X chromosome can compensate and still allow them to see colors normally. Eye color, temperament, and intelligence are not sex-linked traits.

Question 16

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

Accepted Answer

Changes in single genes are called mutations.

Question 17

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

Accepted Answer

Sex-limited genes can be found on any chromosome, but their expression is limited to one sex due to hormonal or other sex-specific factors.

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 are unable to metabolize phenylalanine, an amino acid found in many types of protein. Consuming foods high in phenylalanine (such as meat, dairy, and some grains) can lead to a buildup of this amino acid in the body, causing brain damage, intellectual disability, and other complications. Therefore, individuals with PKU must follow a strict low-phenylalanine diet for life.

Question 19

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

The fact that adopted children are more similar to their biological parents in their preferences for a flavor of ice cream suggests that there is a genetic component to this trait, making the heritability high. It does not necessarily mean that environmental factors do not play a role, but rather that genetics plays a stronger role in shaping this particular preference. Therefore, option D can be ruled out. The statement does not provide any support for flavors of ice cream being naturally selected, so option C can also be ruled out. Option B is incorrect as it suggests that this trait is determined solely by the environment, which is not supported by the given statement.

Question 20

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.

Quiz 4: Genetics, evolution, development, and Plasticity

An autosomal gene is a gene ____.​

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

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

Which statement is TRUE with respect to evolution?​

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

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?​

If a trait has high heritability,____.​

On a given trait,high heritability suggests that ____.​

Which of the following represents Lamarckian evolution?​

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

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

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

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

Why do children with PKU develop intellectual disabilities?​

An example of a sex-linked trait is ____.​

Changes in single genes are called ____.​

Sex-limited genes are found on ____.​

Individuals afflicted with PKU need to avoid ____.​

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?​

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

An autosomal gene is a gene ____.

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

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

Which statement is TRUE with respect to evolution?

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

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?

If a trait has high heritability,____.

On a given trait,high heritability suggests that ____.

Which of the following represents Lamarckian evolution?

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

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

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

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

Why do children with PKU develop intellectual disabilities?

An example of a sex-linked trait is ____.

Changes in single genes are called ____.

Sex-limited genes are found on ____.

Individuals afflicted with PKU need to avoid ____.

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?

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