Question 1

Which of the following best explains why the blood of Antarctic icefish appears colorless compared to most other vertebrates?

Accepted Answer

It lacks hemoglobin, the protein responsible for red coloration in blood.

Question 2

A researcher discovers a fish species in the Antarctic that survives in water temperatures below $$0^\circC. $$Which adaptation is most likely present in this species?

Accepted Answer

Production of antifreeze glycoproteins (AFGPs) to prevent ice crystal formation in bodily fluids.

Question 3

The absence of hemoglobin in icefish is an example of which evolutionary process?

Accepted Answer

Adaptive evolution in response to environmental pressures

Question 4

Which of the following best describes the function of antifreeze glycoproteins (AFGPs) in Antarctic fish?

Accepted Answer

They lower the freezing point of body fluids, preventing ice formation.

Question 5

A biologist studying the evolution of icefish notes that the myoglobin gene is nonfunctional in these species. What is the most likely consequence of this genetic change?

Accepted Answer

Reduced oxygen storage capacity in muscle tissue.

Question 6

Why are icefish able to survive without hemoglobin, unlike most other vertebrates?

Accepted Answer

They have a much lower metabolic rate and live in oxygen-rich cold waters.

Question 7

Which of the following best explains why the loss of hemoglobin in icefish did not result in their extinction?

Accepted Answer

The cold Antarctic waters hold more dissolved oxygen, compensating for the lack of hemoglobin.

Question 8

A mutation in the gene coding for AFGPs in Antarctic fish would most likely result in which of the following?

Accepted Answer

Greater susceptibility to ice crystal formation in body fluids.

Question 9

Which of the following statements about the evolution of icefish is supported by genetic evidence?

Accepted Answer

The loss of hemoglobin preceded the loss of myoglobin in evolutionary history.

Question 10

If a population of icefish were introduced to a warmer, less oxygen-rich environment, which of the following would most likely occur over several generations?

Accepted Answer

Selection would favor individuals with restored hemoglobin function.

Question 11

Which of the following best describes the role of the Antarctic Convergence in the evolution of icefish?

Accepted Answer

It created a physical barrier that isolated populations, promoting speciation.

Question 12

A scientist finds that the antifreeze glycoprotein gene in icefish is nearly identical to a trypsinogen gene. What does this suggest about the evolution of AFGPs?

Accepted Answer

AFGPs evolved from a duplication and modification of the trypsinogen gene.

Question 13

Which of the following is a direct consequence of the loss of myoglobin in icefish muscle tissue?

Accepted Answer

Decreased ability to store oxygen in muscle cells.

Question 14

Which of the following best explains why icefish have relatively large hearts and wide capillaries?

Accepted Answer

To compensate for the reduced oxygen-carrying capacity of their blood.

Question 15

Which of the following is NOT a likely reason why icefish can survive in the extreme cold of the Antarctic?

Accepted Answer

They have a high metabolic rate that generates internal heat.

Question 16

Which University of Maine researcher is known for studies on the myoglobin gene of icefish?

Accepted Answer

Bruce Sidell

Question 17

Which of the following best describes the environment where icefish are 'ill-suited' to survive?

Accepted Answer

Warm waters

Question 18

Which of the following statements about the evolutionary history of icefish is supported by fossil and genetic evidence?

Accepted Answer

Icefish evolved after Antarctica became fully surrounded by water, leading to the formation of the Antarctic Convergence.

Adaptations and Biology of Antarctic Icefish: Study Guide

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