Question 1

A population carries two alleles for a trait in which T is dominant and t is recessive. In the Hardy-Weinberg equation, p2 represents:

Accepted Answer

p2 represents the frequency of the homozygous dominant genotype in the population. By definition, p2 refers to the fraction of individuals in a population that have two copies of the dominant allele (T), which is the homozygous dominant genotype. Therefore, the correct answer is A, the proportion of homozygous dominant individuals.

Question 2

The gene pool for a particular gene is made up of:

Accepted Answer

A

Question 3

According to the Hardy-Weinberg principle, if 75% of the alleles in the gene pool are A1 and 25% are A2, what is the proportion of individuals with genotype A1A2 in this population?

Accepted Answer

The proportion of individuals with genotype A1A2 is calculated using the formula 2pq, where p is the frequency of allele A1 (0.75) and q is the frequency of allele A2 (0.25). So, 2 * 0.75 * 0.25 = 0.375.

Question 4

An allele frequency is:

Accepted Answer

An allele frequency is the proportion of a specific allele in a population's gene pool, which is often expressed as a percentage. For example, if there are 100 individuals in a population, and 60 of them have the dominant allele A and 40 have the recessive allele a, then the frequency of the A allele would be 0.6 or 60%.

Question 5

A population carries two alleles for a trait in which T is dominant and t is recessive. In the Hardy-Weinberg equation, 2pq represents:

Accepted Answer

2pq represents the proportion of heterozygous individuals in the population according to the Hardy-Weinberg equation.

Question 6

Which of the following is MOST likely to experience genetic drift?

Accepted Answer

Genetic drift is a random fluctuation in allele frequency that occurs in small populations. A population of endangered birds that includes only five individuals is most likely to experience genetic drift because it is a very small population size.

Question 7

Evolution can be defined as:

Accepted Answer

Evolution is defined as a change in the genetic makeup of a population over time, which can lead to the development of new species.

Question 8

Inbreeding is defined as:

Accepted Answer

Inbreeding is the process of sexual reproduction between closely related individuals, such as siblings or cousins. This can lead to an increased frequency of homozygous individuals, which can increase the expression of deleterious recessive traits and decrease genetic variation in the population.

Question 9

Imagine that one of the original four mice that escape from a research lab is blind due to a genetic defect. If the mice breed and most of the mice born in subsequent generations are blind from birth, this is most likely a case of:

Accepted Answer

The blind mice are likely to pass on the genetic defect to their offspring, resulting in a high proportion of blind mice in subsequent generations. This is an example of the founder effect, where a small group of individuals (in this case, the four original mice) start a new population that is genetically distinct from the original population. As a result, the frequency of certain alleles (like the genetic defect that causes blindness) may be different in the new population, and over time, those alleles may become more common due to genetic drift.

Question 10

A population carries two alleles for a trait in which T is dominant and t is recessive. In the Hardy-Weinberg equation, q2 represents:

Accepted Answer

According to the Hardy-Weinberg equation, q2 represents the proportion of homozygous recessive individuals. In this case, q represents the frequency of the recessive allele (t), and q2 represents the frequency of individuals who are homozygous for that allele (tt).

Question 11

In the context of evolution, equilibrium means:

Accepted Answer

In the context of evolution, equilibrium refers to the state in which there is no change in the frequencies of alleles in a population over time. This means that the population is not evolving, and the genetic makeup of the population remains stable. Therefore, choice A is the best answer.

Question 12

Which of the following can evolve?

Accepted Answer

The answer of Which of the following can evolve?
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Question 13

Populations of organisms are constantly evolving, which means they are always:

Accepted Answer

Evolution by natural selection results in changes in populations of organisms over time. These changes can be driven by a variety of factors such as mutations, genetic drift, gene flow, and natural selection. Therefore, populations are always changing rather than being static or improving towards some ideal form.

Question 14

In an equilibrium population:

Accepted Answer

An equilibrium population is defined as a population where the allele frequencies do not change. This means that the population is not evolving, and therefore natural selection, mutation rates, and rates of gene flow are not affecting the allele frequencies. However, this does not mean that the population size cannot change, as it can still fluctuate due to other factors such as birth and death rates, migration, and environmental conditions.

Question 15

Within a large population, if no mutations occur, no migration occurs, all matings are random, and each individual has an equal chance of reproducing, which of the following will probably happen?

Accepted Answer

With no mutations or migration and random mating, there will be no input of new genetic variation into the population, and no selective pressures acting on the existing variation. Therefore, the allele frequencies will remain unchanged over time, and no evolution will occur. This is known as genetic equilibrium or Hardy-Weinberg equilibrium. If the population size remains constant, there will also be no drift, bottleneck or fixation events. However, any violation of these assumptions (such as selection, migration, mutation, non-random mating, genetic drift, or changes in population size) can disrupt the equilibrium and lead to evolutionary changes.

Question 16

In a very small population of birds, assume 5 out of 20 alleles are the type that code for blue feathers. What is the allele frequency of the "blue feather allele" in this population?

Accepted Answer

The allele frequency is calculated by dividing the number of specific alleles by the total number of alleles. Here, 5 out of 20 alleles are for blue feathers, so the frequency is 5/20 = 0.25.

Question 17

From an evolutionary point of view, what important process occurs when a young male baboon leaves the troop that he was born in to join another troop?

Accepted Answer

When a young male baboon leaves the troop that he was born in to join another troop, he brings with him new genetic material through gene flow. This process is important for maintaining genetic diversity within a population and can lead to evolution over time.

Question 18

The interaction of genes and environment produces a specific:

Accepted Answer

While genes provide the blueprint for an organism, the environment in which an organism develops and lives can have a significant impact on the expression of genes. The interaction of genes and environment results in a specific phenotype, or set of observable traits and characteristics. Therefore, the best choice is D - phenotype.

Question 19

A population is defined as:

Accepted Answer

A population is a group of individuals of the same species that are located in a specific geographic region. Option A is incorrect because it includes individuals located throughout the world. Option C is incorrect because it includes individuals of all species. Option D is incorrect because it specifies a given country, which may not correspond to the range of the species. Option E is incorrect because it refers to individuals that have the same genetic makeup, which is not necessarily true for all individuals in a population.

Question 20

Which of the following can cause evolutionary change in a small population?

Accepted Answer

Genetic drift is the random change in allele frequencies that occurs in small populations.

Quiz 15: How Populations Evolve