Biology Chapter 5

Consider the following family pedigree, which traces the inheritance of a recessive disorder. What is the probability of the individuals in the third generation (III) expressing the disorder?

0%

In a cross involving two autosomal traits on different chromosomes in which the parents are purebred for the opposite forms of both traits, how many of the offspring would be expected to be homozygous recessive for both traits?

1 out of 16

Assuming complete dominance, what is the expected ratio of genotypes of the offspring following the cross of two heterozygotes?

1:2:1

In a cross of two individuals that are both BbDd, how many offspring would be deaf with black coats?

3

Assuming complete dominance, what is the expected ratio of phenotypes of the offspring following the cross of two heterozygotes?

3:1

A woman with blood type B and a man with blood type A could have children with which of the following phenotypes?

A, B, AB, or O

A homozygous milk chocolate Easter bunny is crossed with a homozygous dark chocolate Easter bunny. Assuming dark chocolate is dominant over milk chocolate and the traits segregate according to Mendelian genetics, which traits will be observable in the offspring?

All dark

What is a carrier?

An individual that is healthy but carries one disease-causing recessive allele Submit

Cauliflower, broccoli, Brussels sprouts, cabbage, and kohlrabi are all the same species of plant. What is responsible for the differences in these vegetables?

Artificial selection

The following F1 cross is made: BBGg × Bbgg. Which is not a possible outcome in the F2 generation?

BbGG

In dogs, coat color (B or b) and hearing (D or d) are both genetically determined. If a dog is genotype BBDd, what gametes could it make?

Bd, BD

A __ symbol is used to represent females in a pedigree.

Circle

What do we call a genetic cross that follows two separate characters, such as pea seed color and pea seed shape?

Dihybrid cross

A breeder wants to set up a program to produce zebrafish with long fins. Having long fins is a dominant trait compared to the short-finned wild type. Before she can market her zebrafish, she needs to perform a test cross on the long-finned fish she plans to use as a breeder. How can she tell whether her fish are homozygous or heterozygous for the long-finned trait?

Do several test crosses between the long-finned fish and the short-finned fish; if the offspring are always long finned, the long-finned parent is probably homozygous.

Imagine that five hypothetical genes are arranged on a chromosome in the following order: G--H--I--J--K. Which two genes are most likely to have a crossover occur between them?

G and K

What contribution did Charles Lyell make?

He provided the first evidence that the Earth is much older than was previously thought.

How might global warming result in most grizzly bears having fur that is less dense in the future?

In any population of bears, some individuals have thick fur, some have thin fur, and some are in between. As temperatures increase with the passage of time, the survival of bears with thin fur will increase, and the number of bears in the population with thick fur will decrease.

What is Mendel's law of independent assortment?

Independent assortment means that each pair of alleles segregates independently of the other pairs of alleles. Submit

When I say a flower is "purple," what have I described?

Its phenotype

Before Darwin published his work, Lamarck and others had suggested mechanisms for evolution. By what means did Darwin propose species evolved over time?

Natural Selection

Which two observations led Darwin to conclude that there is competition for survival?

Overproduction of organisms and limited food resources

Assuming incomplete dominance, if a homozygous red-flowered plant is crossed with a homozygous white-flowered plant, what will be the color of the offspring?

Pink

Which of the following processes generates a continuum (spectrum) of varying phenotypes?

Polygenic inheritance

Fur color in rabbits is controlled by multiple alleles. What does this mean?

Rabbit fur color is controlled by a single gene, but there are multiple versions of that gene.

The inheritance pattern for red-green color blindness is different for males compared to females. Red-green color blindness is much more common in males than in females. What does this suggest about the gene for red-green color blindness?

The gene for this trait is located on the X sex chromosome.

Define Mendel's law of independent assortment.

The inheritance of one character has no effect on the inheritance of another character.

Which of the following statements describes Mendel's law of independent assortment?

The inheritance of one characteristic does not affect the inheritance of another characteristic.

What prompted Darwin to publish his book decades after he began writing it?

Wallace, a colleague, was about to publish a similar manuscript.

An individual can be homozygous for a trait, which means ________.

both of their alleles carry the same information

Sickle-cell disease is caused by a recessive form of hemoglobin. Two parents that do NOT have the disease give birth to a child that does. What are the genotypes of the mother and father for the hemoglobin gene?

both parents are heterozygous

Two alleles of the same gene ________.

can be the same or can be different

An individual that expresses a trait is shown as a __ symbol.

colored

Comparing the body structures of organisms to find evidence of a shared evolutionary history is called ________

comparative anatomy

Imagine that eye color in cats is controlled by a single gene and that there are two alleles: black eyes and orange eyes. All the offspring of a cross between a black-eyed cat and an orange-eyed cat have black eyes. This means that the allele for black eyes is __________ the allele for orange eyes.

dominant to

The modern evolutionary synthesis of the 1930s and 1940s melded together Darwin's findings with ________.

genetics

A testcross is performed to determine if a specific individual is a carrier. The results generate a 50/50 ratio of phenotypes. The test subject is therefore ________.

heterozygous

Natural selection acts on ________, and ________ evolve.

individuals; populations

Individuals with variations that make them best suited to their environment are, on average, more likely to ________.

survive and reproduce

The recessive trait is expressed in an individual when ________.

the individual has two recessive alleles

Individuals in the oldest generation are shown in the __ of a pedigree.

top row

If genes are described as "sex linked," then they are ________.

typically on the X chromosome