Question 1

When individuals of the same species are reproductively isolated, genetic differences may accumulate in sufficient number so that new species could emerge.Such an event would be an example of:

Accepted Answer

The emergence of new species due to reproductive isolation and accumulation of genetic differences is an example of macroevolution, which refers to the evolutionary changes at or above the species level. Microevolution (choice A) refers to evolutionary changes within a species or population. The founder effect (choice B) refers to the loss of genetic variation that occurs when a small group of individuals colonizes a new habitat. Equilibrium (choice C) refers to the state in which allele frequencies in a population remain constant over time.

Question 2

Over a period of two generations, the frequency of green dung beetles in a population shifts from 75% to 71% while the frequency of brown dung beetles within this population shifts from 25% to 29%.This is an example of:

Accepted Answer

This is an example of microevolution, which refers to small-scale changes in allele frequencies within a population over a short period of time. The shift in frequency of the green and brown dung beetles over two generations is a small-scale change in allele frequency within the population, making it an example of microevolution.

Question 3

Evolution can best be defined as:

Accepted Answer

Evolution is best defined as a change in allele frequencies in a breeding population over time. This change can occur due to natural selection, genetic drift, mutations, gene flow, or a combination of these factors. It does not necessarily result in the appearance of a new species, although speciation can be a result of evolution. Evolution can also occur over short periods of time and is not limited to extremely long periods. Changes in an individual's DNA over their lifetime are not considered evolution, but rather development or aging.

Question 4

The ABO and MN blood-type frequencies of the Dunkers differ significantly from those of current American and German populations due to:

Accepted Answer

Genetic drift is a random process that can cause changes in the frequencies of alleles (such as ABO and MN blood types) in a population over time. The Dunkers are a small, isolated population, so genetic drift could have had a significant impact on their blood type frequencies. Natural selection, gene flow, and mutation are not as likely to explain the differences in blood type frequencies between the Dunkers and other populations.

Question 5

Malaria is caused by:

Accepted Answer

Malaria is caused by the bite of infected female Anopheles mosquitoes that carry the Plasmodium parasite.

Question 6

In certain species of nonhuman primates there are groups where only one dominant female has access to mates.The other females must wait until the opportunity to mate presents itself.This will have direct impacts on "fitness," influencing which of the following?

Accepted Answer

The dominant female's exclusive access to mates means that the other females will have reduced reproductive success, which directly affects their fitness. They may have fewer offspring and therefore pass on fewer of their genes to the next generation. Aggressiveness, strength, and age at death may also be influenced by the female's status within the group, but these factors are not directly related to reproductive success and fitness.

Question 7

Which of the following is NOT a genetic disorder that decreases susceptibility to malaria?

Accepted Answer

Huntington's chorea is not a genetic disorder that decreases susceptibility to malaria. The other three options (G6PD deficiency, sickle-cell anemia, and thalassemia) all confer some level of protection against malaria.

Question 8

Transposable elements are DNA sequences that:

Accepted Answer

Transposable elements are DNA sequences that have the ability to move or "transpose" themselves to different locations within the genome. They can copy themselves into entirely new areas of the chromosomes, and can sometimes cause mutations or alter gene expression. Transposable elements are not necessarily non-coding, nor are they restricted to certain chromosomes. Therefore, options A, B, and C are incorrect.

Question 9

Which of the evolutionary forces is most likely to decrease variation between populations?

Accepted Answer

Gene flow involves the movement of genes from one population to another, which can lead to the mixing of gene pools and decrease the genetic differences between populations. Therefore, gene flow is the evolutionary force most likely to decrease variation between populations. The founder effect, mutation, and natural selection can all increase genetic variation between populations.

Question 10

A point mutation that does NOT result in a change to the amino acid coded for is said to be a _______ mutation.

Accepted Answer

A synonymous mutation is a point mutation that does not change the amino acid encoded for by a codon due to the redundancy of the genetic code. Therefore, it is also known as a silent mutation. The other choices are not relevant to this type of mutation.

Question 11

The physical location of a gene within the genome is called the:

Accepted Answer

The physical location of a gene within the genome is referred to as its locus. Chromosome refers to the structure that carries genes, nucleus refers to the organelle that houses the genetic material, and address is not a term used in genetics.

Question 12

While conducting research with a small population in South America you note that an overwhelming majority of individuals exhibit signs of a specific genetic abnormality.This is most likely the result of:

Accepted Answer

The overwhelming majority of individuals exhibiting signs of a specific genetic abnormality in a small population is most likely due to the founder effect. The founder effect occurs when a small group of individuals establish a new population, and the resulting gene pool may be different from the larger original population from which it was derived. This can lead to a high prevalence of certain genetic traits within the new population.

Question 13

Together, all of the alleles contained within a group of interbreeding individuals are known as a:

Accepted Answer

The term "gene pool" refers to the total collection of genes, including all alleles, that exist within a population of interbreeding individuals. This is the best choice because it specifically refers to the combination of alleles, whereas the other answer choices may not necessarily encompass all of the alleles in the group.

Question 14

Another name for the evolutionary force called gene flow is:

Accepted Answer

Admixture refers to the movement of genes between previously separated populations, which is the same concept as gene flow. The other options are different evolutionary forces. The founder effect refers to a small group of individuals starting a new population with reduced genetic diversity, disruptive selection occurs when extreme phenotypes are favored over intermediate ones, and transposition refers to the movement of genetic material within a genome.

Question 15

Mutations in DNA found in which cells are most likely to have significant evolutionary consequences?

Accepted Answer

Mutations in sex cells have the potential to be passed down to offspring and have significant consequences for future generations, potentially leading to evolutionary changes. Mutations in other cell types may have only local or limited effects on an individual's phenotype and may not be heritable.

Question 16

The southern migration of which African people may have led to a significant increase in the incidence of malaria?

Accepted Answer

Bantu people originated in West Africa and migrated southward around 2000 years ago, settling in regions that are now South Africa, Zimbabwe, and Mozambique. In these areas, the Bantu people encountered the Anopheles mosquito, which carries the parasite responsible for malaria. The Bantu agricultural practices created ideal breeding grounds for mosquitoes, which may have contributed to the significant increase in the incidence of malaria in these regions compared to the areas where the Bantu people did not migrate.

Question 17

The type of selection that favored progressively larger brain size in human evolution is _______ selection.

Accepted Answer

Directional selection favors individuals with a specific trait, leading to a shift in the frequency of that trait over time. In the case of human evolution, there may have been a selective advantage to having a larger brain size, which led to the favoring of individuals with larger brains, and thus a shift in the frequency of larger brain sizes in the population over time.

Question 18

The clinal decrease in type B blood from East Asia to Western Europe is probably the result of:

Accepted Answer

The clinal decrease in type B blood from East Asia to Western Europe is most likely due to gene flow - the movement of individuals and their genes from one population to another. People with type B blood likely migrated and interbred less frequently with populations in Western Europe, resulting in a decrease in the frequency of the B blood type in these regions over time.

Question 19

Australian aborigines are an endogamous society.This means that marriage and reproduction take place within the group, leading to:

Accepted Answer

Endogamy leads to decreased genetic diversity as there is a lack of admixture from outside the group, resulting in a smaller gene pool and an increased likelihood of genetic disorders caused by inbreeding.

Question 20

Hardy-Weinberg equilibrium assumes:

Accepted Answer

Hardy-Weinberg equilibrium assumes that there is no gene flow, mutation, or natural selection occurring in the population. This assumption allows for the mathematical prediction of allele and genotype frequencies in a population over time under certain conditions.

Quiz 4: Genes and Their Evolution: Population Genetics