Bryophytes Lecture Notes

These flashcards cover key concepts related to bryophytes, including mosses, liverworts, their life cycles, importance in the ecosystem, and evolutionary traits.

What plants are included in the group Bryophytes?

Mosses and liverworts.

How do Bryophytes obtain water and nutrients?

Through diffusion, as they lack vascular tissue.

What is the defining feature of Bryophytes?

They do not have true stems, roots, or leaves.

What is the dominant generation in Bryophytes?

Haploid gametophytes.

What is a gametophyte?

The haploid stage in the plant life cycle that produces gametes.

What constitutes the sporophyte generation in Bryophytes?

The diploid structure that arises from the fertilization of gametes.

What are the three phyla representing Bryophytes today?

Bryophyta (mosses), Marchantiophyta (liverworts), and Anthocerophyta (hornworts).

What is the role of meiosis in the life cycle of mosses?

It produces haploid spores from the diploid sporangium.

What is Sphagnum commonly known as?

Peat moss.

Why are peatlands ecologically important?

They contain a significant amount of the world's soil carbon.

How do mosses contribute to soil nitrogen retention?

They help colonize bare, sandy soils and retain nitrogen.

What are rhizoids?

Root-like structures that anchor gametophytes but do not absorb water or minerals.

What type of fertilization occurs in mosses?

Water-mediated fertilization, where motile sperm swim to nonmotile eggs.

What is the function of archegonia in mosses?

They produce a single nonmotile egg.

How are moss spores produced?

By meiosis in the sporangium (capsule).

What happens to the sporangium when conditions are dry?

The peristome at the top disperses spores.

What is a protonema?

A mass of green, branched filaments formed from moss spores that absorb water and nutrients.

What is unique about hornwort sporophytes?

They are long, tapered, and grow up to 5 cm tall, releasing spores when they split.

Describe the appearance of liverwort gametophytes.

They are liver-shaped and may have elevated gametangia or stem-like structures.

How do the environmental conditions of peatlands affect decay?

Low temperature, pH, and oxygen levels inhibit decay.

What can happen if water levels in peatlands drop due to warming temperatures?

Decomposition may start to release more CO2, contributing to global warming.

What is the significance of Tollund Man?

A preserved corpse from a peat bog, dating from 405-100 BCE.

Why are gametophytes of Polytrichum spp. considered long-living?

They are dominant in the bryophyte life cycle.

What type of tissue is absent in Bryophytes?

Vascular tissue.

Which generation is usually less visible in mosses, gametophyte or sporophyte?

Sporophyte.

What ecological role do mosses play in wetland areas?

They act as a water retainer and help prevent soil erosion.

What happens to the color of sporophytes as they mature?

They turn from green (when young) to brown before releasing spores.

What do male gametangia (antheridia) produce?

Motile sperm.

What structures can female gametophytes produce multiple of?

Gametangia.

In Bryophytes, the diploid sporophyte generation is dependent on which generation?

The gametophyte generation.

What is the relationship between hornworts and nitrogen-fixing bacteria?

Clayhornworts form symbiotic relationships with them.

What percentage of Earth’s land surface is covered by peatlands?

3%.

What consequence does the overharvesting of Sphagnum have on the environment?

It releases stored CO2, contributing to global warming.