Genetics and Evolution Quiz

A species of tree called Silver Maple has leaf shape controlled by gene L, where lobed leaves (L) are dominant over unlobed leaves (l). In 2005, researchers examined a large population of Silver Maples in a forest in Wisconsin, collecting DNA samples from 400 trees. They found:

• 120 LL trees (homozygous dominant)

• 200 Ll trees (heterozygous)

• 80 ll trees (homozygous recessive)

From this, the population had allele frequencies of 0.40 for L and 0.60 for l

In 2023, researchers returned to resample this population and found:

• 50 LL trees

• 150 Ll trees

• 200 ll trees

The allele frequencies calculated from this sample were 0.25 for L and 0.75 for l.

What mechanism is most likely the primary cause of the change of allele frequencies in this population?

• Natural selection

• Gene Flow

• Genetic Drift

• Mutations

When two heterozygous Maple Trees (Llx Ll) in the population produce offspring, they have 21 lobed leaves and 3 unlobed leaves (l). This mating would contribute to (blank) in this population because (blank).

• Genetic Drift: the offspring produced by this cross vary from the expected phenotypic ratio

• Genetic Drift: the offspring produced follow expected mendelian ratios.

• Natural Selection: the plants produce more lobed leaves offspring than expected.

• Natural Selection: there is a higher fitness for those who have lobed leaves.

Evolution is defined as:

• Breaking Hardy- Weinberg

• Changing genotype frequencies over time

• Changing allele frequencies over time

• Only natural selection occurring

Which of the following increases genetic variation in a population?(Select all that apply)

• Gene flow

• Natural Selection

• Mutations

• Stabilizing Selection

• Genetic Drift

Which of the following statements is TRUE about Hardy-Weinberg Equilibrium? (Select all that apply)

• When genotype frequencies change in a population over time, the population remains in hardy-weinberg equilibrium as long as allele frequencies don’t change

• Hardy- Weinberg represents evolution not occurring in a population

• Meeting Hardy-Weinberg expectation is very rare

• Individuals in a population must show non-random mating for that population to remain in Hardy-Weinberg equilibrium.

• Hardy-Weinberg equilibrium is more likely to occur within LARGE populations.

If I tell you that a Siberian Tiger has a greater evolutionary fitness than another Siberian tiger in the same population what does that mean?

A severe drought drastically reduced a population of western tiger salamanders, wiping out 95% of the individuals. The few surviving salamanders exhibited a strikingly brighter coloration on average compared to the original population. What process most kiley led to the brighter coloration of the western tiger salamanders?

• Directional selection

• Stabilizing selection

• Genetic Drift b/c of bottleneck effect

• Mutations

In a population of 1000 dragonfly, 80% alleles are dominant. What is the frequency of recessive allele?

• 0.8

• 0.2

• 20%

• 80%