Types

• Two major groups of plant life continue to reproduce with spores. The bryophytes, a primitive group of plants that includes mosses and liverworts, use spores. Although ferns evolved into seed producers late in their evolutionary history, all extant examples today reproduce with spores.
  
  

History

• Bryophytes and ferns are among the oldest plants on Earth. The earliest plants evolved from aquatic algae, and their life functions -- including reproduction -- were best adapted to an aquatic environment. Spore production in bryophytes and ferns requires moisture to allow the swimming sperm to move to the egg cell.
  
  

Significance

• Spore-producing plants, therefore, require high levels of moisture in order to survive. The development of the seed shifted plants to reproductive strategies that used wind and pollinators to carry sperm cells to female plant structures. This removed plants from water-dependent reproduction with spores and allowed them to colonize increasingly dry habitats.