EEB268H1 Lecture 7: Lecture 7 - Gymsnosperms
25 Dec 2015
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Lecture 7 ecology and diversity of naked seed plants. Grouped 4 major groups (phylum names): cycadophyta, ginkophyta (1 sp. , coniferophyta (fir, spruce, pinus, gnetophyta (living fossils, tracheids = simpler form, vessel elements = more advanced form. Conducting elements exist in xylem to move water from roots to leaves. Motile sperm: common in mosses/algae, only in some gymnosperms (cycads and gingkos) In gnetophytes and conifers have sperm tube so don"t need motile sperm. But when reproduces forms cones w/ seeds on them. Cycads common in tropical/subtropical places/warm temperate zones. Gingko biloba a living fossil (slide 5) Relic species from china preserved in cultivation. Can see gingko seed: seed not fruit even though it is fleshy. October 28th, 2015: = megasporangium megaspore megagametophyte archegonia egg. Parent (seed coat/integument) o: megagametophyte (nutrient tissue) o, pollen tube lands within nucellus (megagametophyte) Sperm released at periphery of egg (not right at egg) so still have to swim up to egg.
