BIOL 2P93 Lecture Notes - Lecture 4: Karyogamy, Green Algae, Meiosis
22 Jan 2016
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Body plan: no specialization of algal body into root/stem. Photosynthetic portion = thallus + made up of hair-like rhizoids. Lack of an embryo: sperm + eggs fuse in open water, zygote develops into a new plant w/o protection. Other plant groups = zygote develops into embryo w/ protection of parent. Reproductive structures: gametes made w/in single cell + no protective jacket sterile cells. Table 15-1: green algae: rise evo developed plants + sister to land plants (order charales). 17,000 species, diverse structure, mostly aquatic, terrestrial (snow, tree trunks, soil, symbiotic w/ lichen), many microscopic, some bigger (codium magnum length 8m+, width 25cm). Green algae: morpho similarities btwn green algae + embryophytes (bryophytes + vc) = chlorophylls a + b; store starch (food reserve) inside plastids, firm cell walls of cellulose, hemicelluloses + pectic substances. Class was by appearance of their outer structure but now ultrastructural studies of mitosis, cytokinesis + reproductive cells = now several classes.
