Bio 1407 Ch. 12. The forces of evolutionary change

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If the frequency of a homozygous recessive genotype is known for a population, what can then be determined using the Hardy-Weinberg equation

allele frequency

Balanced polymorphism means that multiple ________ of a gene persist in a population at more or less constant frequencies indefinitely

alleles

To calculate an allele frequency, you should divide the number of copies of that allele by the total number of ______ in the population for that gene.

alleles

The genetic contribution of an organism to the next generation is referred to as

fitness

In sexual selection, when females choose high-quality males for mates

fitness of the female increases.

Select all of the following that are true about natural selection

occurs due to variation in environmental factors reproductive success of individuals differs

What is the genotype frequency of CC if 320 individuals have the genotype CC in a population of 2,000 individuals

0.16

In a population of 100 individuals, 36 of the individuals are homozygous recessive (aa) for a particular gene. What is the frequency of that genotype

0.36

Use the equation p2 + 2pq + q2 = 1.0 to solve the following problem. In a population of 100 squirrels there are 64 black ones, and the remaining are white. Black (B) is the dominant allele, and white (b) is the recessive allele. If the population is in Hardy-Weinberg equilibrium, what is the frequency of the black squirrels that are heterozygous (Bb) for their coat color

0.48 Reason: The frequency of the white genotype (q2) is 0.36 (36/100), and therefore, the frequency of the b allele is q = 0.6. Then, because p = 1 - q, p = 0.4. The frequency of the heterozygous genotype is 2pq, and 2(0.6)(0.4) = 0.48.

What can prevent natural selection from producing the most useful trait in a species

A population is limited by the alleles present in its gene pool.

How might a change in the environment affect natural selection

A trait that was adaptive may become poorly adapted in the changed environment.

Independently of Charles Darwin, what other scientist proposed natural selection as a driving force for evolution

Alfred Wallace

Select all of the following that are misconceptions about evolution and natural selection

Biological evolution explains the origin of life. Natural selection is a random process.

How did natural selection shape the evolution of finches on the Galápagos Islands

Birds with different heritable differences were able to better survive and reproduce in different habitats

Who was one of the first scientists to suggest that species arose from ancestors and were changing

Buffon

In 1859, ______ published his book titled On the Origin of Species that underlies many principles of modern life science.

Charles Darwin

A book written by Thomas Malthus that influenced Charles Darwin's formulation of natural selection was titled

Essay on the Principle of Population.

As part of his voyage on the Beagle, Darwin spent about 5 weeks off the coast of Ecuador making observations on the

Galápagos Islands.

Darwin collected birds from the _______ Islands and took them back to England to study, where John Gould identified 13 species of birds called ______

Galápagos; finches

Random mating, a large population, and no mutation, selection, migration, or nonrandom mating are all assumptions of

Hardy-Weinberg equilibrium.

In regions of the world where malaria is prevalent, why do people that are heterozygous for the sickle cell allele have greater fitness than people who are homozygous for the normal hemoglobin allele

In heterozygotes, the sickled red blood cells decrease the spread of the parasite that causes malaria

Geological processes that occur today also occurred in the past, producing changes to Earth over time. This theory was proposed by ______ and is referred to as ______.

James Hutton; uniformitarianism

The idea that organisms could change their body form by repeated use of their body parts and that these changes could be passed to the next generation was introduced by

Lamarck.

What publication did Darwin read during his voyage on the HMS Beagle that convinced him of uniformitarianism and the old age of the Earth

Lyell's Principle of Geology

Select all the reasons why males usually show the greatest effects of sexual selection

Males must compete for access to females. Females have a high investment in reproduction.

At the time On the Origin of Species was written, what ideas conflicted with Darwin's ideas about evolution

Many people believed in the separate special creation of different species, and that species did not change after creation

Select observations and inferences that Charles Darwin made in support of natural selection

More individuals are born than can survive to reproduce. Natural selection can change the characteristics of a population over many generations. Some individuals survive due to their inherited characteristics, making them more likely to reproduce. Organisms are varied and some variations are inherited. There is competition among individuals for limited resources.

Select the true statement about mutation and natural selection

Natural selection acts on existing mutation.

Select the correct statement about natural selection

Natural selection does not have a goal of a perfect organism

Select all the ideas that were considered fundamental principles in explaining the diversity of life before the late 1800s

Organisms arose by special creation and did not change. Members of a particular species are identical in form and capacity.

What is a common misconception about natural selection

Organisms evolve the traits they need and lose the traits they don't need

Select all the statements that describe Lamarck's ideas about the origin of species

Organisms that use a body part repeatedly increase their abilities. Any physical changes that happen to the parents during their lives can be passed on to the next generation.

In some areas where cholera is common, why is the cystic fibrosis allele maintained in the population

People heterozygous for the cystic fibrosis allele have a fitness advantage

Select implications of Conover's and Munch's studies on selective forces of fish harvesting

Protecting the largest fish from harvest would help favor fast-growing fish. Fisheries would benefit from both a minimum and maximum size limit for harvest.

Select all the correct examples of artificial selection

The different breeds of domesticated dogs have been produced using artificial selection. Darwin raised and developed several breeds of pigeons using artificial selection. Broccoli, cauliflower, and kale were created by artificial selection of wild mustard

Before the late 1800s, how did some scientists explain the presence of fossils without denying a creator

The fossils could be explained using religious stories

Select all the reasonings of Charles Darwin that were influenced by Thomas Malthus's essay

There is variation in a population. More individuals are born into a population than the habitat can support. Some individuals in a population are better able to obtain resources than others.

Whose essay, describing how factors limit human population size, influenced Charles Darwin's ideas about variation and survival among individuals in a population

Thomas Malthus

What is an example of the founder effect

a few birds colonizing an isolated island

Select all the examples that reflect a fitness greater than zero

a male spider that is eaten by the female during mating, but that fathers 20 offspring a penguin that has one chick that survives to reproduce a jellyfish with a thousand offspring, 50% of which reach adulthood

A gene pool is the collection of all of the genes and alleles of

a population

Which of the following organisms has the highest fitness

an insect that produces 6 young and then dies

Select all of the following that are examples of sexual dimorphism

antlers on male deer females that look drab compared to males with showing feathers large size and snout of male elephant seals compared to female elephant seals

In the state of Hardy-Weinberg equilibrium, allele frequencies

are not changing

Broccoli, brussels sprouts, cauliflower, kale, and cabbage come from the wild mustard plant that humans have influenced over hundreds of years. The process that resulted in these five species is

artificial selection.

If humans are involved in perpetuating desired traits in organisms, the result is

artificial selection.

________ selection occurs when humans select for desirable characteristics in crosses of dogs, horses, or other organisms, whereas ________ selection occurs when environmental factors select for adaptive traits

artificial, natural

The average rate of mutation is around one DNA sequence change per ______ base pairs

billion

If two species that live on opposite sides of the planet share common characteristics and live in similar habitats, then these two species have undergone

convergent evolution.

Migration of individuals from one population to another

creates gene flow between populations.

Migration between populations will tend to

decrease genetic differences between the populations

The graph shows that when large fish are harvested from experimental tanks, the average weight of individuals ______ over subsequent generations, and the growth rate of these fish is ______

decreases; slower

The unity and diversity of life can be explained by

descent from a common ancestor

Gradual genetic changes in organisms from an ancestral species describes

descent with modification.

Descent with modification describes the process of

evolution

One definition of ______ is "changes in traits from generation to generation."

evolution

is defined as a change in allele frequencies in a population over time

evolution

In 1858, Darwin received a manuscript from Alfred Russel Wallace describing what similar idea of Darwin's

evolution by natural selection

If the environment changes, a trait that was adaptive may become nonadaptive or costly, demonstrating that

evolution continuously shapes populations.

True or false: Charles Darwin was the first to attempt to explain how the diversity of life arose

false

True or false: The goal of natural selection is to produce perfect organisms

false

How does natural selection act to change allele frequencies

favors phenotypes that increase reproductive success

Disruptive selection is a mechanism of natural selection that

favors two or more extreme phenotypes in a population.

What describes how genetic drift occurs

gain or loss of alleles by chance

While serving as a collector aboard the HMS Beagle, Darwin

gathered many observations that would later help shape his theory of evolution.

________ flow is the movement of individuals or gametes into or out of a population

gene

A precise definition of evolution is the

genetic change in a population over multiple generations.

Lyell's idea about fossils and the age of the Earth led to the conclusion that

gradual changes occurred in some organisms and that these could be preserved in the fossil record.

As proposed by James Hutton, the theory of uniformitarianism states that

gradual geological processes such as erosion and sedimentation that act in modern times also occurred in the past

Select all of the following that are examples of the bottleneck effect

greater prairie chickens North American bison

Evolutionary theory

has developed over several centuries.

What is a mechanism by which harmful alleles can be maintained in a population even though homozygous recessive individuals have greatly reduced fitness

heterozygote advantage

Carriers of cystic fibrosis have greater fitness in areas where cholera is common, which is an example of

heterozygote advantage.

In areas of Africa where malaria is common, the prevalence of the sickle cell allele is higher due to

heterozygote advantage.

Which two of the following was Charles Darwin not able to explain or understand with respect to his ideas on natural selection as a force of evolution

how heritable traits were passed from one generation to the next the source of variation within populations

Although Darwin proposed that natural selection acted on heritable traits, Darwin did not understand

how heritable traits were shuffled and passed on between generations.

Gregor Mendel's main contribution was to solve the puzzle of

how traits are inherited

When allele and genotype frequencies are not changing between generations, the population is said to be

in Hardy-Weinberg equilibrium.

Select all the ways that the Hardy-Weinberg equations can be used

indicate if evolution is occurring calculate genotype frequencies if allele frequencies are known calculate allele frequencies if genotype frequencies are known

Your friend thinks that her dog can evolve into a new species because it is so different than any other dog she has ever seen. You know that this is not possible because

individual organisms cannot evolve.

A(n) ______ does not evolve because alleles do not change; however, a(n) ______ can evolve because allele frequencies can change

individual; population

A population consists of

interbreeding members of the same species.

In a population undergoing stabilizing selection, what phenotype becomes more common over time

intermediate

Select all of the effects of gene flow

introduce new alleles into a population decrease regional differences in genetic diversity

Changes in allele frequencies in a population or species that occur over a relatively short time rather than millions of years is an example of

microevolution

The small, genetic changes that occur from generation to generation within a population or species are called

microevolution

Select all of the following that occur in natural populations and that violate the assumptions of the Hardy-Weinberg equilibrium

migration among populations occurs mating is often nonrandom allele frequencies can change due to chance events

In the 1930s, scientists unified natural selection and genetics into the

modern evolutionary synthesis.

Rock layers at the bottom of a geologic deposit are the

oldest

The entire collection of the genes and their alleles in a population is called the gene

pool

A difference in the appearance between males and females of a species is called

sexual dimorphism.

In a bird species, when females have inconspicuous coloration and males are brightly colored, this is an example of

sexual dimorphism.

What increases genetic variability within a species through shuffling and reshuffling of parental alleles to produce genetically different offspring

sexual reproduction

A type of natural selection that results from variations in the ability to obtain mates is referred to as

sexual selection

Species have undergone convergent evolution if they

share characteristics and evolved in similar environments

Genetic drift has a greater effect on

small populations

By the 1700s, fossil discoveries provided evidence that

species can change

An example of macroevolution would be the appearance of a new

species of finch.

When the intermediate phenotype of a trait is being selected for and the extreme phenotypes are being selected against, the population is probably undergoing

stabilizing selection.

A mutation can affect evolution in a species only if

subsequent generations inherit it.

Suppose the migration of a subset of the human population to a new area leads to relatively low genetic diversity in the new population. This is an example of

the founder effect.

Use the equations p + q = 1.0 and q = √q2q2 to solve the following problem. In a population of 200 rabbits, there are 18 individuals with short ears and the remaining have long ears. The long ear allele (L) is dominant to the short ear allele (l). What is the frequency of the L allele

0.7 Reason: The frequency of the homozygous recessive genotype ll can be calculated as 18/200 = 0.09, which is q2. Thus, q = the square root of 0.09, which is 0.3 and is the frequency of the l allele. Using p + q = 1, p = 1 - 0.3, or 0.7, which is the frequency of the L allele.

For a gene that has only two possible alleles with allele frequencies of p and q, the Hardy-Weinberg equilibrium states that p + q

1

What did Darwin's ideas suggest about humans, which was hard for some people at the time to accept

Humans are just another species subject to natural selection.

Select the five assumptions of the Hardy-Weinberg equilibrium that must be met to keep allele frequencies from changing

The population is large. No mutations occur. Mating is random. There is no migration into or out of the population. No natural selection occurs.

Select all the key properties of evolutionary adaptations

They can confer reproductive success. They are heritable.

What describes the founder effect

a small group of individuals establishes a new colony

When multiple alleles of a gene persist indefinitely in a population at more or less constant frequencies, then what is occurring

balanced polymorphism

Because genes do not "know" when to mutate, it follows that bacterial species with a resistance to an antibiotic must have had a mutation ______ exposure to the antibiotic.

before

Charles Darwin consulted John Gould about the birds that he had collected on the Galápagos Islands. Gould identified 13 distinct types of finches based on the birds'

bills

When a population's size drops rapidly over a short period, resulting in a loss of many alleles that were present in the larger ancestral population, this is referred to as the ________ effect

bottleneck

A type of genetic drift in which a population's size drops rapidly over a short period of time, causing the loss of many alleles, is called a

bottleneck effect.

Select all of the following that are true about the heterozygous genotype in the situation of heterozygote advantage

can contain harmful alleles has greater fitness than homozygous genotypes

Genetic drift is a change in allele frequencies that occurs by ______ and, unlike mutations, it tends to eliminate alleles from the population

chance

In sexual dimorphism, one sex is ______ than the other sex

different in appearance

Selection for one extreme phenotype in a population would be considered a type of natural selection called ______ selection

directional

The image shows an example of what type of natural selection

directional selection

When two phenotypic extremes of a trait are being selectively favored, then a natural population is undergoing _______ selection

disruptive

If a predator is more likely to prey upon fish that are brightest in color, then natural selection in this environment will favor

drabber fish

A genotype's ________ is the number of individuals with that genotype, divided by the total size of the population

frequency

In a population, each genotype's ______ is the number of individuals with that genotype, divided by the total size of the ______

frequency; population

In evolutionary terms, fitness of an organism is defined as an organism's

genetic contribution to the next generation.

A chance change in a population's allele frequencies, such as after a drastic reduction in population size, is the root of what force of evolution

genetic drift

A change in allele frequencies that occurs by chance and that tends to eliminate alleles in a population rather than increase diversity is called

genetic drift

The bottleneck effect is an example of what mechanism of evolution

genetic drift

The founder effect is an example of what mechanism of evolution

genetic drift

What evolutionary force has a greater effect on small populations

genetic drift

What mechanism of evolution accounts for the fact that the Ellis-van Creveld syndrome has a high incidence among the Amish

genetic drift

Which of the following are mechanisms of evolution

genetic drift and nonrandom mating

The modern evolutionary synthesis connects natural selection and

genetic variation that arises by mutation

Although the average mutation rate is 1 DNA sequence change per 1,000,000,000 base pairs, mutation is still significant enough to produce evolutionary change because

genomes are enormous and cell divisions occur frequently.

In the Hardy-Weinberg equilibrium, the terms p2, 2pq, and q2 refer to

genotype frequencies in a population.

Female birds of paradise mating with males that have the most brightly colored and showy plumage, which allows the alleles for those feathers to be passed on to the next generation, is an example of

intersexual selection.

Male bighorn sheep compete with other males for mating privileges and therefore exhibit ______. Female peahens select one of many male peacocks to sire their chicks, which provides an example of ______

intrasexual selection; intersexual selection

Mate choice, such as in sexual selection

leads to nonrandom mating.

In order for natural selection to take place, natural resources, like food and water, must be

limited

Fossils present in ______ layers of rock are older

lower

The principle of superposition explains the idea that ______ layers of rock, along with the fossils they contain, are older than the layers ______ them

lower; above

Darwin reasoned that the variety of finch species found on the Galápagos Islands descended from a common ancestor. He used the phrase "descent with ________" to describe gradual genetic changes from the ancestral type

modification

A ________ is a change in an organism's DNA sequence and is the raw material for evolution, because genes affect phenotypes and evolution acts on phenotypes

mutation

A(n) ________ is a change in a DNA sequence that occurs at random

mutation

According to the modern evolutionary synthesis, what creates the variation upon which natural selection acts

mutation

In real populations, what mechanism introduces new alleles into the gene pool and violates the assumptions of Hardy-Weinberg equilibrium

mutation

New alleles that might allow a bacterium to become resistant to an antibiotic arise through

mutation

The only way that new genetic variants arise is through ______, which is the raw material of evolution

mutation

Select the example of a mutation that could result in evolutionary change

mutation in the chromosome structure of an egg cell before fertilization

Charles Darwin's book titled On the Origin of Species proposed ______ as an evolutionary mechanism

natural selection

Directional, disruptive, and stabilizing are all types of ______, in which certain phenotypes are favored over others

natural selection

What occurs when environmental factors cause the differential reproductive success of individuals with particular genotypes

natural selection

When the process of ______ takes place over billions of years, a simple organism can give rise to many different types of species, such that all species are related to each other through evolution

natural selection

Select all of the following that are mechanisms of evolution and that can alter allele frequencies

natural selection gene flow mutation

What neither decreases nor increases reproductive success of an organism

neutral variation

In artificial selection, mating is

nonrandom

Sexual selection is a special form of natural selection in which individuals vary in ability to

obtain mates

Select all of the following that Charles Darwin observed during his voyage on the Beagle

plants and animals on the Galápagos Islands land altered by forces, such as earthquakes and erosion forest plant fossils mixed in with ocean sediments

After reading Malthus's essay, Darwin realized that

poorly adapted individuals would not survive if resources were limited.

Evolution can be defined as a change in allele frequencies within a(n)

population

Interbreeding members of the same species compose a

population

Fitness depends on which of the following

proportion of offspring that survive to reproduce number of successful reproductive efforts in lifetime ability to survive long enough to successfully reproduce

In the bottleneck effect, what alleles are lost when a population's size drops is

random

Fitness of an organism depends on

reproduction

Hardy-Weinberg equilibrium is seldom seen in natural populations because

selection takes place in natural systems.

The drastic reduction in cheetah population size in the last 10,000 years and the resulting decrease in genetic diversity is an example of

the bottleneck effect

In a population of 1,000 individuals with a gene that has two alleles, there are 2,000 alleles total for this gene. If there are 800 copies of allele a, what is the frequency of allele a in the population?

0.4

There is a population of 100 diploid individuals with a gene that has 2 different alleles (B and b). If 180 of the alleles in the population are B, then the frequency of the allele B in that populations is ______.

0.9

Taking into account that natural selection resulted in the diversity of finches on the Galápagos Islands, rank the following in the order they occurred, beginning with the earliest event at the top

1. A few finches flew from the mainland to one island. 2. Most of the finches could only eat small seeds, but the island population outgrew the supply of small seeds. 3. Finches that could eat other foods survived and reproduced, while most of the birds that could only eat small seeds starved. 4. The finches that could eat other foods gradually made up more of the population.

Select all of the evidence supporting the fact that descent from a common ancestor resulted in the diversity of life

A diversity of organisms use the same chemical reactions to extract energy from nutrients. Different species have similar proteins and enzymes. Most life forms use the same genetic code for gene expression.

Identify the scientists and the important idea that they proposed about evolution

Buffon Closely related species arise from a common ancestor and are changing. Lyell Natural processes are slow and steady, and the Earth is much older than 6,000 years. Darwin Variation exists in a population and new species arise when natural selection acts on the variation. Lamarck Repeated use of a body part increases an organism's abilities, and this change during a lifetime passes to the next generation

What is an example of a human disease that persists in the population because individuals are typically affected after reproductive age

Huntington disease

A(n) ______ is a feature that provides a selective advantage to an organism because it improves its ability to survive and reproduce

adaptation

The ability of an organism to camouflage with its environment is an example of a(n)

adaptation

Structures, behaviors, and physiological processes that are heritable and that contribute to the reproductive success of an organism are called

adaptations

The number of copies of an allele divided by the total number of alleles in a population is the

allele frequency

What theory proposes that most geological formations were formed by brief, violent upheavals such as floods, earthquakes, and volcanic eruptions

catastrophism

The theory of ______, proposed by Georges Cuvier, proposed that ______ were responsible for most geological formations

catastrophism; brief, violent, global upheavals

What is an example of microevolution?

change in allele frequencies in a population from generation to generation

Who was a collector and captain's companion on the five-year voyage of the HMS Beagle

charles darwin

Select all the factors that could limit the human population size, as stated in Malthus' Essay on the Principle of Population

food availability disease war

Select the name of the scientist who first stated that the Earth was older than 6,000 years

lyell

The appearance of a new species of oak tree would be called a(n) ______ event

macroevolutionary

An Austrian monk named ______ was solving the puzzle of inheritance at the same time Darwin was proposing natural selection

mendel

Artificial selection is also called

selective breeding

The term ______ means that a feature or features of an organism neither increase nor decrease reproductive success

selectively neutral

What type of reproduction amplifies genetic variation by shuffling alleles and producing genetically different offspring

sexual

Cuvier thought that lower layers of rock were older than those above them. This principle describes

superposition

Prior to newer geological ideas of the 1700s and later, many people believed that Earth was relatively ______ and that species were ______

young; unchangeable

Darwin noted that natural selection occurs because

adaptive traits that are heritable can pass to offspring and increase their survival and reproduction

Selection of dairy cows that produce more milk for human consumption is an example of ______ selection, and selection of light-colored moths over dark-colored moths by a bird predator is an example of ______ selection.

artificial; natural

Natural selection can act to eliminate

nonadaptive phenotypes.


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