Deck 20: Variation and Selection in Populations

Question 1

What evidence supports the hypothesis that humans originated in Africa?

A)H.spaiens genomes contain some Neaderthal DNA sequences.
B)A Y chromosomal mutation is common in 1 in 1,000 males in Asia.
C)Mt sequence variation is least in African populations.
D)Mt sequence variation is highest in African populations.

Answer 1

Mt sequence variation is highest in African populations.

Question 2

The Hardy-Weinberg equation is best at predicting short term genotypic frequencies since

A)the equation does not take into consdieration epistatic effects.
B)it is based on inhertiance based on Mendel's second law.
C)the equation is based on Mendelian principles of single gene inheritance.
D)over the long term some of the assumptions of the equation will not be true.

Answer 2

over the long term some of the assumptions of the equation will not be true.

Question 3

Many human recessive genetic diseases are maintained despite continuing selection against them because

A)heterozygotes have a higher fitness than either homozygote.
B)the recessive alleles mutate to dominant type.
C)there is no inheritance for the recessive allele.
D)the dominant allele frequency remains the same over generations.

Answer 3

heterozygotes have a higher fitness than either homozygote.

Question 4

The proportion of individuals in a population that are of a particular phenotype is the

A)phenotype frequency.
B)genotype frequency.
C)allele frequency.
D)None of the choices is correct.

Question 5

Why do the alleles that confer insecticide resistance in mosquitoes become less frequent in the population when insecticide application is disconintued?

A)The mosquiotes experienced a bottle neck effect
B)The alleles were linked to a color variation that allowed for the mosquitoes that were resistant to have a higher rate of predation.
C)The population experienced genetic drift
D)The alleles for resistance had a negative fitness cost.

Question 6

The proportion of individuals in a population that are of a particular genotype is the

A)phenotype frequency.
B)genotype frequency.
C)allele frequency.
D)None of the choices is correct.

Question 7

Biological ancestry describes the

A)the possibility of inheriting mitochondria from the mother.
B)memebers of different generations interact.
C)shared genes but not parentage.
D)parentage and not shared genes.

Question 8

The frequency of the Hemoglobin A allele is 0.9.The heterozygote with the recessive allele, s, shows resistance to the malarial parasite.What is the frequency of the heterozygote for the pair As?

A)0.81
B)0.1
C)0.01
D)0.18
E)0.09

Question 9

The sum total of all alleles carried in all members of a population is called its

A)gene pool.
B)genome.
C)ploidy.
D)polygenic sum.
E)polymorphism.

Question 10

The loss of allelic variation due to an event that decreases the size of the entire population is called

A)gene flow.
B)genetic drift.
C)founder effect.
D)population bottleneck.
E)selection.

Question 11

Which of the following is not one of the assumptions of the Hardy-Weinberg law?

A)The population is very large.
B)Non-random mating occurs within the population.
C)Mutations in the alleles do not occur.
D)No migration occurs into or out of the population.
E)The ability of all genotypes for survival and reproduction is the same.

Question 12

New mutations that arise within a population are typically lost primarily do to

A)most mutations occur in individuals that are exposed to environmental mutagens and they therefore experience mutations in many different genes which means that they do not survive to reproduce.
B)most mutations are lethal.
C)new mutations all result in a lower reproductive fitness.
D)populations are of a finite size and new mutations are frequently lost by genetic drift.

Question 13

In humans, brachydactyly is a dominant condition; 6,400 people in a population of 10,000 show the disease (1,600 are BB, 4,800 are Bb) and 3,600 are normal phenotypes (bb).The frequency of the b allele is

A)0.6.
B)0.4.
C)0.36.
D)0.48.
E)0.16.

Question 14

How has DNA sequencing clarified the relationship between modern humans and other lineages?

A)It has demonstrated that humans are the direct descendants of a linage that was started by Denisovian and Neadtheral interbreeding.
B)It has demonstrated that modern humans did not interbreed extensively with other lineages.
C)It has demonstrated that modern humans interbred extensively with other lineages.
D)It has demonstrated that modern humans are the direct descendants of Neaderthals.

Question 15

In forensics analysis 13 loci are types and the probability of finding an individual in a population with that specific combination of SSR types calculated based on

A)determining whihc allele is the rarest for each loci and then determining of the individual sample contains those loci.
B)calculating the total number of alleles for all loci ion the population.
C)the Hardy-Weinberg Law
D)multiplying the total number of alleles in the population by 2.