[Campbell Biology P.1069] Consider the sex reversal patterns in bluehead wrasse and oysters a... | Practice Question

Consider the sex reversal patterns in bluehead wrasse and oysters as described in the text. Which of the following best explains the adaptive significance of these patterns?

  • A: Both species switch sexes to ensure higher overall gamete production, as larger individuals consistently produce more eggs.
  • B: Bluehead wrasse females transform into males to maximize sperm production, while oysters transform from males to females to maximize egg production.
  • C: Bluehead wrasse females become males to defend the harem more effectively, whereas oysters, being sedentary, switch from male to female at larger sizes to release more gametes into the water.
  • D: Sex reversal in both species is primarily a response to low population density, allowing individuals to reproduce without a partner.

Explanation

The bluehead wrasse undergoes sex reversal from female to male, with the largest female transforming into a male to take over the harem defense, as larger males are more effective. Oysters undergo sex reversal from male to female when they reach their largest size, as larger females can produce significantly more gametes, maximizing reproductive success, especially as they are sedentary and release gametes into water.