Question

1. gene flow happens when:

a. mutations occur
b. organisms move between populations
c. populations shrink
d. random mating stops

1. gene flow usually:

a. decreases variation within populations
b. increases variation within populations
c. stops evolution
d. causes extinction

1. nonrandom mating often results in:

a. more heterozygous individuals
b. increased mutations
c. inbreeding
d. no evolution

1. a mutation is best described as:

a. a planned genetic change
b. a random change in genetic material
c. migration of organisms
d. a mating pattern

1. most mutations are:

a. helpful
b. neutral
c. harmful
d. required for survival

1. which type of selection favors the average trait?

a. directional selection
b. disruptive selection
c. stabilizing selection
d. sexual selection

Explanation:

1. Gene flow is defined as the transfer of genetic material between populations, which occurs when organisms move between them.
2. By introducing new genetic material from other populations, gene flow adds genetic diversity, increasing variation within a population.
3. Nonrandom mating includes mating between closely related individuals, which is inbreeding; it leads to more homozygous, not heterozygous, individuals, does not increase mutations, and can drive evolution.
4. Mutations are unplanned, random alterations in an organism's DNA (genetic material), unrelated to migration or mating patterns.
5. Most mutations have no significant effect on an organism's fitness, meaning they are neutral; beneficial and harmful mutations are less common.
6. Stabilizing selection eliminates extreme trait variations, favoring the average, most common trait in a population.

Answer:

1. B. Organisms move between populations
2. B. Increases variation within populations
3. C. Inbreeding
4. B. A random change in genetic material
5. B. Neutral
6. C. Stabilizing selection