Here's why:
* Before pollen: Early land plants, like mosses and ferns, needed water for sperm to swim to the egg for fertilization. This restricted them to moist environments.
* The rise of pollen: Pollen grains, which are essentially tiny, protected sperm cells, evolved. These grains could be transported by wind or insects, eliminating the need for water to carry the sperm.
* Seed plants: This major evolutionary advancement led to the development of seed plants (gymnosperms and angiosperms), which could reproduce in drier environments, allowing them to conquer terrestrial habitats.
So, pollen, and the subsequent evolution of seed plants, freed land plants from the constraints of water-dependent reproduction.
