Moss Life Cycle Diagram

Moss Life Cycle

• Mosses are non-vascular plants belonging to Phylum Bryophyta, living in moist environments.
• They have two life stages: haploid and diploid, both multicellular.
• Haploid has male and female plants, reproducing sexually, while diploid has only one sporangium, reproducing asexually.
• This change between haploid and diploid is known as the alternation of generations.
• Mature moss plants, or gametophytes, can be either male or female.

Gametophytes

• Mature females have archegonia, holding female gametes, reproductive organs, and the egg.
• Mature males have antheridia, holding male gametes, reproductive organs, and sperm.
• Gametophytes are part of the haploid life stage and occur at the top of the plant.

Sporophyte

• Sporophyte structure is responsible for asexual reproduction and the diploid part of the cycle.
• Sporophyte develops from a zygote, which undergoes mitosis, forming a sporangium.
• Inside the sporangium, meiosis takes place, producing four genetically diverse cells (spores).

Life Cycle Process

• The cycle starts with two separate gametophytes, male and female, sexually reproducing.
• Sperm meets an egg, resulting in a zygote, marking the beginning of the diploid phase.
• The zygote undergoes mitosis, forming a sporangium, which produces spores.
• Spores grow into new gametophytes, restarting the cycle.

Important Terms

• n: represents one set of chromosomes, often used to describe the haploid stage.
• 2n: represents two sets of chromosomes, often used to describe the diploid stage.
• Alternation of generations: the change between haploid and diploid stages in moss life cycle.
• Fusion: the process of sperm meeting an egg, resulting in a zygote.
• Meiosis: the process of producing genetically diverse cells (spores) in the sporophyte stage.

Moss Reproduction

• Moss reproduction involves two types: sexual and asexual.
• Sexual reproduction occurs in the gametophyte stage, involving male and female gametes.
• Asexual reproduction occurs in the sporophyte stage, involving only one plant.

Gametophyte vs Sporophyte

• Gametophyte: haploid, dominant, sexual reproduction, sperm and egg fusion.
• Sporophyte: diploid, recessive, asexual reproduction, meiosis and spore production.

Parts of Moss

• Antheridial head: holds the antheridium and eventually creates the sporangium.
• Antheridium: produces sperm.
• Archegonial head: produces eggs.
• Bud: small, germinated spores.
• Capsule: holds the spores.
• Calyptra: protection over a forming capsule.
• Early Embryo: pre-zygote cells, can be called germination or fusion.
• Egg/Archegonium: where fertilization takes place, the female gamete.
• Foot: helps to give nutrients to the sporophyte.
• Germinating spore: spores that have taken hold and will become new plants.
• Leaves: produce photosynthesis, collect water.
• Neck canal: route for sperm to travel for reproduction.
• Neck wall: creates the neck cavity.
• Operculum: breaks when spores are ready to leave and germinate.
• Protonema: hormones for new cellular growth.
• Rhizoids: specialized root-like structure, anchors the moss but does not absorb water like roots.
• Seta: helps transfer nutrients throughout the flower.
• Sperm/Antheridium: male gamete.
• Spores: type of reproduction from the sporophyte.
• Spore case: holds spores.
• Sporophyte: creates the spores.
• Venter: holds the egg.
• Venter wall: creates the venter cavity.
• Zygote: single-celled organism created after fusion of the egg and sperm.