MOSSES
Characteristics of Mosses
Moss come from phylum Bryophyta, they are characterized by their short flat leave and root-like rhizoids but really mosses don’t have true leaves, stems, or roots. Mosses result in a small shorter size because they lack vascular tissues, like xylem and phloem, which provides structural support and are needed for transporting water and nutrients. Mosses don’t have roots and stems to transport water, so they can dry out pretty quickly. Which is why they are found in moist environments, like shady grounds, tree trunks, rock, etc. The moisture is absorbed directly into the cells by osmosis. They are also considered as transitional plants between the aquatic and higher land plants. In an organism's life cycle, alternation of generation is a sexual and asexual phase. In the life cycle of a moss the gametophyte is the dominant generation. The gametophyte is a haploid generation, it only as a single set of chromosomes,a nd it produces gametes or sex cells. They are part of the sexual phase. The asexual phase is called the sporophyte generation. The sporophyte is a diploid, it has a double set of chromosomes and it produces spores asexually.
Labelled diagram of a moss
Calyptrs
-Protective hood that covers the capsule
Capsule
-Contains spores
Stalk/Seta
-Help raise the spores for more effective
dispersal
Sporophyte
-Diploid
-Grows out the gametophyte
-Has a capsule
Gametophyte
-Haploid
-Dominant Generation
-Goes through photosynthesis
Rhizoids
-Root-like structure
-Anchors the moss
Sample #1
Tortula Muralis
Common Name: Wall screw-moss
Found On: Tuesday, December 7th, 2021, 2:05 PM
Location: Sullivan Heights Secondary Highschool Laboratory
Observations and Description
- Shaped like a cushion
- Very fluffy and soft looking and green
- Has light green/yellow stalks all around it
- Tongue looking capsule
- 2cm in length (not including stalk and capsule) (My photo)
- 4cm in width (My photo)
- Can be found on concrete, cement, rocks, trees, and brick walls
Sample #2
Aulacomnium Palustre
Common Name: Ribbed Bog Moss Found On: Tuesday, December 7th, 2021, 2:04 PM
Location:Sullivan Heights Secondary Highschool Laboratory
Observation and Description
- Dark green
- Fuzzy looking
- Stems erect
- 5.5cm in length (My photo)
- Leaves lanced to egg shape
- sharp pointed
Sample 3/4
Light Green= Feather Moss
Also called: Plume Moss or Boreal Forest Moss
Found on: Wednesday, December 8th, 2021, 1:33 PM (Both pictures)
Location: OWL Park, 6116 146 St, Surrey, BC V3S 3A2
Observations and Description
- Formed on rotten wood
- Looks like a fern
- Fuzzy/soft looking
- light green
Dark Green= Thudium Delicatulum
Common name: Common Fern Moss
Found on: Wednesday, December 8, 2021, 1:33 PM (Both pictures)
Location: OWL Park, 6116 146 St, Surrey, BC V3S 3A2
Observations and Description
- Looks like a fern
- Rough looking
- Also prickly and scratchy looking
- Different sizes
- Dark green
Life cycle of mosses
Summarization of the life cycle of mosses
- The sperm from the antheridium swims to the eggs in the archegonium by water
- The eggs get fertilized
- The gametes fusion creates a zygote which is a diploid (2n) and will grow into a a sporophyte
- The developing sporophyte becomes a full grown moss with a capsule, stalk and gametophyte
- The capsule produces haploid (n) spores by meiosis
- When the conditions are favorable the operculum on the capsule opens and the spores are released and dispersed by wind and water
- When the spores land in moist habitat it will germinate into a protonema
- The protonema grows the gametophyte into the air and the rhizoids into the soil and develops into a moss
- The cycle repeats!!!
Adaptations mosses have made to live on land.
Mosses have made many adaptation that help them survive on land, they have increased their fitness in order for that to happen. Mosses don't have true leaves, stems, or roots but they have developed leaf, stem, root like structures for particular functions. Their leaf like structures are single cell layer thick they carry out photosynthesis, transforming sunlight into sugars the moss uses for food, the stem like structure hold the plant to the ground and the root like structure which is called rhizoids, helps the moss anchor itself to its substrates. Mosses suck up their nutrients through their rhizoids or draw in moisture or other minerals from their surrounding habitat. They also have a tall stalk, this helps them further spread their spores because, when the conditions are favorable the spores will be released from their capsule, the spores will be dispersed easily and further away. They have a thin cuticle, which helps prevent the moss from drying out.
Why do mosses need water?
Mosses require water for reproduction. Without water the sperm cannot swim to the eggs for fertilization. Mosses are unable to produce pollen tubes for fertilization like gymnosperms and angiosperms can. Mosses are also non-vascular, they do not have specific tissues that transports water and nutrients to the entire plant. This is called vascular tissue, without the vascular system they move water and nutrients over diffusion.
Why are mosses an evolutionary step?
Mosses are pretty close with aquatic plants. Mosses lack structural support, because they do not have true leaves, stems, or roots. So on land they are rather small and short. Aquatic plants also lack structural support but they stay tall because of the water. Initially aquatic plants already live in water so that water helps the sperm swim to the eggs, but for mosses it is harder, they need to be in a moist environment,because without water they will not be able to swim to the eggs. Aquatic plants also lack structural support but they stay tall because of the water. Both Mosses and aquatic plants are non-vascular they transport water and nutrients through diffusion
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