Deck 19: Population Genetics and Human Evolution

Question 1

Which of the following is an incorrect assumption of the Hardy-Weinberg law?

A) The population is very small.
B) No selection.
C) Random mating.
D) No mutations.
E) No migration.

Answer 1

A

Question 2

Genomic studies of Neanderthals, modern humans, and chimpanzees confirms which of the following?

A) Humans evolved from Neanderthals.
B) Humans and Neanderthals interbred.
C) Humans and Neanderthals are not closely related.
D) Humans and Neanderthals both evolved from chimpanzees.
E) More than one of these is confirmed by the genomic comparisons.

Answer 2

E

Question 3

Which of the following species of Homo did NOT live contemporaneously with H. sapiens?

A) H. neanderthalensis
B) H. floresiensis
C) H. erectus
D) H. habilis
E) All of these species of Homo did live contemporaneously with H. sapiens.

Answer 3

D

Question 4

If natural selection is real, why do lethal recessive disorders still exist in populations?

A) Recessive disorders most frequently do not manifest until later in life, after the individual has reproduced.
B) Recessive alleles remain hidden in carriers who are not affected by the disorder.
C) There may be an advantage to individuals who are heterozygous.
D) Recessive disorders most frequently do not manifest until later in life, after the individual has reproduced; and recessive alleles remain hidden in carriers who are not affected by the disorder.
E) Recessive alleles remain hidden in carriers who are not affected by the disorder; and there may be an advantage to individuals who are heterozygous.

Question 5

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? (Hint: use the Hardy-Weinberg formula)

A) 0.25
B) 0.50
C) 0.75
D) 0.90
E) It is not possible to determine with the information provided.

Question 6

The trend toward increased mobility of the world populations will probably lead to

A) increased allele frequency differences among populations.
B) decreased allele frequency differences among populations.
C) a decrease in mutation rate.
D) no change in allele frequency differences among populations because of selection.
E) none of these.

Question 7

It has been suggested that the allele for cystic fibrosis may confer some protection against

A) tuberculosis.
B) malaria.
C) bacterial diarrhea.
D) typhoid fever.
E) bacterial diarrhea and typhoid fever only.

Question 8

Because of a population crash in 1775, the Pingalese have the highest incidence of ____________ in the world.

A) hemophilia
B) cystic fibrosis
C) achromatopsia
D) amytrophic lateral sclerosis
E) Huntington disease

Question 9

To be effective as a force changing genetic diversity, drift requires

A) a long period of time.
B) selection.
C) small, isolated populations.
D) large-scale migrations.
E) geographic stability.

Question 10

The phenotypic differences between chimps and humans is best explained by ______________.

A) the high variation in number of different genes between the two species
B) the high number of inversion sequences
C) epistatic changes to genes
D) patterns of gene expression and regulation
E) the large amount of "junk DNA" found in chimpanzee genomes

Question 11

Godfrey Hardy and Wilhelm Weinberg mathematically proved that as time goes by in a non-evolving population

A) the frequency of homozygotes will increase.
B) heterozygotes will increase.
C) dominant genes will increase to a 3:1 ratio.
D) the proportion of all genotypes will remain constant.
E) recessive genes will gradually increase.

Question 12

Of the following hominin species, which appears first in the fossil record?

A) Australopithecus afarensis
B) Australopithecus africanus
C) Australopithecus anamensis
D) Australopithecus garhi
E) Paranthropus aethiopicus

Question 13

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

A) natural selection
B) genetic drift
C) spontaneous mutational spread
D) heterozygote disadvantage
E) more than one of these

Question 14

According to Darwin, fitness is a measure of

A) survival.
B) differential reproduction.
C) survival and differential reproduction.
D) migration ability.
E) genetic mutation rates.

Question 15

Mutation as a force in genetic diversity serves to

A) increase genetic diversity.
B) rapidly change allele frequencies.
C) maintain a genetic equilibrium.
D) work against selection.
E) do none of these.

Question 16

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

A) mutations.
B) dominant alleles.
C) recessive alleles.
D) genetic variation.
E) homozygosity.

Question 17

Genetic analysis indicates that North America was originally populated by three or four different waves of immigrants who

A) all came from Asia.
B) came from Asia and Europe.
C) came from Asia and Africa.
D) all came from Africa.
E) came from Africa and Europe.

Question 18

Assume 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)

A) 800
B) 540
C) 320
D) 960
E) It is not possible to determine with the information provided.

Question 19

The taxonomic category that includes species of apes, humans, and their ancestors is the ___________.

A) hominids
B) hominins
C) hominoids
D) hominanies
E) homanities

Question 20

Why is it easy to measure allele frequencies in a codominant allele system?

A) Such systems are rare.
B) Phenotypes are equivalent to genotypes.
C) Most alleles are present in homozygous condition.
D) They are present in a 1:2:1 ratio in all populations.
E) None of these is true.

Question 21

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

Question 22

To measure gene flow between populations, one must use genes for which the populations' frequencies are significantly different.

Question 23

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

Question 24

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

Question 25

Changes in the allele frequencies in a large population are mainly due to migration.

Question 26

Allele frequencies can be used to determine phenotype frequencies.

Question 27

When applying the Hardy-Weinberg law to a gene with dominant and recessive alleles, calculation of the allele frequencies always begins by writing the frequency of the ____________________ phenotype, then taking the ____________________ of that to obtain the frequency of the recessive allele.

Question 28

Random mating is more effective in changing allele frequencies of a population than is mutation.

Question 29

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

Question 30

For codominant alleles, the frequency of the different phenotypes cannot be used to determine the allele frequencies.

Question 31

Which of the following populations have a small percentage of Denisovan genes?

A) Melanesians
B) Maori
C) Aztec
D) European
E) Australian aborigines

Question 32

Only ____________________ and randomly breeding populations will fit the Hardy-Weinberg expectations.

Question 33

The sum total of all the genes in an interbreeding population is the gene pool.

Question 34

The ____________________ provides a means of measuring allele frequencies in the population.

Question 35

If a population is in genetic equilibrium, it is in equilibrium for alleles of all genes.

Question 36

Fitter genotypes are defined as those that confer the ability to survive and reproduce at a higher frequency.

Question 37

In areas where malaria is endemic, sickle cell disease heterozygote carriers are less fit than individuals homozygous for the normal allele.

Question 38

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

Question 39

The Hardy-Weinberg law is based on the assumptions that no genotype is superior to any other and that ____________________ and ____________________ are absent from a population.

Question 40

The ultimate source of new alleles and genetic variability is ____________________.

Question 41

Hemophilia is an X-linked trait caused by the allele h. About 1 in 10,000 males (.0001) has hemophilia. The frequency of h, therefore, is ____________________.

Question 42

To a geneticist, races are populations of the same species where allele frequences differ by _________ percent to ___________ percent.

Question 43

The idea that H. erectus populations in Africa, the Middle East, and Asia all collectively interbred and evolved into H. sapiens is called the ____________________ hypothesis.

Question 44

The sickle cell allele is spread through the population in West Africa and maintained at a high frequency due to ____________________ advantage.

Question 45

Heterozygotes for the Tay-Sachs disease allele appear to have greater than normal resistance to ____________________.

Question 46

The first hominin known to use sophisticated tools and fire was _______________.

Question 47

The out-of-Africa model states that Homo sapiens arose from a single population in Africa about ____________________ years ago.

Question 48

The measure of differential survival and reproductive success is termed ____________________.

Question 49

Because of the ____________________ effect, traits carried by early settlers are found in a large fraction of the population.

Question 50

Outline the reasons why a dominant mutation will not spread through a population until it is present at a frequency of 75 percent.

Question 51

To trace the migration of human populations across the globe, geneticists and anthropologists often make use of genetic markers. What criteria should be used in selecting such markers? What are some of the problems that might be encountered in such genetic studies?

Question 52

Comparative genome studies show that humans and chimpanzees shared a common ancestor approximately ____________ million years ago.

Question 53

In a large population on a Pacific island, a few individuals had a mutation that caused them to have different colored eyes. After a hurricane, the population was reduced to only a few individuals, but some of those individuals had the rare eye color mutation. Now, after many generations, almost half of the population on this island has different colored eyes. This is an example of _____________.

Question 54

Gene frequencies often differ from population to population. What factors might hold gene frequencies at different levels in adjacent populations?

Question 55

As a measure to remove deleterious genes from the gene pool, it has often been suggested that individuals affected with certain genetic disorders should be sterilized to prevent transmitting the gene to future generations. Would such measures be effective? Why or why not?

Question 56

The taxonomic category that includes all bipedal primates is the ______________.

Question 57

If .04 percent (.0004) of the people in a population have sickle cell anemia, the percent of heterozygotes in the population must be ____________________.

Question 58

In a hypothetical population of 1,000 people, there is a hypothetical trait called pink toe. People who are homozygous dominant have red toes; those who are homozygous recessive have white toes; those who are heterozygous have pink toes. If 400 people have red toes, the number of people with pink toes is ______________.

Question 59

Genetically, humans and chimpanzees are _________ percent the same.

Question 60

A deficiency in the enzyme G6PD confers resistance to the disease _______________.

Question 61

One would think that deleterious genes would be eliminated by natural selection, yet we have two human genetic disorders with a high carrier frequency, sickle-cell anemia and cystic fibrosis. Why has this high frequency for these conditions remained in the population?

Question 62

Describe five things that can cause a change in the allele frequencies in a population.

Question 63

How can genetics be used as a tool to reconstruct the history of the human species?

Question 64

Compare and contrast the out-of-Africa model and multiregional theories of the origin of modern man. Which theory is supported by the preponderance of genetic evidence? What type of evidence supports the other theory?

Question 65

Why is it that mutation, acting alone, has little effect on evolution? What other factors will magnify the effect?

Question 66

Outline the assumptions made in establishing the Hardy-Weinberg law.

Question 67

What is the effect of genetic drift on evolution? How does the founder effect work to cause change in allele frequency?

Question 68

In the U.S., many states passed laws against miscegenation, or marriage between individuals of different races. What genetically based arguments would you use in support or opposition to such laws?

Question 69

In studying evolutionary relationships using molecular techniques, which is more informative: allele frequencies for proteins such as blood groups, or DNA sequence analysis? Why?

Question 70

Selection has obviously affected the frequency of alleles for sickle cell hemoglobin and perhaps the frequencies for cystic fibrosis. What factors might be responsible for inter-population differences in other alleles such as the ABO system?

Question 71

In discussing customs and laws affecting marriages between relatives, it is often said that consanguineous matings lead to an increase in the frequency of deleterious alleles in the population. Is this true? Why or why not?