Unit 4 – Notes #2 – Non-Vascular Terrestrial Plants
Kingdom: Plantae
Phyla: Bryophyta, Hepatophyta, and Anthocerotophyta
Members: Mosses, Liverworts and Hornworts
Typical Hornworts Liverworts
Moss (Hepatophyta) (Anthocerophyta)
(Bryophyta)
Characteristics of Bryophytes
Pigments:
1) Chlorophyll a 2) Chlorophyll b
-both are green pigments.
Habitat: 1) Can only thrive in wet areas (swamps, marshes, near streams)
2) Thrive in climates that receive year-round
precipitation; tropical and temperate rainforests.
A wet environment is crucial for bryophyte survival:
- As they lack a proper water transport system (non-vascular).
- No protective surface (waxy cuticle) to guard against water loss due to evaporation.
- Have flagellated sperm cells that must swim through water to fertilize eggs. Therefore; No water = No reproduction.
Morphology: (Form)
- Most look like miniature evergreen trees,
but only a few centimeters tall.
Moss Structure:
- Each moss plant has a thin upright
shoot that looks like a stem with tiny
leaves; these are not true leaves or
stems because they lack proper
transport tubules.
- From the base of the shoot grows a
number of thin branches called rhizoids
that penetrate into the ground and act
like roots to securely anchor the plant.
(they do not help in water transport)
- Water passes from cell to cell through
osmosis. This water transport system is fine if the organism is small. This is why bryophytes never grow tall.
Life Cycle:
- Life cycle involves the alternation between a haploid organism that gives rise to a diploid organism in the second generation, which gives rise to a third generation that is haploid and so on and so on….
- Have female and male gametophyte (1N) stage, this gametophyte stage produces haploid gametes (1N) from haploid plants. These gametes fuse to form a diploid (2N) zygote which gives rise to diploid sporophyte (2N) structures including a sporangium. Meiosis takes place in the sporangium to produce haploid (1N) spores to germinate into new gametophyte generation.
Moss Life Cycle: STUDY IT !