Question 1

The relatively high percentage of individuals in West Africa who are heterozygous for the sickle cell trait is an example of _____.

Accepted Answer

The high frequency of sickle cell trait in West Africa is an example of natural selection because the sickle cell allele provides an advantage in resisting malaria, a disease prevalent in the region. Individuals who are heterozygous for the sickle cell allele are less likely to contract malaria, survive to reproductive age, and pass the allele on to their offspring. This results in a higher frequency of the sickle cell allele in the population due to natural selection.

Question 2

The availability of genomic data has allowed scientists to construct more accurate phylogenetic trees than those based on fossil evidence alone.

Accepted Answer

Genomic data provides a wealth of information about the evolutionary relationships between species, and can help to resolve previously uncertain or conflicting relationships inferred from the fossil record. By analyzing shared genomic features or DNA sequences, scientists can construct more robust and detailed phylogenetic trees that reflect the true evolutionary history of life on Earth. However, fossil evidence remains important for understanding the timing and pattern of evolutionary events, as well as for illuminating aspects of extinct species that cannot be inferred from genetic data alone.

Question 3

Hardy and Weinberg showed that the allele frequencies in a non-evolving population change with successive generations.

Accepted Answer

Hardy and Weinberg's model demonstrated that under certain assumptions, the allele frequencies in a non-evolving population would remain constant over successive generations. This is known as Hardy-Weinberg equilibrium. It is only when these assumptions are not met, such as with the presence of genetic drift or natural selection, that allele frequencies will change.

Question 4

Genetic drift is a random process that can change the genetic structure of a population.

Accepted Answer

Genetic drift is a random process that can cause changes in the frequency of alleles (genetic variants) in a population over time. This occurs due to sampling error, or chance events that affect which individuals breed and pass on their genetic information to the next generation. As a result, genetic drift can lead to the loss of certain alleles or the fixation of others within a population, regardless of their selective advantage or disadvantage.

Question 5

The rapid change in G6PD allele frequency and the correlation of this allele with areas of high rates of malaria suggests that ____ explains this change in G6PD allele frequency.

Accepted Answer

The correlation of G6PD allele frequency with areas of high rates of malaria suggests that natural selection, in which the alleles that confer resistance to malaria are selected for, is the likely explanation for the rapid change in allele frequency. This is supported by studies that have shown that individuals carrying G6PD deficiency alleles have a selective advantage in areas with high rates of malaria.

Question 6

The genetic variability of a population is solely dependent on the generation of mutations.

Accepted Answer

While mutations do contribute to genetic variability in a population, there are other factors that also play a role. These include natural selection, genetic drift, gene flow, and recombination. Therefore, genetic variability is not solely dependent on the generation of mutations.

Question 7

The Hardy-Weinberg law can be used to calculate allele and genotype frequencies without genetic testing.

Accepted Answer

The Hardy-Weinberg law is a mathematical equation that can be used to calculate the expected frequencies of alleles and genotypes in a population in the absence of evolutionary forces such as mutation, migration, or natural selection. The equation is based on the assumption that the population is large, randomly mating, and free from any evolutionary change. Therefore, the Hardy-Weinberg law can be used to predict genotype and allele frequencies without genetic testing, but the actual frequencies may differ from the predicted values if any of the assumptions are violated or if there are random fluctuations due to chance events or genetic drift.

Question 8

According to genetic evidence,the migration of H.sapiens out of Africa replaced other human populations,including Neanderthals and H.erectus,leading to their extinction.

Accepted Answer

Genetic evidence shows that H. sapiens migrated out of Africa and replaced other human populations, including Neanderthals and H. erectus, leading to their extinction.

Question 9

Albinism is a recessive trait controlled by a single gene.If the frequency of albinos in a population is 0.25,what is the expected frequency of heterozygotes for this trait?

Accepted Answer

The answer of Albinism is a recessive trait controlled by...

Question 10

Since males have only one X chromosome,the allele frequency of an X-linked trait is equal to the number of males with the recessive phenotype.

Accepted Answer

The allele frequency of an X-linked trait is equal to the number of males with the recessive phenotype because males only have one X chromosome, so if they have the recessive allele, they will express the recessive phenotype.

Question 11

The Hardy-Weinberg law is used to calculate allele and genotype frequencies ____.

Accepted Answer

The Hardy-Weinberg law is specifically used to calculate allele and genotype frequencies when mating is random. It provides a baseline for predicting the genotype frequencies of a population if certain assumptions (such as random mating, large population size, and no selective pressures) are met.

Question 12

Assume the trait for brown eyes is completely dominant to blue eyes and this trait is controlled by a single gene.If 400 people in a population of 10,000 have blue eyes,how many people would be expected to be heterozygous for this trait? (Hint: Use the Hardy-Weinberg formula.)

Accepted Answer

According to the Hardy-Weinberg principle, q^2 represents the frequency of the homozygous recessive genotype (blue eyes). Given q^2 = 400/10,000 = 0.04, q = 0.2. Therefore, p = 1 - q = 0.8. The frequency of heterozygotes (2pq) is 2 * 0.8 * 0.2 = 0.32. Thus, 0.32 * 10,000 = 3,200 people are expected to be heterozygous.

Question 13

There is significantly more genetic variation between human populations than within them.

Accepted Answer

Most genetic studies have shown that the vast majority of genetic variation (about 85-90%) exists within populations, rather than between different populations or ethnic groups.

Question 14

Most geneticists would agree that human races are distinct genetic entities.

Accepted Answer

Most geneticists agree that the concept of race is a social construct and not a biological one. While there may be genetic variations between populations, these variations do not fit neatly into discrete racial categories. Therefore, human races are not considered distinct genetic entities.

Question 15

All evolutionary ancestors of modern humans have been discovered and identified.

Accepted Answer

While many ancestral species have been discovered and identified, there is still ongoing research and discovery in the field of human evolution, and it is possible that new ancestral species will be identified in the future.

Question 16

In a Hardy-Weinberg equilibrium,as the frequencies of homozygous genotypes increase,the frequency of the heterozygous genotype _____.

Accepted Answer

The answer of In a Hardy-Weinberg equilibrium,as the frequencies of...

Question 17

A population that is in genetic equilibrium is said to ____.

Accepted Answer

A population in genetic equilibrium has an allele or alleles that remain constant from generation to generation, which is the definition of genetic equilibrium according to the Hardy-Weinberg law. Option A is not always true in a population in genetic equilibrium, as it depends on the specific allele frequencies. Option B states the opposite of genetic equilibrium, and option C is not necessary to determine genetic equilibrium. Option D is true for populations that undergo genetic drift, but not for those in genetic equilibrium.

Question 18

A loss of 90% of the population in the Pingelap atoll from a typhoon in 1775 resulted in a high percentage of the current population being affected by achromatopsia.As a result,all of these affected individuals _____.

Accepted Answer

The high percentage of achromatopsia in the Pingelap atoll population is due to a genetic bottleneck, where the few survivors of the typhoon, including a carrier of the gene, passed it on to their descendants.

Question 19

A predictable effect of genetic drift in a small population is an increase in _____.

Accepted Answer

Genetic drift results in the loss of genetic variation within a population as alleles are randomly lost over time. In a small population, genetic drift can have a greater impact because there is less genetic diversity to begin with. This can lead to an increase in homozygosity as individuals have a higher chance of inheriting the same allele from both parents, which can have negative consequences such as reduced fitness and increased susceptibility to disease.

Question 20

According to the theory of evolution,those best adapted to the environment will _____.

Accepted Answer

The theory of evolution states that natural selection acts on the variation present in a population, and those individuals who are best adapted to the environment are more likely to survive and reproduce. Thus, the answer is A, as it is the only option that matches this description.

Quiz 19: Population Genetics and Human Evolution