HABITAT & GENERAL CHARACTERISTICS
Where do mosses commonly grow?
Mosses commonly grow in moist and shady places.
What structures do mosses use to anchor themselves to a surface?
Rhizoids
Which life cycle stage is dominant in mosses?
The haploid gametophyte stage.
What structures produce sperm and eggs in mosses?
Antheridia produce sperm; archegonia produce eggs
What does poikilohydry mean in mosses?
Mosses’ internal water content changes to match their environment.
What type of plants are mosses based on their transport system?
Mosses are non-vascular plants.
Why do mosses not have true roots, stems, and leaves?
Because they are non-vascular plants (bryophytes) that lack the xylem and phloem tissue necessary to transport water and nutrients internally
What structure forms when a moss spore germinates?
A protonema
Why is water necessary for fertilization in mosses?
Sperm must swim through water to reach the egg
What happens to moss metabolism during extreme drying?
slows or stops until water is available again
Why are mosses usually found close to the ground?
They lack vascular tissues and lignin, so they cannot support tall growth.
What role do hydroids and leptoids play in some mosses?
They help transport water and sugars over short distances.
Where does meiosis occur in mosses?
In the capsule of the sporophyte.
What is the role of splash cups in some moss species?
They help disperse sperm using raindrops.
What is vitrification, and what molecules are involved?
Vitrification is the formation of a glass-like cytoplasm using sugars and LEA proteins during drying.
How does the absence of vascular tissue affect the way mosses obtain water and nutrients?
Mosses absorb water and nutrients across their surface and move them by diffusion and osmosis.
How do diffusion and osmosis function in moss transport systems?
Water and nutrients move across the surface and from cell to cell over short distances.
Why is the sporophyte nutritionally dependent on the gametophyte?
The sporophyte lacks sufficient photosynthetic ability and remains attached to the female gametophyte.
How do paraphyses contribute to moss reproduction?
They surround and protect the reproductive structures.
How do peristome teeth help improve spore dispersal?
They regulate spore release based on environmental conditions.
Explain how mosses show both adaptations to land and limitations compared to vascular plants.
Mosses have a cuticle and gametangia that protect against water loss and protect gametes, but lack lignin and vascular tissues, limiting size and complexity.
Explain why diffusion and osmosis limit the size and shape of moss plants.
These processes are only efficient over short distances, preventing mosses from growing tall or developing complex structures.
Explain how alternation of generations in mosses results in a dominant haploid stage.
Meiosis produces haploid spores that grow into gametophytes, while the diploid sporophyte is dependent and short-lived.
Explain how the structure of the archegonium increases reproductive success in mosses.
It protects the egg and developing zygote and ensures fertilization occurs in a moist, controlled environment.
Explain how pneumatic spore dispersal in Sphagnum allows spores to travel long distances.
Drying increases internal pressure until the capsule bursts open, releasing spores into air currents with high force.