quiz 13

The Dunkers are a religious group that moved from Germany to Pennsylvania in the mid-1700s. They do not marry with members outside their own immediate community. Today, the Dunkers are genetically unique and differ in gene frequencies, at many loci, from all other populations including their original homeland. Which of the following likely explains the genetic uniqueness of this population? A) sexual selection B) heterozygote advantage and stabilizing selection C) population bottleneck and Hardy-Weinberg equilibrium D) mutation and natural selection E) founder effect and genetic drift

E

In the southeastern United States, there are two species of closely related plants, Yellow Jessamine and Swamp Jessamine. These plants live in the same areas and have the same pollinators. Based upon this information, and the information in this graph, these two species most likely show _____________ isolation. A) temporal B) behavioral C) ecological D) mechanical

A

The gene that codes for the ABO blood group in humans has three alleles. In a population of 1000 people, the frequency of the IA allele is .3, and the frequency of individuals in the population with type O blood is 0.36. What is the frequency of the IB allele in this population? A) 0.1 B) 0.44 C) 0.6 D) 0.9

A

Two populations of birds with somewhat different coloration live on opposite sides of a peninsula. The habitat between the populations is not suitable for these birds. When birds from the two populations are brought together, they produce young whose appearance is intermediate between the two parents. These offspring will breed with each other or with birds from either parent population, and all offspring of these pairings appear intermediate to various degrees.What keeps the two populations separate? A) habitat isolation B) temporal reproductive isolation C) lack of hybrid viability D) behavior isolates reproductive activities

A

Using the Biological Species Concept, two animals are considered members of different species if they ____________________________________. A) cannot mate and produce viable, fertile offspring B) live in different habitats C) look different D) are members of different populations E) are geographically isolated

A

Which of the following is an example of assortative mating? A) A tall female chooses a tall male as a mate. B) Only the dominant male in a species is allowed to mate. C) Young males leave the pack to find a mate in a different pack. D) A male bird builds an elaborate nest to attract potential mates. E) A female peacock chooses a male with the most attractive tail display.

A

The gene that codes for the ABO blood group in humans has three alleles (assume that the frequency of the IA allele = p, IB allele = q, and i = r). An individual who has Type A blood could be represented by which of the following? Select all that apply. A) p2 B) 2 pr C) r2 D) 2 pq

A & B

A new disease wiped out the majority of a population. The only individuals that survived were homozygous for a recessive allele that encodes for a form of an enzyme that is unaffected by the disease toxin. (The converse is true for the dominant allele that encodes for a form of the enzyme that is affected by the toxin.) This is an example of _________________________________. A) assortative mating B) genetic drift C) natural selection D) genetic drift and assortative mating E) the founder effect

C

An adaptation is _______________________________________________. A) a trait that gives rise to a new species B) an individual's attempt to conform to its environment C) a trait that gives an organism a reproductive advantage in the current environment D) the cause of natural selection

C

In historical human populations, children with both high and low birth weight have lower survivorship than children of average birth weight. This is an example of A) heterozygote advantage. B) stabilizing selection. C) diversifying selection. D) directional selection.

B

Which of the following situations can cause genotype frequencies in a population to change? Select all that apply. A) Individuals mate randomly with respect to their genotypes. B) Individuals migrate between populations. C) Mutation introduces new alleles into a population. D) Small groups that are reproductively isolated from the larger population are formed. E) Individuals with all genotypes are able to produce viable, fertile offspring under the environmental conditions that exist.

B & C & D

In a hypothetical situation, a certain species of flea feeds only on pronghorn antelopes. In the western United States, pronghorns and cattle often associate with one another in the same open rangeland. Some of these fleas develop a strong preference for cattle blood and mate only with other fleas that prefer cattle blood. The host mammal can be considered as the fleas' habitat. If this situation persists, and new species evolve, this would be an example of __________________________________. A) allopatric speciation and gametic isolation B) sympatric speciation and temporal isolation C) allopatric speciation and habitat isolation D) sympatric speciation and habitat isolation

D

The recessive genetic condition sickle-cell anemia is more common in parts of the world where malaria is common. This is an example of A) gene flow. B) directional selection. C) stabilzing selection. D) heterozygote advantage.

D

In a population of 1000 people, 640 people have type O blood and the frequency of the IB allele is .1. Using this information, calculate the following allele and genotype frequencies: The frequency of the allele IA allele = The frequency of allele i allele = The frequency of people with type AB blood =

0.1 0.8 0.02

Fill in the blanks with the correct answer. In a population of 1000 people, 40 people have PKU (an autosomal recessive condition). In this population, what is the frequency of the PKU allele? In this population, what is the frequency of the dominant allele? In this population, what is the frequency of carriers?

0.2 0.8 0.32

Fill in the blanks with the correct answer. In a population of 2000 people, 500 people have 5 fingers and 1500 people have polydactyly (an autosomal dominant condition) What is the frequency of the dominant polydactyly allele? How many people are expected to be heterozygous?

0.5 1000

Fill in the blanks with the correct answer. The gene that codes for the ABO blood group in humans has 3 alleles. Assume a population of 1000 people in which the frequency of the IA allele is 0.2 and the frequency of individuals with type O blood is 0.09. What is the frequency of the IB allele in this population? How many people will have type AB blood? How many people will have type A blood?

0.5 200 160

A certain disease in humans follows a simple inheritance pattern through a gene locus with only two alleles: D (the dominant non-disease allele) and d (the recessive disease allele). If the frequency of the recessive allele is 10% in a population of 100,000, how many people would you expect to be healthy carriers of the recessive allele? (Assume Hardy-Weinberg equilibrium.) A) 18,000 B) 36,000 C) 9,000 D) 24,000

A

In humans, a cleft or dimple in the chin is inherited as an autosomal complete dominant trait. In Smallville, USA, 81% of the people have a smooth chin. What is the frequency of the cleft chin allele in that population? A) 10% B) 18% C) 19% D) 90%

A

According to the Hardy-Weinberg theorem, the frequencies of alleles in a population will remain constant if ____________________ is the only process that affects the gene pool. A) genetic drift B) sexual reproduction C) immigration D) sexual selection E) mutation

B

In unicorns, three alleles at a gene determine the condition of the horn. The allele for a twisted horn, HT, and the allele for a long horn, HL, are codominant; both are completely dominant to the hornless allele, h. The frequency of hornless individuals in the population is 16%, and the frequency of the allele for twisted horns is 0.1. What frequency of individuals in the population have horns that are long and twisted? A) 5% B) 10% C) 25% D) 84%

B

Starting from a single wild canine species, humans have developed hundreds of breeds of domestic dogs. Which of the following statements is supported by this observation? A) Natural selection had not occurred very frequently in the wild dog populations. B) There was enough heritable variation in the wild canine species to create a variety of features. C) Heritable variation is low; otherwise the there would be more wild dog species. D) Most of the variation in domestic dog species is a result of variation in nutrition and training.

B

The fossil record for black bears in Europe shows that during warmer periods, the bears decreased in overall size, while during cooler periods they increased in size. This would be an example of ______________________________ selection. A) stabilizing B) directional C) diversifying D) balancing

B

The ability to create unique DNA fingerprints has revolutionized crime solving. On average, about 99.9% of the DNA between two humans is the same and the remaining 0.1% is what makes us unique (unless you have an identical twin!). This may sound like a small difference but it means that there are around three million base pairs that are different between two people. These differences can be compared and used to help distinguish you from someone else. Microsatellites are short sequences (10-60 base pairs long) of repetitive DNA that show greater variation from one person to the next than other parts of the genome. DNA fingerprinting is a technique that simultaneously detects lots of microsatellites in the genome to produce a pattern unique to an individual. This is a DNA fingerprint. The probability of having two people with the same DNA fingerprint that are not identical twins is very small. We can tell from the image above that suspect #1's DNA fingerprint does not match the evidence left at the crime scene. This can be used to exonerate suspect #1. Suspect #2, on the other hand, has a DNA fingerprint that matches the evidence left at the crime scene. But this is not enough evidence for a court of law. To use this DNA fingerprint in a court of law, we need to apply knowledge of population genetics to the fingerprint to determine the probability that two people will have the same fingerprint. To do this we need to know the frequency of each of the microsatellite alleles in the population. We can then use the Hardy-Weinberg equation to calculate the probability that an individual would have this fingerprint. To do this, we need to recognize that if an individual has a single band for a microsatellite sequence - this means the individual is homozygous for that allele (and the frequency of the homozygous genotype is the frequency of the allele squared). If the individual has two bands for a microsatellite sequence - this means the individual is heterozygous (and the frequency of the heterozygous genotype is calculated by using the 2pq part of the equation). To determine the overall probability of a DNA fingerprint such as the one above, the rule of multiplication is used - the individual genotype frequencies for each microsatellite sequence is multiplied together (in this example, the overall probability of the fingerprint = .04 x .01 x .01 x .12 = 0.00000048 (or 1/2,083,333). NOTE: An actual DNA fingerprint used in a criminal court uses 13 different microsatellite sequences and the resulting probabilities of an individual fingerprint are very small. Use this information to answer the following 2 questions. A piece of meat purchased at a fish market was labeled Minke Whale, a species which can be legally harvested. However, other characteristics of the meat suggested that it was from a humpback whale, an endangered species that cannot be harvested. The sample was subjected to DNA fingerprinting for several microsatellite regions - the frequencies for the alleles at these regions for humpback whales are given. What is the overall probability that a whale in this humpback population has this genetic fingerprint? A) 0.0115 B) 0.0369 C) 2.14

B (Yes! The genotype for DNA sequence #1 = 2(.1)(.9) = .18 The genotype for DNA sequence #2 = (.8)2 = .64 The genotype for DNA sequence #3 = 2(.2)(.8) = .32 The genotype for DNA sequence #4 = (1.0)2 = 1.0 The overall probability of this fingerprint = .18 x .64 x .32 x 1.0 = 0.0369)

House finches were found only in western North America until 1939, when a few individuals were released in New York City. These individuals established a breeding population and gradually expanded their range. The western population also expanded its range somewhat eastward, and the two populations have recently come in contact. If the two forms were unable to interbreed when their expanding ranges met, it would be an example of ______________________________________. A) prezygotic isolation B) postzygotic isolation C) allopatric speciation D) sympatric speciation

C

In the Hardy-Weinberg equation, p2 + 2pq + q2 = 1, the term p refers to the: A) frequency of homozygous dominant individuals in the population. B) frequency of the most common allele in the population. C) allele frequency of one allele in the population. D) frequency of heterozygotes in the population.

C

The ability to taste the compound phenylthiocarbamide (PTC) is an autosomal dominant trait. Suppose 36% of the residents of a small town cannot taste PTC. What percentage of the population must be homozygous for the PTC taster allele? A) 48% B) 40% C) 16% D) 32% E) 60%

C

The ________________ is the collection of all alleles in a population. A ______________ is a group of individuals of the same species in a given area who are able to mate and produce fertile offspring. The frequency with which a particular condition or trait occurs in a population is the _____________________ frequency. The frequency with which a particular variant of a gene occurs in a population is called the _______________- frequency.

gene pool population phenotype allele

The evolution of populations due to chance events is ______________ . The transfer of alleles into and out of populations due to the movement of fertile individuals or their gametes is _________________ . __________________ occurs when individuals with inherited traits better suited to their environment survive and produce more offspring than other individuals.

genetic drift gene flow natural selection

Genetic drift is most likely to occur in populations that are ________ . A _____________________ occurs when many members of a population die, leaving only a few survivors. The __________________ may occur when a small group of individuals forms a new settlement. Random changes in allele frequencies are called ________________ .

small population bottleneck founder effect genetic drift

In humans, a recessive allele (d) results in a short middle finger, and the dominant allele (D) of the same gene results in a middle finger of normal length. Suppose that in a population that is in Hardy-Weinberg equilibrium, allele D is present at a frequency of 0.9, and allele d is present at a frequency of 0.1. 1. If the population mates at random, then in the next generation, the frequency of genotype DD will be ______ 2. If the population mates at random, then in the next generation, the frequency of genotype Dd will be ______ 3. If the population mates at random, then in the next generation, the frequency of genotype dd will be ________ 4. If the population continues to mate randomly, then after ten generations, the frequency of allele D will be ______ , and the frequency of allele d will be _______

0.81 0.18 0.01 0.9 0.1

The ability to create unique DNA fingerprints has revolutionized crime solving. On average, about 99.9% of the DNA between two humans is the same and the remaining 0.1% is what makes us unique (unless you have an identical twin!). This may sound like a small difference but it means that there are around three million base pairs that are different between two people. These differences can be compared and used to help distinguish you from someone else. Microsatellites are short sequences (10-60 base pairs long) of repetitive DNA that show greater variation from one person to the next than other parts of the genome. DNA fingerprinting is a technique that simultaneously detects lots of microsatellites in the genome to produce a pattern unique to an individual. This is a DNA fingerprint. The probability of having two people with the same DNA fingerprint that are not identical twins is very small. We can tell from the image above that suspect #1's DNA fingerprint does not match the evidence left at the crime scene. This can be used to exonerate suspect #1. Suspect #2, on the other hand, has a DNA fingerprint that matches the evidence left at the crime scene. But this is not enough evidence for a court of law. To use this DNA fingerprint in a court of law, we need to apply knowledge of population genetics to the fingerprint to determine the probability that two people will have the same fingerprint. To do this we need to know the frequency of each of the microsatellite alleles in the population. We can then use the Hardy-Weinberg equation to calculate the probability that an individual would have this fingerprint. To do this, we need to recognize that if an individual has a single band for a microsatellite sequence - this means the individual is homozygous for that allele (and the frequency of the homozygous genotype is the frequency of the allele squared). If the individual has two bands for a microsatellite sequence - this means the individual is heterozygous (and the frequency of the heterozygous genotype is calculated by using the 2pq part of the equation). To determine the overall probability of a DNA fingerprint such as the one above, the rule of multiplication is used - the individual genotype frequencies for each microsatellite sequence is multiplied together (in this example, the overall probability of the fingerprint = .04 x .01 x .01 x .12 = 0.00000048 (or 1/2,083,333). NOTE: An actual DNA fingerprint used in a criminal court uses 13 different microsatellite sequences and the resulting probabilities of an individual fingerprint are very small. Use this information to answer the following 2 questions. What is the probability of this DNA fingerprint? A) 1.90 B) .0162 C) .045 D) .000182

B

Which of the following is an example of postzygotic reproductive isolation? A) Two species of crickets mating at different times of the year, summer versus fall. B) Two species of toads whose offspring die before reaching sexual maturity. C) Two species of plants where the pollen from one species cannot break through the ovule of the other. D) Two species of lizard that live in different parts of the same tree.

B

Which of the following is an example of the founder effect? A) A tornado destroys all but 15 individuals in a toad population. B) A group of 15 male and female birds from one species are stranded on an island. C) Only ampicillin-resistant bacteria survive in an ampicillin-rich medium. D) A group composed of 12 male birds from one species is released 5 miles from their home range.

B

Which of these is an example of temporal isolation? A) One is a type of primate, the other is a type of marsupial. B) One species is nocturnal, and the other species is not. C) One species performs a specific courtship dance. the other species does not. D) One species is found only in New York, the other only in London. E) The average weight of the individuals in one species is 45 kg; in the other species the average is 290 kg.

B

Which statement best represents the meaning of the term evolution: A) Changes in species toward greater complexity over time. B) Changes in gene frequencies in a population over time. C) The strongest individuals survive and produce the most offspring. D) Changes in an individual over time in response to natural selection.

B

Which of the following MUST exist in a population before natural selection can act upon that population? Select all that apply. A) sexual reproduction B) variation among individuals in reproductive success C) genetic variation among individuals D) large population size

B & C

Claytonia virginica is a woodland spring herb with flowers that vary from white to pink. Slugs prefer to eat pink-flowering over white-flowering plants (due to chemical differences between the two), and plants experiencing severe herbivory are more likely to die. The bees that pollinate this plant prefer also prefer pink over white flowers, so that Claytonia with pink flowers have greater relative fruit set (reproductive success) than Claytonia with white flowers. A researcher observes that the percentage of different flower colors remains stable in the study population from year to year. If the researcher removes all slugs from the study population, what would you expect to happen to the distribution of flower colors in the population over time? A) The distribution of flower colors should not change. B) The percentage of white flowers should increase over time. C) The percentage of pink flowers should increase over time. D) The distribution of flower colors should randomly fluctuate over time.

C

If biological species are defined in terms of reproductive compatibility, the formation of a new species hinges on __________________________________. A) gene pool expansion B) gene flow C) hybrid formation D) reproductive isolation

D

If four percent of a population shows a recessive trait, what will be the frequency of carriers in the following generation? A) 4% B) 8% C) 16% D) 32% E) 64%

D