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In areas where it rains often, mosses grow on roofs. How do mosses survive on roofs without soil?


Mosses absorb water and nutrients carried by the rain and do not need soil because they do not derive much nutrition from the soil.

What are the three classes of bryophytes?


The bryophytes are divided into three phyla: the liverworts or Hepaticophyta, the hornworts or Anthocerotophyta, and the mosses or true Bryophyta.

Describe two adaptations that are present in mosses, but not hornworts or liverworts, which reflect steps of evolution toward land plants.


Potential answers include:

  • Mosses exhibit a primitive conductive system in their stalks that transports nutrients and water.
  • Mosses exhibit a more complex, multicellular rhizoid system.

Bryophytes form a monophyletic group that transitions between green algae and vascular plants. Describe at least one similarity and one difference between bryophyte reproduction and green algae reproduction.


Similarities include:

  • Sexual reproduction is dependent upon water in which the male gamete swims.
  • The haploid organism is the dominant part of the life cycle.

Differences include:

  • Bryophyte gametotangia protect the gametes and the growing embryo.
  • Bryophytes make sporangium to produce spores.