[Campbell Biology P.1102] The evolution of extraembryonic membranes, particularly the amnion,... | Practice Question

The evolution of extraembryonic membranes, particularly the amnion, was a crucial adaptation that enabled vertebrates to:

  • A: Develop a more efficient circulatory system.
  • B: Reproduce successfully in dry terrestrial environments.
  • C: Undergo metamorphosis during their life cycle.
  • D: Directly exchange nutrients with the mother's bloodstream.

Explanation

The text states that 'the extensive colonization of land by vertebrates was possible only after the evolution of structures that would allow reproduction in dry environments,' highlighting the shelled egg and uterus, both of which provide a fluid-filled sac via the amnion. This adaptation allowed embryos to develop in an aqueous environment despite being on land.