Bio Ch 15- Mechanisms of evolution

Which of the following can evolve?

populations

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 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

When natural selection tends to split a population into two phenotypic groups, it is called

balanced polymorphism

multi-drug resistant bacteria

becoming more widespread

The 30,000 elephant seals alive today are genetically very similar due to

bottleneck effect

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 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

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

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

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 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.