BIO 200 Lecture Notes - Lecture 15: Welwitschia, Sequoia Sempervirens, Drupe

• School: University at Buffalo
• Department: Biological Sciences
• Course: BIO 200
• Professor: jessicapoulin

Document Summary

Plant embryo -> seed -> 2 tissue layers (integument: seed coat, mega sporangium: edible part) > embryo disperse -> internal food source -> 2nd grade adaptation: dormancy (between dispersal and sprouting) -> allows seed to choose when to sprout -> spreads and successes seed bearing plants. Divide into male/female a bit earlier -> 2 parts before eggs and sperm. 2n zygote -> whole seed disperses -> lucky -> germinate and grow into a mature sporophytic plant. Important facts: seeds -> dispersal, seeds -> dormancy, heterozygous, sporophytic, evolution of seeds, pollen, pollen tube -> dispense for the need for water -> live in wider variety of environments. Naked seed (no sporophytic tissue majority of life) 4 extant groups: cycads gingkos, gnetophytes, conifers: cycads: ancient. Motile sperm: gingkos: 1 species extant = gingko biloba. Dioecious (male and female separate parts) -> males: cones -> females: lost cones (fruit-like: bad smell: gnetophytes: trachea cells.