BIOL165 Lecture Notes - Lecture 11: Achene, Dioecy, Mitosis
4 Feb 2017
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Dominant phase is the haploid gametophyte (gametothallus stage) 2n zygote the only cell of the sporothallus stage. Sexual reproduction: haploid outer cells going to form the gametes. Immotile egg cell will form, in another pocket sperm is formed, will e(cid:448)e(cid:374)tually lea(cid:448)e the i(cid:374)(cid:448)agi(cid:374)atio(cid:374) a(cid:374)d s(cid:449)i(cid:373) off i(cid:374)to the egg"s i(cid:374)(cid:448)agi(cid:374)atio(cid:374) Will settle out into sediment and an environmental stimuli told colony to make these resting stages. The diploid zygote (sporophyte) will fall, land in sediment until conditions are good once again, when spring occurs, will carry out meiosis to form meiospores and start process again. Class ulvophyceae: mostly macroscopic marine algae, uninucleate and siphonous-multinucleate forms, life cycle of sea lettuce. Carry different complements of their genome but look exactly the same. No true dominant stage because all look same. Gametophytes and sporophytes look the same unless actively producing gametes or spores.
