Bio 1200; Chapter 20 Genes within Populations
If the frequency of allele b in a population is equal to 0.7 then the frequency with which a gamete will carry allele b, is equal to ___________ if the population is in Hardy-Weinberg equilibrium.
0.7
You are examining allele frequencies of a gene in a population of frogs. This gene has two alleles, T and t. If the frequency of the dominant allele (T) is 0.25, then the frequency of the recessive allele (t) is _________.
0.75
Describe how a mutation can cause a phenotypic change by ordering the casual relationship between genes and phenotypic traits, beginning with the occurrence of a mutation at the top.
1. Mutation causes a change in the nucleotide sequence of DNA 2. The altered nucleotide sequence encodes a different amino acid in the structure of a protein 3. The altered amino acids causes a change in the function of a protein 4. The new function of the protein results in a different phenotypic trait of an individual
Place predators and guppy features in the appropriate category: 1. Steams/Pools just above waterfalls 2. Steams/Pools just below waterfalls A) Main Predator is kill-fish B) Guppies are large and colorful C) Main Predator is the pike child D) Guppies have drab coloration and are small
1.Steams/Pools just above waterfalls A) Main predator is kill-fish B) Guppies are large and colorful 2.Steams/Pools just below waterfalls C) Main predator is the pike child D) Guppies have drab coloration and are small
Select all of the following that could cause evolutionary change by natural selection. A) A moth that has a gene for cryptic coloration B) A plant with an enzyme that makes it disease-resistant C) A horse that develops larger muscles through training D) A human who experiences a sunburn
A) A moth that has a gene for cryptic coloration B) A plant with an enzyme that makes it disease-resistant
The number of copies of an allele in a population divided by the total number of all alleles for that gene in a population is the A) Allele frequency B) Genotype frequency C) Mean fitness of the population D) Frequency of Heterozygosity
A) Allele frequency
The green coloration of the caterpillar larvae of the butterfly Colias eurytheme is an example of which of the following? A) Camoflauge B) Avoidance C) Mimicry
A) Camoflauge
In both oscillating section and frequency dependent election, the precise form of selection A) Changes over time B) Remains unchanged over time C) Depends on the frequency of a genotype in a population
A) Changes over time
Select all the effects of the pesticide resistance alleles in housefly genes A) Enhance function of detoxifying enzymes B) Decrease the uptake of insecticides C) Process insecticide molecules and display them on cell surface D) Decrease the binding ability of insecticides
A) Enhance function of detoxifying enzymes B) Decrease the uptake of insecticides D) Decrease the binding ability of insecticides
Sexual selection influences A) Fitness B) Mate Choice C) Mating Success D) Individual genotypes
A) Fitness B) Mate Choice C) Mating Success
Evolutionary change within population can result from which of the following? A) Migration B) Experience C) Mutation D) Natural Selection
A) Migration C) Mutation D) Natural Selection
Fitness is a measure of : A) Survival B) Mating Success C) Physical Strength D) Number of offspring produced per mating
A) Survival B) Mating Success D) Number of offspring produced per mating
Select all of the following that can result from a population bottleneck. A) Surviving members of the population may have different allele frequencies than the original population B) New mutations have been introduced into the population, which may result in changes in allele frequencies C) The genetic diversity of the surviving population is usually lower than the genetic diversity of the original population
A) Surviving members of the population may have different allele frequencies than the original population C) The genetic diversity of the surviving population is usually lower than the genetic diversity of the original population
Select all of the following that can result from assortative mating: A) The proportion of heterozygotes in the population decreases B) The proportion of heterozygotes in the population increases C) The proportion of homozygotes in the population decreases D) The proportion of homozygotes in the population increases
A) The proportion of heterozygotes in the population decreases D) The proportion of homozygotes in the population increases
What is fitness? A) The relative likelihood that a genotype will contribute to the gene pool of the next generation. B) The ability to exercise for a prolonged period of time C) The ability to maintain an internal environment that is suitable for cellular functions. D)The relative likelihood that a genotype will survive.
A) The relative likelihood that a genotype will contribute to the gene pool of the next generation
Select all of the following that are true about SNPs. A) They are single-base differences B) They occur less than 1% in the population C) They are short insertions D) Several million have been noted in the human genome
A) They are single-base differences D) Several million have been noted in the human genome
In a laboratory experiment, researchers placed guppies in three different types of pools: no predation, low predation, and high predation. Researchers hypothesized that predation is a selective force and that large, brightly colored guppies are more conspicuous to predators. Based on that, what would predict the guppies will look like in the pool with high predation after 10 generations? A) They should be smaller and not very brightly colored B) They should be large and brightly colored C) They should be very small and very brightly colored D) They should be very large but not very brightly colored
A) They should be smaller and not very brightly colored
Select all of the following that must be present for natural selection to occur and cause evolutionary change in a population. A) Variation must have a genetic basis B) Variation must exist among individuals C) Variation must result in differences in the number of offspring surviving in the next generation D) Variation must be the result of environmental differences
A) Variation must have a genetic basis B) Variation must exist among individuals C) Variation must result in differences in the number of offspring surviving in the next generation
For a gene with two alleles, what equation represents the sum of all gene frequencies? A) p+q=1 B) p+q=2pq C) p+q+pq=1 D) p+q=2
A) p+q=1
For insect populations to become increasingly resistant to pesticides A) resistance must be genetic B) selection must occur C) resistance must have no effect on fitness D) Hardy-Weinberg equilibrium must be present
A) resistance must be genetic B) selection must occur
Select all of the following that are examples of non-random mating A) selection of mates with dissimilar phenotypes B) drifting of gametes far from their origin C) selection of mates with similar phenotypes D) non-preferential selection of mates
A) selection of mates with dissimilar phenotypes C) selection of mates with similar phenotypes
Select the conditions that must be met for a population to be in Hardy-Weinberg equilibrium. A) the population is very large B) Migration occurs frequently C)No new mutations occur D) Mating is random E) Natural Selection Occurs
A) the population is very large C) No new mutations occur D) Mating is random
For a gene with two alleles, A and a, with allele frequencies given by p and q respectively, identify the chance that an offspring will inherit the following combinations of alleles in a population that is in Hardy-Weinberg equilibrium. AA Aa aa
AA = p^2 Aa = 2pq aa = q^2
For a gene with two alleles whose frequencies are p and q, the Hardy-Weinberg equation states that the genotypes that are possible for the population are p^2+2pq+q^2, which is equal to A) p^2+q^2 B) (p+q)^2 C) q-p D) p^2-q^2
B) (p+q)^2
Select all of the following events that could lead to a population bottleneck. A) Colonization of an island by a small number of individuals B) A natural disaster such as an earthquake or flood C) Migration between two neighboring populations D) Human destruction of habitat E) An infectious disease that kills a large proportion of the population.
B) A natural disaster such as an earthquake or flood D) Human destruction of habitat E) An infectious disease that kills a large proportion of the population.
Select the observations that would indicate that a population is deviating from Hardy-Weinberg equilibrium. A) The frequency of genotype HH is equal to p^2, where p is the frequency of H B) Allele frequencies are changing between generations C) Phenotypic frequencies are different than those predicted by the Hardy-Weinberg equation because one of the alleles is dominant over another D) Genotype frequencies do not match those predicated by the Hardy-Weinberg equation based on existing allele frequencies.
B) Allele frequencies are changing between generations D) Genotype frequencies do not match those predicated by the Hardy-Weinberg equation based on existing allele frequencies
Which of the following accurately describes the rates of variation in different parts of the human genome, as determined by the 1000 genomes project? A) The entire human genome appears to have low levels of variation B) Certain parts of the human genome contain more variation than others C) The genome of a single individual exhibits uniform variation, however, the amount of variation differs substantially between different individuals
B) Certain parts of the human genome contain more variation than others
Which type of selection favors individuals at one extreme of a phenotypic range who have greater reproductive success in a particular environment? A) Stabilizing Selection B) Directional Selection C) Balancing Selection. D) Disruptive Selection
B) Directional Selection
In theory, if mutation rates were high enough, alleles could be maintained in a population A) If the population size is small B) Even if the alleles are not favored by natural selection C) Only if the alleles are favored by natural selection
B) Even if the alleles are not favored by natural selection
Which of the following is true of evolutionary forces in natural populations? A) Evolutionary forces have no affect on allele frequencies in natural populations B) Evolutionary forces can alter allele frequencies in natural populations
B) Evolutionary forces can alter allele frequencies in natural populations
Based on genome sequencing, what is the level of variation in the genomes of fruit flies in natural populations ? A) Fruit fly genomes have very low levels of variation, except for a few very important genes, such as those involved in development B) Fruit fly genomes have extensive variation C) Fruit fly genomes have very low levels of variation
B) Fruit fly genomes have extensive variation
The evolutionary process that prevents the elimination of less fit alleles by reintroducing these alleles into populations is A) Mutation B) Gene Flow C) Natural Selection D) Random Mating
B) Gene Flow
Different alleles of genes are found within different individuals of a population. This is known as A) Genetic Drift B) Genetic Variation C) Natural Selection
B) Genetic Variation
Gene flow may: A) maintain Hardy-Weinberg equilibrium B) Promote evolutionary change C) Remove alleles from a population D) Introduce new alleles to a population E) Reduce evolutionary change
B) Promote evolutionary change C) Remove alleles from a population D) Introduce new alleles to a population E) Reduce evolutionary change
Which are true of antibiotic resistance? A) Humans have not impacted this process B) Resistance initially was due to a random mutation C) Increased resistance is due to selection
B) Resistance initially was due to a random mutation C) Increased resistance is due to selection
Genetic drift has a greater impact on which of the following: A) Large Populations B) Small Populations C) Medium Sized Populations
B) Small Populations
The prevalence of disorders such as polydactylism among some Amish populations in the United States is best explained by which of the following? A) Diversifying Selection B) The Founder Effect C) The Bottleneck Effect D) Negative frequency-dependent selection
B) The Founder Effect
Which of the following is an example of heterozygote advantage? A) Birds who lay an intermediate number of eggs have higher fitness than birds who lay either too many or too few eggs. B) The allele that causes sickle-cell anemia in homozygous confers resistance to malaria in heterozygotes C) Strains of colonial bent grass growing on soil contaminated with heavy metals tend to have intermediate levels of a resistance allele
B) The allele that causes sickle-cell anemia in homozygous confers resistance to malaria in heterozygotes
What can likely happen to uncommon alleles in small, isolated populations as a result of genetic drift? A) They are likely to increase in frequency B) They are likely to be lost C) They are likely to increase in heterozygotes D) They are likely to form the next generation
B) They are likely to be lost
Consider two populations (Population A and Population B) of the same plant species and the gene Xx. Researchers discover that there is constant flow of the x allele from population B into population A. This allele happens to be detrimental to individuals in population A because of the local soil conditions. In this case gene flow A) is strongly promoting evolutionary change B) appears to be constraining evolutionary change C) has a random effect on evolutionary change
B) appears to be constraining evolutionary change
We know that selection can occur based on climatic conditions, because biologists have found that A) the size of populations at southern latitudes is often higher B) enzyme allele frequencies can vary with geographic latitude C) different species are found at different latitudes
B) enzyme allele frequencies can vary with geographic latitude
Consider a gene with two alleles, one dominant, and the other recessive. If this population is in Hardy- Weinberg equilibrium with respect to this gene, what would happen to the dominant allele from generation to generation? A) its frequency will slowly decrease B) its frequency will remain unchanged C) its frequency will slowly increase
B) its frequency will remain unchanged
For a gene with two alleles, B and b whose frequencies are and q respectively, the probability that an individual receives a B allele from its mother and a B allele from its father is which of the following? A) p B) p^2 C) 2p D) 2pq
B) p^2
In a population of seahorses, red seahorses on average produce 125 offspring and brown seahorses produce 75 offspring. What is the fitness of the brown phenotype? A) 0.4 B) 1.4 C) 0.6 D) 1
C) 0.6
Select all fo the following that increase the chances of genetic drift in a population A) Migration into a population occurs B) Natural Selection is acting upon the population C) A few individuals of a population become isolated D) A population becomes very small E) Only a few individuals contribute gametes to the next generation
C) A few individuals of a population become isolated D) A population becomes very small E) Only a few individuals contribute gametes to the next generation
Which fo the following are findings of the 1000 Genomes Project? A) A surprisingly small number of insertions/deletions (less than 1,300) B) An average of 3,000-4,000 alleles that rendered genes inoperative per individual C) A large of SNPs among the different individuals (about 14 million) D) Substantial differences in the amount of variation in different parts of the genome E) An average of about 50-100 alleles associated with known inherited disorders per individual
C) A large of SNPs among the different individuals (about 14 million) D) Substantial differences in the amount of variation in different parts of the genome E) An average of about 50-100 alleles associated with known inherited disorders per individual
The allele for the sickle cell mutation is most common in A) America B) Northern Africa C) Central Africa D) Southern Africa
C) Central Africa
What term quantifies reproductive success of a phenotype? A) Competition C) Fitness B) Evolution D) Hardy-Weinberg Equilibrium
C) Fitness
Which of the following agents of evolutionary change occurs when alleles move from one population to another? A) Assortative Mating B) Natural Selection C) Gene Flow D) Mutations
C) Gene Flow
If population 1 is in Hardy-Weinberg Equilibrium such that p=0.7 and q=0.3, select all of the following that would result if mating began to occur with the adjacent population 2 in which p=0.1 and q=0.9. A) Population 2 will stay in Hardy-Weinberg equilibrium B) In population 1, p will increase C) In population 2, p will increase D) In population 1, q will increase E) Population1 will shift out of Hardy-Weinberg equilibrium
C) In population 2, p will increase D) In population 1, q will increase E) Population1 will shift out of Hardy-Weinberg equilibrium
How does genetic drift affect allele frequencies in a population? A) It eliminates advantageous alleles from the population B) It eliminates deleterious alleles from the population C) It changes allele frequencies without regard for their fitness D) It changes allele frequencies in a nonrandom way
C) It changes allele frequencies without regard for their fitness
In low-predation environments, South American guppies that produce the most offspring possess which of the following traits? A) Large size; drab coloration B) Small size; gaudy coloration C) Large size; gaudy coloration D) Small size; drab coloration
C) Large size; gaudy coloration
Which evolutionary mechanism causes beneficial traits that are heritable to become more common in a population? A) Horizontal Gene Transfer B) Non-random Mating C) Natural Selection D) Genetic Drift E) Migration
C) Natural Selection
Ground finches with large bills are favored during times of drought, while ground finches with small bills are favored during times when water is abundant. This is an example of A) Stabilizing Selection B) Balancing Selection C) Oscillating Selection D) Diversifying Selection
C) Oscillating Selection
How can the founder effect cause a previously rare genetic disorder to become common in the new population? A) Natural selection affects large populations more dramatically than it affects small populations B) New mutations are more likely to arise in small populations than in large populations C) The allele frequencies in the founding members of the population differ from the allele frequencies in the original large population D) Natural selection affects small populations more dramatically than it affects large populations
C) The allele frequencies in the founding members of the population differ from the allele frequencies in the original large population
The most fit phenotype produces, on average, which of the following ? A) The most physically fit offspring B) The healthiest offspring C) The greatest number of surviving offspring
C) The greatest number of surviving offspring
If a trait is subject to negative frequency-dependent selection individuals with which form of the trait that will have the highest fitness? A) Those with the common form of the trait B) Those with the intermediate form of the trait t C) Those with the rare form of the trait
C) Those with the rare form of the trait
In genes that are epistatic in nature A) selection on one allele would have no effect on other alleles B) certain alleles can never confer a selective advantage C) an allele's selective advantage may vary from one individual to another based on their genotype D) an allele's selective advantage will always be different in different individuals
C) an allele's selective advantage may vary from one individual to another based on their genotype
Similar to humans, fruit flies A) exhibit very low levels of variation in their genome B) exhibit uniform levels of variation across their entire genome C) exhibits much higher levels of variation in certain parts of their genome
C) exhibits much higher levels of variation in certain parts of their genome
In nature, mutation rates are usually ________ to maintain alleles that are not favored in a population by natural selection. A) often able B) too high C) not high enough
C) not high enough
In frequency-dependent selection: A) the fitness of a phenotype on the frequency of matings between individuals with that phenotype B) the fitness of a phenotype depends on the frequency of mutations leading to that phenotype C)the fitness of a phenotype depends on its frequency in the population
C) the fitness of a phenotype depends on its frequency in the population
Which of the following processes can be used to identify alternate forms of enzyme encoding genes? A) Chromatography B) Centrifugation C) Population Simulations D) Electrophoresis
D) Electrophoresis
What conclusion can be drawn from the observation that a population is not in Hardy-Weinberg equilibrium? A) Genotype frequencies but not phenotype frequencies are the same from one generation to the next B) The population is isolated from other populations of the same species C) Allele frequencies are stable from one generation to the next D) Evolutionary forces are affecting the population
D) Evolutionary forces are affecting the population
What type of selection favors common phenotypes and tends to eliminate variation? A) Directional Selection B) Oscillating Selection C) Negative frequency-dependent selection D) Positive frequency-dependent selection
D) Positive frequency-dependent selection
The phenotype frequency is calculated by dividing the total number of individuals with a particular phenotype by which of the following? A) The total number of alleles in that population B) The total number of heterozygous individuals in that population C) The total number of homozygous individuals in that population D) The total number of individuals in that population
D) The total number of individuals in that population
Assortative mating changes ____________ frequencies but does not change ____________ frequencies. A) allele; heterozygote B) genotype; heterozygote C) allele; homozygote. D) genotype; allele
D) genotype; allele
Natural Selection results in a population better adapted to its environment because A) it increases genetic diversity B) it decreases genetic diversity C) it causes new mutations to occur result in better adaptation to the environment D) only individuals who are well adapted to the environment contribute their alleles to the next generation
D) only individuals who are well adapted to the environment contribute their alleles to the next generation
The low level of genetic diversity among northern elephant seals is best explained by which of the following? A) migration B) natural selection C) the founder effect D) the bottleneck effect
D) the bottleneck effect
In E. coli, the alleles for the enzyme 6-PGD only have a selective advantage if A) gluconate is absent B) competition for gluconate is high C) the biochemical pathway for gluconate metabolism is interrupted D) the gene for the alternative enzyme is nonfunctional
D) the gene for the alternative enzyme is nonfunctional
A sudden and permanent change in the environment can lead to a type of natural selection called _______________.
Directional Selection
Suppose that a population of finches migrates to a small island where most of the seeds are large. On the island, birds with large beaks are more likely to survive, and over time, the mean beak size of the population increases. What type of natural selection is this?
Directional selection
________________ mating is a type of non-random mating in which phenotypically different individuals tend to mate more often. This produces an excess of heterozygotes.
Disassortative
Beaks in African black-bellied seed cracker finches are small or large, but not intermediate in size. This is an example of ___________ selection.
Disruptive
If individuals with rare phenotypic variants tend to have the highest fitness for a particular trait, the trait is likely subject to A) Sexual Selection B) Stabilizing Selection C) Diversifying Selection D) Negative heterozygote advantage E) Negative frequency-dependent selection
E) Negative frequency-dependent selection
Birds that lay intermediate numbers of eggs have greater fitness than birds that lay either too many or too few eggs. A) Directional B) Disruptive C) Balancing D) Sexual E) Stabilizing
E) Stabilizing
True/ False: Genetic drift causes alleles that increase fitness to become more common in a population.
False
True/False: Mutation and gene flow are equally important in determining how allele frequencies change
False
Random changes in allele frequencies in small populations are known as ______________________.
Genetic Drift
The theory of ________________ proposes that variation among individuals is not created by experience, but is the result of preexisting genetic differences.
Natural Selection
____________ selection is a process that can lead to change, and __________ is the outcome or record of change over time.
Natural; Evolution
The field of biology that studies the properties of genes is ______________________________.
Population Genetics
The type of selection demonstrated in the figure showing a fish with a rare phenotype attracting the attention of a predator is called _________ frequency-dependent selection.
Positive
__________________ selection favors individuals with intermediate phenotypes and selects against individuals with extreme phenotypes.
Stabilizing
True or False: Genetic drift, mutations, and non-random mating are three agents that can act to produce evolutionary changes in a population.
True
The term heterozygote _____________ refers to situations in which heterozygotes are more fit then either homozygotes.
advantage
Genetic _________ can likely play a role in large populations that were small at some point in their existence.
drift
If a population is in Hardy-Weinberg equilibrium, the allele ___________ of two alleles for a given trait can be calculated from phenotypic frequencies.
frequencies
Evolutionary change cannot occur in populations with no _______________ variation.
genetic
Natural populations exhibit significant ______________ and phenotypic variation.
genetic
In field experiments, South American guppies transplanted from ____________ predation environments to ____________ predation environments experienced rapid evolutionary change, becoming brightly colored and greater in size.
high; low
According to the theory of blending inheritance, offspring were expected to be phenotypically ____________ relative to their parents, which would dilute any new genetic variants.
intermediate
Hardy-Weinberg equilibrium requires that the population size is ___________ and that mating is _______________.
large; random
Female water striders who are larger in size lay more eggs but die younger and have less mating opportunities than intermediate-sized female water striders. As a result, larger female water striders have a _________ fitness than intermediately sized ones.
lower
Charles Darwin referred to evolution a "descent with ___________."
modification
Changes in allele frequencies within a population may result from ______________, which are changes in the nucleotide sequences of an organism's DNA.
mutations
In ___________ frequency-dependent selection, individuals whose resource requirements are rarer have fewer competitors for resources than individuals whose resource requirements are more common.
negative
In ____________ frequency- dependent selection, as rare genotypes become increasingly common, their selective advantage decreases. In ____________ frequency-dependent selection, as common genotypes become increasingly rare, their selective advantage decreases.
negative; positive
The theory of natural ________ as a mechanism of evolution was proposed by Charles Darwin.
selection
Genetic drift is more likely to overwhelm natural selection when populations are ____________.
small
Selection for speed in thoroughbred horses has removed genetic ___________ from the population at a faster rate than mutation can replace it.
variation