Unit 7 Test Review

Which of the following BEST describes natural selection?

• Traits that are genetically dominant will always show up no matter what the environment is like.

• Those traits that best help an organism survive in its environment will more likely be passed on than those that don’t.

• Which traits get passed on is completely random and all traits have an equal chance for survival regardless of the environment.

• Traits for organisms can be manipulated and selected by humans by breeding those organisms with desired traits together.

If an organism has the best adaptation for an environment, what tends to happen?

• The will leave more offspring that are less suited for that environment.

• They will decrease in population size over many generations.

• They will leave more offspring that are better suited for the environment.

• They will not be able to out-compete other organisms for resources.

Based on the figure, which organism is most closely related to the polar bear?

• Black Bear

• European Brown Bear

• Western North American Brown Bear

• Asian Brown Bear

If the frequency of dominant phenotype is 0.36, what is the frequency of the dominant allele?

• 0.2

• 0.48

• 0.6

• 0.8

What does p stand for?

• Dominant allele

• Recessive allele

• Homozygous dominant

• Homozygous recessive

• Heterozygous

If there are 400 red flowers, 200 pink flowers, and 100 white flowers. Solve for the frequency of the recessive allele.

• 0.28

• 0.14

• 0.38

• 0.42

What factors would increase the frequency of a genotype in a population over time?

• Increased reproduction rates in a population

• Selective pressures that make the trait favorable

• Genetic drift

• Mutations in the population

Why would the presence of a particular genotype or phenotype decrease in a population over time?

• Due to increased competition

• Reproductive isolation

• Changes in the environment that now make the trait less favorable

• Gene flow

What is artificial selection?

• When humans selectively breed organisms together to select for traits most desirable to us

• When a new species has formed

• When new organisms migrate into an area and introduce new genes

• When organisms are separated from other members of their population due to new geographic barriers

What is the founder effect?

• When survivors of a natural disaster repopulate the environment

• When a small population breaks off of an existing population

• Changes in the genetic makeup of a population over time

• The migration of organisms between two similar populations