Bio 1407 Ch. 12. The forces of evolutionary change
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.
