HardBiologyHigh School (11–12)Diversity of Living Organisms › Plant Life Cycles and Alternation of GenerationsDiversity of Living Organisms › Gymnosperms and AngiospermsConceptual
In a moss, a fern and a pine, say which generation is the main plant, and whether the other…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
In a moss, a fern and a pine, say which generation is the main plant, and whether the other generation can live on its own. Then arrange the three plants by how small their gametophyte has become, from the largest to the smallest.
Need a reminder? The key ideaShow
The gametophyte () makes gametes; the sporophyte () makes spores by meiosis. Haplontic: the gametophyte is the main plant and the zygote is the only diploid cell (Spirogyra, Volvox). Diplontic: the sporophyte is the main plant (seed plants, Fucus). Haplo-diplontic: both are many-celled (bryophytes with the gametophyte main, pteridophytes with the sporophyte main).
The worked solution
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. Moss. The gametophyte is the main plant. The sporophyte depends on it and cannot live on its own.
Step 2. Fern. The sporophyte is the main plant. The gametophyte, the prothallus, is small but lives on its own.
Step 3. Pine. The sporophyte is the main plant. The gametophytes are reduced to the pollen grain and the female gametophyte inside the ovule, and they never live on their own.
Step 4. The order. The gametophyte shrinks from the moss to the fern to the pine.
Answer: moss: gametophyte main, sporophyte dependent; fern: sporophyte main, gametophyte independent but small; pine: sporophyte main, gametophytes inside the sporophyte. Gametophyte size: moss, then fern, then pine.
Discussion (0)
Log in to join the discussion.
Loading…