[Campbell Biology P.687] The evolution of pollen in seed plants represents a significant ada... | Practice Question

The evolution of pollen in seed plants represents a significant adaptation that distinguishes them from nonvascular and seedless vascular plants. Which of the following is an accurate advantage conferred by pollen?

  • A: Pollen allowed seed plants to retain their reliance on water for sperm dispersal, promoting aquatic colonization.
  • B: Sporopollenin within the pollen wall provides protection, enabling transport by wind or animals to dry habitats.
  • C: Pollen grains are flagellated and actively swim to the egg, increasing fertilization efficiency.
  • D: The development of a pollen tube eliminated the need for male gametophytes, simplifying the life cycle.

Explanation

Sporopollenin in the pollen wall is a key adaptation, protecting the pollen grain during transport by wind or animals, which allows seed plants to colonize dry terrestrial habitats. The pollen tube then delivers sperm directly to the egg, removing the dependence on a water film for fertilization.