Alternation of generations Haploid (n) stage that produces gametes followed by diploid (2n) stage producing spores Gametophyte (haploid) that produces gametes. Gametes fuse to form zygotes that develop into sporophytes Sporophytes (diploid) that produce spores. Spores are haploid cells that can develop into a new organism without fusing with another cell.
Homosporous and Heterosporous Homosporous One spore type produced and released Heterosporous Two spore types produced one developing into a male gametophyte, the other into a female gametophyte
Only one size of spore is produced The spore germinates into a bisexual gametophyte. The gametophyte releases the sex cells, or gametes,then fertilize and produce a zygote. The zygote, over time, then develops into a sporophyte, the plant.
Two sizes of spores are produced. The spore germinates into a gametophyte. The gametophyte will then produce megaspores(egg) and microspores(sperm). After receiving water, the sperm will swim out of the microsprorangium and go inside the megasporangium, where it will fertilize the egg. After many years, the sporophyte will grow out of the megasporangium or microsporangium
Dominant generation In alternation of generations, the dominant generation is the generation that occupies the largest portion of the life cycle.
Bryophytes No vascular tissues Live in damp/moist environments and are small Gametophyte is the dominant generation in the life cycles of bryophytes Root Absent Rhizoid (root like structure)
Gametophyte of a moss is dominance Largest and longest lived generation Green moss gametophyte produces gametangia Function : Produce gametes Male (antheridia-produce sperm) Female (archegonia-produce egg) Gamete protect by jacket of sterile cell- protect from drying and dying
Sporophytes Smaller than gametophytes Attach to gametophytes Lack of chlorophyll depend
Matured sporophyte, spore mother cells undergoes meiosis to form haploid spores Spores begin gametophyte generation Spore mature capsule open spore carry of by wind germinate protonema bud gametophyte
Asexual Reproduction Fragmentation Small pieces broken from gametophyte, grow into new plant Gemmae Tiny pieces of tissues from new gametophyte When raindrop splash,gemmae germinate to gametophyte