BIO 102 Lecture Notes - Lecture 7: Pollen Tube, Gymnosperm, Ginkgo Biloba
Document Summary
Algae, through dna comparisons, are plants closest living relatives. Key features: 1) multicellular, 2) ability to photosynthesize, and 3) variety in generations. Diploid plant produces haploid spores through meiosis. given by parent plant. Provide shelter; wood for housing, fuel (wood, coal, remains of ancient plants), medicine (drugs), and pleasure (tea, wine, flowers. ) Certain anatomical structures have been milestones in evolution. chlorophyll and pigments. Had to evolve to adapt to fresh water habitats. Land adaptations: roots- anchor plants waxy cuticle- reduces water loss stomata- allows gas exchange conducting vesicles- transportation of water and nutrients lignin- stiffening agent in cell walls, supports plant. Pollen allows wind, instead of water, to carry sperm. Byrophytes: (non-vascular plants) lack well developed structures for carrying nutrients and water. Sporophyte remains attached and is nutritionally dependent on gametophyte. Sperm swim to egg spores disperse > cycle repeats. May be in same plant, but don"t have to. Fertilization: diploid sporophyte > produces spores through meiosis > haploid.
