Q: A population of beetles has two alleles for a gene: A and a. If the frequency of allele A is 0.7 and allele a is 0.3, what is the expected frequency of heterozygotes (Aa) under Hardy-Weinberg equilibrium? Use the equation $$2pq.$$

$$2pq = 2 \times 0.7 \times 0.3 = 0.42$$

Question 1

Which of the following best describes the Central Dogma of Molecular Biology?

Accepted Answer

DNA is transcribed into RNA, which is then translated into protein.

Question 2

A population of beetles has two alleles for a gene: A and a. If the frequency of allele A is 0.7 and allele a is 0.3, what is the expected frequency of heterozygotes (Aa) under Hardy-Weinberg equilibrium? Use the equation $$2pq.$$

Accepted Answer

$$2pq = 2 	imes 0.7 	imes 0.3 = 0.42$$

Question 3

Which of the following scenarios best illustrates disruptive selection?

Accepted Answer

A population of birds where both very large and very small beak sizes are favored, while medium beak sizes are selected against.

Question 4

Which process is primarily responsible for the oxygenation of Earth's atmosphere?

Accepted Answer

Oxygenic photosynthesis

Question 5

A researcher observes that a certain trait in a population is controlled by many genes, each contributing a small effect, resulting in a continuous range of phenotypes. This trait is best described as:

Accepted Answer

A continuous (polygenic) trait

Question 6

Which of the following best explains why genetic drift has a stronger effect in small populations?

Accepted Answer

Random changes in allele frequencies are more likely to lead to fixation or loss of alleles in small populations.

Question 7

Which of the following is an example of allopatric differentiation by vicariance?

Accepted Answer

A river forms and splits a population of mice into two isolated groups.

Question 8

Which of the following best describes the difference between absolute fitness and relative fitness?

Accepted Answer

Absolute fitness is the total number of offspring produced, while relative fitness compares an individual's reproductive success to others in the population.

Question 9

Which of the following is a direct effect of increased atmospheric CO$$_2 on $$ocean ecosystems?

Accepted Answer

Ocean acidification

Question 10

A population of frogs has a net reproductive rate $$R = 1.2. $$What does this indicate about the population's growth?

Accepted Answer

The population is increasing in size.

Question 11

Which of the following best describes the role of a keystone species in a community?

Accepted Answer

It has a disproportionately large effect on community structure relative to its abundance.

Question 12

Which of the following equations correctly represents exponential population growth?

Accepted Answer

$$\frac{dN}{dt} = rN$$

Question 13

Which of the following is an example of reciprocal altruism?

Accepted Answer

A vampire bat shares blood with another bat, expecting the favor to be returned in the future.

Question 14

Which of the following best describes the difference between a fundamental niche and a realized niche?

Accepted Answer

A fundamental niche is the full range of environmental conditions a species can occupy, while a realized niche is where it actually exists due to biotic interactions.

Question 15

Which of the following best explains why homeotherms generally have lower trophic efficiency than poikilotherms?

Accepted Answer

Homeotherms use more energy to maintain a constant body temperature, reducing the energy available for growth and reproduction.

Question 16

Which of the following is a direct result of stabilizing selection in a population?

Accepted Answer

Individuals with intermediate phenotypes increase in frequency.

Question 17

Which of the following best describes the process of secondary ecological succession?

Accepted Answer

It occurs in an area where a disturbance has destroyed a community but left the soil intact.

Question 18

Which of the following is a key difference between prokaryotes and eukaryotes?

Accepted Answer

Eukaryotes have membrane-bound organelles, while prokaryotes do not.

Question 19

Which of the following best describes the effect of gene flow on genetic variation between populations?

Accepted Answer

Gene flow tends to reduce genetic differences between populations.

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