Practice Exam

In what way can natural selection produce new traits?

Natural selection cannot, by itself, produce new traits.

Can natural selection result in the evolution of phenotypes that decrease fitness?

No

What is likely to be different between these two human populations: population A, which has raised cows and eaten milk products for thousands of years, and population B, which has no history of raising cows or using milk?

The survival of individuals with alleles that promote the digestion of dairy products.

Are mutations good or bad?

They can be good, bad or neutral.

Traits evolve because they are needed for an individual to survive.

This statement is FALSE. Traits do not evolve because they are needed for an individual to survive; rather, traits evolve because they confer some sort of reproductive advantage that leads to increased fitness in a particular environment.

What is necessary for natural selection to occur?

Transmission of alleles from parents to offspring. Genetic variation. Differences among individuals in survival or reproduction.

Behaviors are impacted by differences in protein structure.

True

Behaviors can influence reproductive success. True or false?

True

Behaviors may be correlated with structural phenotypes (e.g. male-male fighting and large horns in male sheep). True or false?

True

Billions of genetic variations occur in our gametes.

True

Both the processes of natural selection and genetic drift result in evolution. True or false?

True

Chance determines which of a mother's alleles are present in a gamete but not how offspring with that allele survive in different environments after fertilization.

True

If resources like food and water are dispersed evenly throughout the habitat of an animal population, male phenotypes that attract females will likely be more important for fitness than male weapon phenotypes. True or false?

True

In larger populations, natural selection is generally stronger than genetic drift.

True

Independent assortment influences how those chromosomes get packaged into gametes.

True

Most gametes have different genetic combinations.

True

Most individuals have mutations.

True

Most mutations are due to errors in DNA replication that are not repaired. True or false?

True

Most new mutations in an individual will not be inherited by its offspring. True or false?

True

Mutations are the origin of all genetic variation in natural populations. True or false?

True

Mutations occur randomly.

True

Natural selection is non-random, and mutations are random. True or false?

True

Only natural selection results in adaptation.

True

Populations that are isolated from each other in different geographic locations will accumulate genetic differences due to new mutations.

True

Random allele frequency changes are expected to be larger in small populations than in large populations. True or false?

True

Recombination moves those mutations around to different copies of a chromosome, effectively reshuffling our genomes prior to making a gamete.

True

Speciation is typically a gradual process that involves divergence in many phenotypes. True or false?

True

The production of genetic variation, transmission of genetic variation, and sorting of genetic variation are required for speciation to occur.

True

Toxic chemicals are not a common cause of mutations in living organisms. True or false?

True

Variation in all of life is more than we typically think.

True

Mutations can be good, bad, or neutral.

True Environment dictates whether mutations are good, bad, or neutral.

Natural selection is considered a theory because it explains patterns of biological change. True or false?

True, theories explain.

Are mutations random?

Yes

What is mutation?

any change in the DNA sequence

Which of the following statements is FALSE about behaviors?

behaviors are not impacted by differences in protein structure

decreases genetic variation

both drift and selection

What is NOT necessary for natural selection to occur?

environmental change

morphologically different individuals found in the same environment should be classified as different species. true or false?

false

most individuals look the same because they are not genetically different from each other

false

scientists can predict which mutations will occur in which geographical areas

false

Which of the following is NOT a general pattern of variation in natural populations?

most variant phenotypes are harmful

A female sea turtle lays 100 eggs in a nest on a beach. 97 of the eggs successfully hatch. The other 3 fail to hatch and instead die because their genotypes caused errors in their development. This is an example of:

natural selection

What is sexual selection?

natural selection arising through preference by one sex for certain characteristics in individuals of the other sex

Is natural selection random?

no because the survival and reproductive success of an organism is related to the way its inherited traits function in its environment

Which of the following is required for natural selection to occur in a population? predators or other natural enemies, a large population, a harsh environment, a change in environment, or none of the these.

none of those

genetic drift is a _________ process

random

What is genetic drift?

random change in allele frequency

What is independent assortment?

random separation of homologous chromosomes

Fitness refers to the number of...

surviving offspring produced by an individual.

An allele that is present in 10% of individuals in a wild species of cat only affects male hair color and does not affect female hair color. Which of the following statements is TRUE?

the allele could be subject to natural selection

What is natural selection?

the process whereby organisms better adapted to their environment tend to survive and produce more offspring

What is genetic recombination?

the production of offspring with combinations of traits differing from either parent

large amounts of variation are inherited each generation

true

large amounts of variation are produced each generation

true

some variation is associated with environmental variables

true

The production of __________ is an essential part of natural selection and sexual selection.

variation

Which of the following are general patterns of variation in natural populations?

- all individuals are likely to carry new mutations - some variant types will be similar across different species - some variant types will likely occur more than once in the population

What is natural selection?

A process by which alleles increase or decrease in frequency in a population due to their impact on individual fitness.

Think about the examples of mouse fur color and elephant tusks. Which of the following factors do you think are MOST important to explaining BOTH phenomena? Choose the best option. - All populations had large amounts of heritable phenotypic variation as a result of mutations. - Coding and non-coding DNA tended to vary during stressful conditions (lack of food, habitat). - Because of the strong selective pressure from the environment, there was a lack of genetic drift occurring in these populations. - Organisms needed to adapt to different environments or they would die or go extinct. - The individuals in some populations gradually acclimated to the environment that they lived in.

All populations had large amounts of heritable phenotypic variation as a result of mutations.

Differences in survival and reproduction between the two populations are necessary for speciation to occur.

FALSE

Individuals within a species can evolve.

FALSE

Low fertility of hybrid offspring is an example of a pre-zygotic reproductive isolating mechanism.

FALSE

In humans, when all food types are abundant, including milk products, the frequency of high lactase activity alleles is expected to increase due to natural selection.

FALSE because natural selection is a gradual process that occurs over a long period of time. The presence of abundant food, including dairy products, may increase the overall consumption of lactose, but it does not necessarily lead to an increase in the frequency of lactase persistence alleles.

Both the processes of natural selection and drift involve the random survival of individuals or alleles. True or false?

False

Environmental conditions determine which mutations are most likely to occur. True or false?

False

Fitness refers to how long an individual organism lives. True or false?

False

If a population of animals shows a large difference in average body size between males and females, then body size has been affected by sexual selection, but not natural selection or genetic drift. True or false?

False

Male phenotypes that attract females are subject to sexual selection but not natural selection. True or false?

False

New mutant alleles that decrease the size of male weapons (e.g. horns) can increase in frequency only due to natural selection. True or false?

False

Phenotypes that males use as weapons are more likely to appear by mutation when resources are spread evenly across the environment than when they are clustered in the environment. True or false?

False

Populations that are geographically isolated from each other are expected to have the same new mutations, but selection will favor different ones.

False

Small populations that are isolated from each other in different geographic locations will accumulate differences due to genetic drift, but not natural selection. True or false?

False

The accumulation of genetic differences between isolated populations over time requires differences in the environment between the two populations. True or false?

False

Toxic chemicals are a common cause of mutations in living organisms. True or false?

False

Natural selection increases the likelihood of beneficial mutations arising in a population. True or false?

False Mutations are random.

The process of natural selection does not remove genetic variation from the population.

False Natural selection can remove certain alleles associated with lower fitness from a population, potentially reducing genetic variation. However, it can also maintain and promote diversity by favoring different alleles in different environments or times. New genetic variation can also arise through mutations and recombination, which provides the raw material for natural selection to act upon.

Both the processes of natural selection and genetic drift result in adaptation. True or false?

False Natural selection can result in adaptation, but genetic drift does not always do so.

Both the processes of natural selection and genetic drift require environmental change. True or false?

False Environmental change is not a necessary requirement for natural selection and genetic drift to occur. While they can be influenced by environmental factors, these processes can also occur due to other factors such as genetic mutations or chance events.

Natural selection is considered a theory because it describes patterns of biological change. True or false?

False, theories explain not describe.