Bio Ch 15
In a very small population of birds, assume 5 out of 20 alleles are the type that code for blue feathers. What is the allele frequency of the "blue feather allele" in this population?
.25
According to the Hardy-Weinberg principle, if 75% of the alleles in the gene pool are A1 and 25% are A2, what is the proportion of individuals with genotype A1A2 in this population?
.375
Which trait is the best example of an adaptation?
A mutation resulting in a heat-resistant enzyme in a bacterium living in a hot spring
Which of the following is most likely to experience genetic drift?
A population of endangered birds that includes only five individuals
The gene pool for a particular gene is made up of
ALL genes that occur in population
A new predator is introduced to an area that can feed on any millipedes shorter than 200 millimeters. No millipedes that live in that area are longer than 15 millimeters. What will happen?
All millipedes will be potential prey.
A bird comes in a range of phenotypes, from white through gray to black. Disruptive selection favors the gray phenotype.
FALSE
Environmental change causes the heritable variations in individuals that natural selection acts upon.
FALSE
Genetic drift is more common in large populations than in small populations
FALSE
In a population, the most common phenotype represents the dominant allele
FALSE
In a single family, the parents have brown eyes but all five of their children have green eyes. This is an example of evolution
FALSE
Natural selection causes genetic changes in an individual
FALSE
The use of antibiotics caused the mutation that produced MRSA
FALSE
Which of the following mutations would increase evolutionary fitness?
One that increases the frequency of successful reproduction
Natural selection causes genetic changes in populations
TRUE
New individuals moving into an area and joining the breeding population are an example of gene flow
TRUE
Organisms that have the greatest reproductive success are considered the most evolutionarily fit.
TRUE
Which of the following can be measured to estimate an organism's evolutionary fitness?
The number of offspring it produces over its lifetime that survive to breed
evolution can be defined as
a change in the genetic makeup of a population over time.
Imagine a population of monkeys in South America whose habitat has been reduced to the point where only 20 individuals survive. This is an example of
a population bottleneck
evolution by natural selection is
a process that occurs as a result of differences in fitness.
nonliving components of environment
abiotic factors
population is defined as:
all individs of same species located in a given geographic region
In an equilibrium population
allele frequencies do not change
If two or more phenotypes in a population are both favored by selection, what is happening?
balanced polymorphism
In some butterfly populations, there are equal frequencies of alleles that code for black and yellow coloration. This is an example of
balanced polymorphism
When natural selection tends to split a population into two phenotypic groups, it is called
balanced polymorphism
multi-drug resistant bacteria
becoming more widespread
A bacterial allele that provides resistance to the antibiotic streptomycin is
beneficial to the cell in the presence of streptomycin.
The 30,000 elephant seals alive today are genetically very similar due to
bottleneck effect
As predator and prey species acquire new adaptations to help them survive the constant "arms race" between them, what evolutionary phenomenon is occurring?
coevolution
mutations
can be helpful, harmful, or neutral
gene flow
can spread certain alleles throughout a species.
Populations of organisms are constantly evolving, which means they are always
changing
The change in one population due to a change in another population is called
coevolution
When different species closely interact for an extended period of time and develop new adaptations in response to each other, it is called
coevolution
When one species evolves a new phenotypic feature and another species evolves new adaptations in response, it is called
coevolution
Imagine that a population of hummingbirds with an intermediate beak size develops longer beaks over time. This is an example of
directional selection
Suppose a population of mostly sand-colored crabs migrates from a sand beach to a pebble beach and evolves a darker, speckled coloration that closely resembles the pebble beach. This is an example of
directional selection
Imagine that a species of bird with an intermediate beak size becomes two separate species with large and small beaks. This is an example of
disruptive selection
In a certain species of salmon, some adult males are extremely large whereas other adult males are very small, compared to the females. There are no intermediate-sized adult males in the population. This is probably the result of
disruptive selection
Which of the following is an example of assortative mating?
female mouse chooses a mate because of same color
Shrews have been documented to travel across frozen lakes and establish populations on previously uninhabited islands. This is an example of
founder effect
The Pennsylvania Amish have a very high frequency of an unusual allele that results in short arms and legs and extra fingers. This high frequency is thought to be the result of
founder effect
From an evolutionary point of view, what important process occurs when a young male baboon leaves the troop that he was born in to join another troop?
gene flow
The net migration of alleles into or out of a population from neighboring populations is called
gene flow
Suppose a new mutation that improves metabolic efficiency is lost from a small population of mammals living in a region of seasonal food scarcity after a hurricane eliminates half the mammal population. This is an example of
genetic drift
The process by which allele frequencies are altered in a population due to chance is called
genetic drift
Which of the following can cause evolutionary change in a small population?
genetic drift
________ is due to chance events that change the allele frequencies in small populations.
genetic drift
having greater evolutionary fitness means:
having more offspring
Zoos often loan animals to other zoos for breeding purposes. From an evolutionary standpoint, what is the benefit?
increases genetic diversity
Which of the following can affect a small, endangered population so severely that it goes extinct?
lost alleles and/or low genetic diversity
Bright coloration in birds makes them stand out to predators. In female birds that sit on the nest, bright coloration is rare. This is likely the result of
natural selection
In the context of evolution, equilibrium means
no change in allele frequency
Within a large population, if no mutations occur, no migration occurs, all matings are random, and each individual has an equal chance of reproducing, which of the following will probably happen?
no evolution will occur
interaction of genes and environment produces a specific:
phenotype
Natural selection selects for or against certain
phenotypes
The extreme loss of genetic diversity that has occurred in cheetah populations due to overhunting is the result of
population bottleneck
Habitat loss, natural catastrophes, and/or excessive harvesting of a species often result in
population bottlenecks
Which of the following can evolve?
populations
A population carries two alleles for a trait in which T is dominant and t is recessive. In the Hardy-Weinberg equation, 2pq represents the
proportion of heterozygous individuals.
A population carries two alleles for a trait in which T is dominant and t is recessive. In the Hardy-Weinberg equation, p2 represents the
proportion of homozygous dominant individuals.
A population carries two alleles for a trait in which T is dominant and t is recessive. In the Hardy-Weinberg equation, q2 represents the
proportion of homozygous recessive individuals.
Mutations are important because they
provide variation that can result in evolutionary change.
allele frequency
relative proportion of a given allele in a population
The male peacock's beautiful tail is really a trade-off between
sexual & natural selection
Inbreeding is defined as
sexual reproduction among closely related individs
Female finches, which do not sing, tend to choose to mate with males that sing a specific, elaborate song. This is an example of
sexual selection
Imagine that a mutation for red eye color becomes very common in a population of flies because female flies in this population prefer to mate with red-eyed males. This is an example of
sexual selection
Male fish that display a bright blue color attract more mates as well as more predators. Maintaining that blue gene in the population is an example of
sexual selection
The bright coloration of male birds is often the result of
sexual selection
The elaborate courtship displays common among animals are the result of
sexual selection
The process by which allele frequencies are altered in a population to improve the odds of attracting a mate is called
sexual selection
Evolution by genetic drift is most obvious in
small populations
The type of selection most likely to act on a well-adapted population in a relatively constant environment is
stabilizing
When a species lives in a constant environment for a long time, the "average type" of individual may have the best chance of surviving and producing the most offspring. What type of selection is occurring?
stabilizing
If the tallest and shortest individuals of a population of humans do not survive and reproduce as well as the individuals of "average" height, which type of selection would most likely result?
stabilizing selection
In one butterfly species, the colors of individuals range from white to black, with many shades of gray in between. If the butterflies in a mountain population become more and more similar in color over several generations (for example, if most butterflies are the same shade of gray), what kind of evolutionary force is likely acting on the population?
stabilizing selection
Which of the following phenomena favors individuals with average phenotypes over those with extreme phenotypes?
stabilizing selection
Imagine that one of the original four mice that escape from a research lab is blind due to a genetic defect. If the escaped mouse breeds and most of the mice born in subsequent generations are blind from birth, this is most likely a case of
the founder effect
In general, each species of fruit fly in the Hawaiian archipelago is restricted to a single island. One hypothesis to explain this pattern is that new species formed after a small number of flies colonized each new island. This mechanism is called
the founder effect
Genetic drift results in a change in gene frequencies because
the population size is so small that chance occurrences can alter gene frequencies.