BIOL 1030 Chapter 13 Homework Questions

In human gamete production there is an average of _____ crossover events per chromosome pair. 2-3 10+ 5-6 9-10 0-1

2-3

Color is an inherited trait in beetles. If brown beetles move into a population from a nearby island, which of the following statements is correct? A) Gene flow causes the frequency of the brown allele to increase. B) Natural selection causes the frequency of the brown allele to increase. C) This is an example of genetic drift. D) Gene flow causes the frequency of the green allele to increase. E) Natural selection causes the frequency of the green allele to increase.

Gene flow causes the frequency of the brown allele to increase.

Which of the following events could NOT be caused by a population bottleneck? Increased population size Changes in allele frequency Reduction in genetic variability Loss of alleles

Increased population size

Which example below presents a misconception about how antibiotic resistance develops? A) If people do not take the full antibiotic treatment as prescribed, some microbes carrying the potential for resistance may be more likely to survive and prosper. B) Individual bacteria and viruses become immune to antibiotics after they are exposed to them. Eventually the antibiotics are useless. C) Antibiotics are often added to livestock feed. This selects for antibiotic resistance in bacteria found in and around livestock facilities. Thus, many meat products sold in supermarkets contain antibiotic-resistant bacteria. D) Heavy use of antibiotics in hospitals produces selection pressure for antibiotic resistance in resident bacterial populations.

Individual bacteria and viruses become immune to antibiotics after they are exposed to them. Eventually the antibiotics are useless.

Natural selection and evolution are two terms that are sometimes confused, even by first year biology students. What is the relation between natural selection and evolution? A) Natural selection happens over long periods of time; evolution is a short-term process. B) Any phenomenon that causes evolution is natural selection. C) Natural selection is one of several mechanisms of evolution. D) When natural selection is occurring, evolution is not, and vice versa.

Natural selection is one of several mechanisms of evolution.

Which would be a good example of intrasexual selection? A) Female birds discriminate among potential mates and choose their partners based on the quality of the song. B) Bright-colored male bluebirds are more attractive to mates than dull-colored individuals. C) Male elephant seals use their huge bodies to batter each other in battles for access to mates. D) Male elk suffer heavy wolf predation because of their large antlers, producing selection against increased antler size in the population

Male elephant seals use their huge bodies to batter each other in battles for access to mates.

Evolution that occurs by ___results in a change in a population's gene pool due to chance.

genetic drift

Under some conditions, heterozygotes have greater reproductive success than homozygotes. What is this called? incomplete dominance frequency-dependent selection heterozygote advantage polymorphism

heterozygote advantage

Two key observations underlying natural selection are that members of a population vary in their ___ and that all species can produce more offspring than the environment can support.

inherited traits

Darwin inferred that those organisms with traits best suited to the environment tend to leave more ___ than other members of a population.

offspring

In sexual selection, individuals with certain inherited characteristics are more likely to obtain mates than other individuals. This often results in ___, differences between the sexes in size, appearance, and behavior.

sexual dimorphism

Which of the following structures would be the LEAST likely to fossilize? bones shells of clams and snails skin teeth

skin

Suppose that, with regard to a particular gene with two alleles, A and a, we know that 60% of the alleles in the gene pool of a particular large population are A. We observe this population for five generations, during which we know that no mutation, selection, or migration has occurred. After this period, the frequency of the a allele is expected to be _____. 0.25 0.16 0.4 0.6

0.4

Suppose there is a population of 100 rabbits. In this population, 60 rabbits are FF, 20 are Ff, and 20 are ff. What is the allele frequency for the F allele in this population's gene pool? 0.5 0.6 0.7 0.8

0.7

Approximately one out of every 2,500 Caucasians in the United States is born with the recessive genetic disorder cystic fibrosis. According to the Hardy-Weinberg equilibrium equation, approximately how many people are carriers? 1 in 25 1 in 50 96 in 100 1 in 10

1 in 25

___ favors intermediate phenotypes, selecting against phenotypes at both ends of a range and reducing variation.

Stabilizing selection

___ is a type of sexual selection in which individuals of one sex (usually males) compete directly for mates. This may involve ritualized displays or physical combat.

Intrasexual selection

Which of these individuals is a homozygous genotype? AG Gg Aa AA aG

AA

Suppose that every few years, all people over 6 feet tall do not have any children. How will this affect the human population? A) It will increase in number since shorter people use fewer resources than taller people. B) Alleles that promote "tallness" will decrease in frequency. C) Gene flow will increase. D) Genetic drift will play less of a role in the evolution of humans. E) The mutation rate will increase.

Alleles that promote "tallness" will decrease in frequency.

Which best describes the fossil record? A) The fossil record is the sequence in which fossils are found in layers of sedimentary rock. It is chaotic (jumbled), making it difficult to find any consistent patterns in life's evolution. B) The fossil record is a database in which fossil names and dates are collected. C) The fossil record is a sequence of fossils arranged from oldest (top layers of rock) to youngest (bottom layers of rock). D) The fossil record is the highly ordered sequence in which fossils are found in layers of sedimentary rock.

The fossil record is the highly ordered sequence in which fossils are found in layers of sedimentary rock.

This unequal reproduction in a population leads to the gradual accumulation of ___to the environment.

adaptations

A(n) ___ is a group of individuals of the same species living in the same area that interact with each other.

population

Small lizards have difficulty defending their territory, but large lizards are more likely to be preyed upon by owls. Which type of selection would act on body size in these lizards under these conditions? Directional selection Disruptive selection Stabilizing selection

Stabilizing selection

In a species of snail, dark-shelled individuals are better hidden from bird predators in the shady forest, while light-shelled individuals are better hidden in well-lit brushy edge areas. If there were no areas of intermediate brightness in this habitat,which type of selection would act on shell color in these snails? Disruptive selection Stabilizing selection Directional selection

Disruptive selection

___ favors phenotypes at both ends of a range over intermediate phenotypes. This type of selection may occur when the habitat is varied.

Disruptive selection

All the genes in a population are that population's _____ gene pool fitness genotype phenotype Hardy-Weinberg

gene pool

The total collection of alleles in a population at a given time is the population's___

gene pool

Modern travel along with migration reduces the probability of _____ having an effect on the evolution of humans. natural selection mutation genetic drift gene flow disease

genetic drift

Which of the following are causes of evolutionary change? Select all that apply. genetic drift gene flow natural selection mutation

genetic drift gene flow natural selection mutation

The evolution of populations due to chance is genetic variation. genetic drift. natural selection. gene flow. has more effect in large populations than in small populations

genetic drift.

In Europe at the time Darwin voyaged on HMS Beagle, the popularly accepted explanation of the origin of Earth's plants and animals held that the various species __________. A) had been created rapidly by a divine creator a few thousand years before B) were all related to one another C) arose continually from nonliving materials by spontaneous generation D) had evolved from now-extinct organisms

had been created rapidly by a divine creator a few thousand years before

In a type of sexual selection often called ___, individuals of one sex (usually females) are choosy in selecting their mates. This choice is often based on the showy appearance or behavior of the male

mate choice

Homologous pairs of chromosomes are lined up independently of other such pairs during _____. metaphase I telophase II prophase II metaphase II anaphase I

metaphase I

Changes in allele frequencies in a population over time is ___

microevolution

Generation-to-generation change in the allele frequencies in a population is _____. natural selection microevolution genetic drift macroevolution mutation

microevolution

he phrase Darwin used to describe his broad theory of evolution is ''descent with ___

modification

A(n) ___ is a change in the nucleotide sequence of DNA.

mutation

Of the choices listed below, which contributes the most to genetic variation among individuals in most prokaryote species? mutation genetic drift crossing over independent assortment of homologous chromosomes

mutation

The original source of all genetic variation is __________. recombination natural selection mutation meiosis

mutation

Darwin proposed a mechanism for how evolution occurs, which he called

natural selection

Evolution that occurs by ___ results in nonrandom reproductive success and adaptive change.

natural selection

Crossing over, resulting in an increase in genetic variation, occurs between _____. A) sister chromatids of homologous chromosomes B) sister chromatids of nonhomologous chromosomes C) sex cells and somatic cells D) nonsister chromatids of homologous chromosomes E) nonsister chromatids of nonhomologous chromosomes

nonsister chromatids of homologous chromosomes

Genetic variation in a population of animals or plants depends mainly on which of the following? migration of genes among the chromosomes mutation sexual reproduction the organism being haploid

sexual reproduction

Organisms that possess homologous structures probably __________. share a common ancestor that also had this structure use these homologous structures for the same purpose live in a similar environment by chance had similar mutations in the past

share a common ancestor that also had this structure

Consider a hypothetical insect population of 100 individuals. Two equally represented alleles (A and a) exist for a particular gene. Which scenario is an example of microevolution in this population? A) The population is reduced in size due to loss of their food source. Fifty insects remain, and the two alleles are still present in their original proportions. B) The population is exposed to a toxin that kills individuals with the A allele. After exposure to the toxin the population has 25 surviving individuals, and 95% of them have the aa genotype. C) The population doubles in size, and the two alleles are maintained at their original proportions. D) Several insects migrate to a new location. The population is left with 80 insects, but the two alleles are still equally represented.

The population is exposed to a toxin that kills individuals with the A allele. After exposure to the toxin the population has 25 surviving individuals, and 95% of them have the aa genotype.

In a population with brown and green alleles for color, genetic drift A) has more effect on the evolution of a small population. B) occurs when individuals move into or out of a population, changing the allele frequencies in the population. C) has more effect on the evolution of a large population. D) always increases the frequency of brown alleles in the population. E) causes populations to become better adapted to their environments

as more effect on the evolution of a small population.

In natural selection, _____ determine which phenotypes are successful. A) catastrophes that reduce the population to a very small number of survivors B) chance events C) current conditions in the local environment D) future (anticipated) environmental conditions

current conditions in the local environment

A large population of mice is isolated on an island. There are two varieties of the mice, brown and gray. Their fur colors closely match the gray rock outcrops and brown soils of the island. Hawks are their main predators. This situation most likely reflects the outcome of __________. stabilizing natural selection directional natural selection genetic drift disruptive natural selection

disruptive natural selection

The ___of life arises from the adaptation of species to different habitats over long spans of time

diversity

The wing of a bat is homologous to the _____ of a whale. blowhole tail flipper baleen rib cage

flipper

Consider a population of birds living on an island. Suppose several individuals of the same species from a different population migrate to the island. Due to the arrivial of the new birds, the allele frequencies in the original population change. What mechanism of microevolution is at work in this example? natural selection gene flow genetic drift

gene flow

Evolution that occurs by ___ results in a change in a population's gene pool due to the movement of individuals into and out of the population

gene flow

The ease with which humans travel across the globe is likely to increase _____. mutation genetic drift gene flow natural selection

gene flow

A(n) ___ is an alternative version of a gene

allele

If color is an inherited trait in beetles, and birds are more likely to eat brown beetles than green beetles, A) this causes the population to evolve due to gene flow. B) the frequencies of the brown and green alleles will not change. C) the frequency of the green allele will increase. D) the frequency of the brown allele will increase. E) this causes the population to evolve due to genetic drift.

the frequency of the green allele will increase.

Genetic drift is a process based on _____. A) mutation B) immigration C) differential reproductive success correlated to the relationship between a phenotype and the environment D) emigration E) the role of chance

the role of chance

A mutation occurs when _____. some individuals leave more offspring than other individuals there is a change in the DNA sequence of a gene individuals enter a population individuals leave a population population sizes are small

there is a change in the DNA sequence of a gene

The first tetrapods (four-legged animals) were amphibians, which evolved from a specialized group of lobed-fin fish. An unusual fossilized animal (named Tiktaalik) was recently found; this animal possessed a mixture of fish and amphibian characteristics. What is the term used to describe such an intermediate organism? mutant homologous transitional form vestigial

transitional form

All of life is related through common ancestry, accounting for the ___ of life.

unity

Which of the following lists of assumptions was part of Charles Darwin's theory of natural selection? A) 1. Organisms vary in heritable ways. 2. Some traits improve the survival and reproduction of individuals who possess them. 3. Populations produce more offspring than their environment can support, so individual organisms must compete for limited resources. 4. Earth and its life are very old. B) 1. Earth and its life are very old. 2. Populations produce more offspring than their environment can support. 3. Organisms vary in heritable ways. 4. Mutation rates were higher in the past than they are now. C) 1. Populations produce more offspring than their environment can support, so individual organisms must compete for limited resources. 2. Some traits improve the survival and reproduction of individuals who possess them. 3. There is little genetic variability. 4. Organisms vary in heritable ways. D) 1. Organisms vary in heritable ways. 2. Populations produce more offspring than their environment can support, so individual organisms must compete for limited resources. 3. Some traits improve the survival and reproduction of individuals who possess them. 4. Mutations directly cause the changes in species.

1. Organisms vary in heritable ways. 2. Some traits improve the survival and reproduction of individuals who possess them. 3. Populations produce more offspring than their environment can support, so individual organisms must compete for limited resources. 4. Earth and its life are very old.

In a certain group of African people, 4% are born with sickle-cell disease, an autosomal recessive disorder. Heterozygous individuals not only don't have sickle-cell disease, but also are resistant to malaria. If this group is in Hardy-Weinberg equilibrium, what percentage of the population is heterozygous and resistant to malaria? 4% 16% 32% 80%

32%

Of the scenarios below, which represents the occurrence of evolution at its smallest scale? A) An individual organism begins as a single cell and develops into an adult, changing dramatically through a series of life stages. B) A pesticide spray is heavily used on a particular farm. Initially it kills 98% of the grasshoppers on contact. Over several generations, the local grasshopper population becomes resistant to the pesticide through inheritance of resistance alleles. Other nearby grasshopper populations do not change in any noticeable way. C) Over many thousands of years, the beak shape of a bird species changes to exploit a new food source. D) An adult human moves from near sea level to a city high in the Andes Mountains. Her physiology changes to improve her performance in the thin atmosphere.

A pesticide spray is heavily used on a particular farm. Initially it kills 98% of the grasshoppers on contact. Over several generations, the local grasshopper population becomes resistant to the pesticide through inheritance of resistance alleles. Other nearby grasshopper populations do not change in any noticeable way.

___ favors phenotypes at one end of a range and is common in periods of environmental change.

Directional selection

Which of the following is a true statement about Charles Darwin? A) He based his theory on the inheritance of acquired characteristics. B) He was the first to discover that living things can change, or evolve. C) He worked out the principles of population genetics. D) He proposed natural selection as the mechanism of evolution.

He proposed natural selection as the mechanism of evolution.

As proposed by Darwin, what sorts of traits are favored by natural selection? A) Any traits that are produced by mutation and can be inherited. B) Traits that reduce the number of offspring an individual produces, thus helping to reduce the struggle for existence in the next generation. C) Traits that reduce the mutation rate and cut down on unnecessary variation within populations. D) Heritable traits that help individuals survive and reproduce more successfully than others in the same population.

Heritable traits that help individuals survive and reproduce more successfully than others in the same population.

Why is natural selection considered to be the most important mechanism of microevolution? A) Natural selection always causes recessive alleles to increase in frequency in the population. B) Natural selection relies on chance events to produce adaptions in populations. C) Natural selection is the only mechanism that consistently leads to adaptive changes in populations. D) Natural selection allows individuals in a population to develop adaptations and thus evolve over their lifetimes.

Natural selection is the only mechanism that consistently leads to adaptive changes in populations.

Which of the following is a misconception regarding natural selection? A) There is a struggle for existence among individuals because organisms tend to produce far more offspring than the environment can support. B) Natural selection progressively refines organisms' adaptations, eventually leading to perfection. C) Individuals do not evolve; populations do. D) Natural selection can only act to diminish or amplify heritable traits.

Natural selection progressively refines organisms' adaptations, eventually leading to perfection.

A population of small fish lives in a lake with a sandy bottom. The major predator of these fish is a wading bird that hunts by sight. Most of the fish are light sandy brown, but about 10% are mottled. The color pattern is heritable. A construction company dumps a load of gravel in the bottom of the lake, giving it a mottled appearance. Which of these statements presents the most accurate prediction? A) According to the Hardy-Weinberg equilibrium, the ratios will not change. B) There is no way to guess the result, because evolution occurs at random. C) As the sand-colored fish are eaten, more will be produced to keep their frequency at 90%. D) The proportion of mottled fish will increase over time.

The proportion of mottled fish will increase over time.

What was significant to Darwin about the fauna and flora of the Galápagos Islands? A) The species were similar to South American species, indicating common descent, but they had been extensively modified and were well-adapted to island life. B) The organisms there were similar to fossils found elsewhere, indicating that the Galápagos chain held many ancient species. C) The organisms there were the same as those seen on similar island environments around the world D) The species on the Galápagos Islands were not similar to those anywhere else, indicating that they had been created specifically to inhabit this environment.

The species were similar to South American species, indicating common descent, but they had been extensively modified and were well-adapted to island life.

As in the previous question, suppose there is a population of 100 rabbits that have different fur patterns. In this population several generations ago, there were 60 FF rabbits, 20 Ff rabbits, and 20 ff rabbits. Over time, the population changed, and now there are 40 FF rabbits, 40 Ff rabbits, and 20 ff rabbits. Has microevolution occurred? Why or why not? Yes, because the allele frequencies have changed. No, because the number of ff rabbits has not changed. Yes, because time has passed. No, because the population size has not changed.

Yes, because the allele frequencies have changed.

Mutations are always __________. neutral a change in an individual's DNA good bad

a change in an individual's DNA

Natural selection is best described as _____. A) a creative force that efficiently develops the best and simplest solutions for all problems in nature B) a forward-looking process that anticipates future problems and designs the necessary tools to solve them through mutation C) a filtering process that fine-tunes the traits of populations by sorting among existing, randomly produced variations D) a completely random and unpredictable process of change, or evolution

a filtering process that fine-tunes the traits of populations by sorting among existing, randomly produced variations