The Birth and Death of Genes: Quiz Results

1. Which of these characteristics affects the diffusion of oxygen into the icefish's blood?

  1. Icefish have scaleless skin.
  2. Icefish gills are white.
  3. Icefish have clear blood.
  4. Icefish hearts are colorless.

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2. Icefish live in very cold waters (-1.8 °C) where temperatures are below blood's freezing point. Which statements are true about icefish adaptations for cold water? (Note: More than one answer is correct.)

  1. Icefish lack hemoglobin, which prevents blood from freezing.
  2. Icefish lack red blood cells, which prevent blood from freezing.
  3. Icefish have antifreeze proteins, which prevent blood from freezing.
  4. Icefish lack red blood cells, which reduces the viscosity (thickness) of blood, allowing it to flow more freely at cold temperatures.

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3. Which statement is true of notothenioids?

  1. Notothenioids can live in very cold, nutrient-rich waters where other fish species cannot.
  2. All notothenioids lack functional globin genes. (Globin genes encode hemoglobin.)
  3. All notothenioids lack a functional antifreeze gene.
  4. All notothenioids have colorless blood.

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4. How did the icefish antifreeze gene arise?

  1. The antifreeze gene was caused by a single mutation.
  2. An existing gene was duplicated. It then acquired mutations, which caused it to have a different function.
  3. Cold Antarctic waters caused the mutation that created the antifreeze gene.
  4. The icefish antifreeze gene evolved before Antarctica broke away from South America.

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5. Which of the following statements about the "death" of the icefish globin gene are accurate?

  1. Natural selection in very cold waters caused the mutations that destroyed the globin gene.
  2. Loss of the icefish globin gene reduced the fitness of the icefish.
  3. Mutations destroyed the function of the icefish globin gene.
  4. Icefish DNA shows no trace of the globin gene.

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6. A strong selective pressure (like very cold water) can …

  1. … cause individuals with an advantageous mutation to have a reproductive advantage.
  2. … cause mutations.
  3. … cause individuals to evolve.
  4. … cause the environment to change.

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7. Compare the "birth" and "death" of icefish genes.

  1. The "birth" of the antifreeze gene and the "death" of the globin gene were both caused by duplication.
  2. Both the "birth" of the antifreeze gene and the "death" of the globin gene involved eliminating unnecessary genes.
  3. The "birth" of the antifreeze gene and the "death" of the globin gene are both examples of "inventing something new from something old."
  4. Both the "birth" of the antifreeze gene and the "death" of the globin gene were caused by mutation.

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