Q: A population of flowers has two alleles for color: red (R) and white (r). If the frequency of R is 0.7 and r is 0.3, what is the expected frequency of heterozygotes under Hardy-Weinberg equilibrium?

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

Question 1

Which of the following best explains why food chains in most ecosystems rarely exceed four or five trophic levels?

Accepted Answer

Only about 10% of energy is transferred to the next trophic level, with the rest lost as heat and waste.

Question 2

A population of beetles is separated by a river, preventing gene flow between the two groups. Over time, the two populations evolve independently and can no longer interbreed. What evolutionary process does this scenario illustrate?

Accepted Answer

Allopatric speciation

Question 3

Which of the following is an example of codominance in humans?

Accepted Answer

A person with type AB blood expressing both A and B antigens equally

Question 4

Which of the following best describes the role of decomposers in an ecosystem?

Accepted Answer

They recycle nutrients by breaking down dead organic matter, returning elements to the soil.

Question 5

A mutation causes a single nucleotide to be removed from a gene sequence, shifting the reading frame. What type of mutation is this, and what is a likely consequence?

Accepted Answer

Frameshift; results in a completely altered protein downstream

Question 6

Which process is responsible for the rapid diversification of a single ancestral species into multiple species, each adapted to a different ecological niche?

Accepted Answer

Adaptive radiation

Question 7

In the context of the carbon cycle, which process removes carbon dioxide from the atmosphere and incorporates it into organic molecules?

Accepted Answer

Photosynthesis

Question 8

Which of the following equations represents the Hardy-Weinberg equilibrium for a gene with two alleles?

Accepted Answer

$$P^2 + 2PQ$$ + $$Q^2 = 1$

Question 9

Which of the following is a prezygotic barrier that prevents fertilization between species due to differences in mating rituals?

Accepted Answer

Behavioral isolation

Question 10

Which of the following best describes the function of the lac operon in E. coli?

Accepted Answer

It is an inducible operon that allows gene transcription only when lactose is present.

Question 11

Which of the following is a direct consequence of the Law of Conservation of Matter in cellular respiration?

Accepted Answer

Atoms from glucose and oxygen are rearranged to form carbon dioxide and water.

Question 12

Which of the following best illustrates convergent evolution?

Accepted Answer

Wings of bats and wings of birds, which evolved independently for flight

Question 13

A population of flowers has two alleles for color: red (R) and white (r). If the frequency of R is 0.7 and r is 0.3, what is the expected frequency of heterozygotes under Hardy-Weinberg equilibrium?

Accepted Answer

$$2 	imes 0.7 	imes 0.3 = 0.42$$

Question 14

Which of the following is an example of a frameshift mutation?

Accepted Answer

A nucleotide is inserted, shifting the reading frame

Question 15

Which of the following best describes the role of alternate splicing in gene expression?

Accepted Answer

It allows a single gene to produce multiple protein variants by joining different combinations of exons.

Question 16

Which of the following is a real-world example of the bottleneck effect?

Accepted Answer

A population of cheetahs with very low genetic diversity due to a past drastic reduction in numbers

Question 17

Which of the following best describes the function of DNA bending proteins?

Accepted Answer

They physically alter the shape of DNA to regulate gene expression.

Question 18

Which of the following is an example of mutualism?

Accepted Answer

Bees pollinating flowers while obtaining nectar

Question 19

Which of the following best explains why genetic variation is important for natural selection?

Accepted Answer

It provides the raw material for populations to adapt to changing environments.

Core Concepts in Ecosystem Dynamics, Evolution, and Molecular Biology

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