BIOL 226 Lecture Notes - Lecture 29: Charophyta, Gametangium, Sporopollenin
Document Summary
Age of multicellular life on land- 475 to 500 million years ago. Closest living relative of land plants-green algae, called charophytes (does not mean that plants are descended from them). Sporopollenin- layer of durable polymer that prevents exposed zygotes (charophyte) and gametophye (land plants) from drying out (desiccation- remove moisture). List and define the 5 derived characteristics that are common to all land plants: alternation of generations and multicellular, dependent embryos. Life cycle alternate between 2 generations: gametophytes and sporophytes. Includes both multicellular haploid organisms and multicellular diploid organisms. Embryos develop from zygotes that are retained within the tissures of the female parent (gametophyte) Parental tissues = provide the developing embryo with nutrients (sugars and amino acids). Embryo has specialized parental transfer cells: enhance the transfer of nutrients from parent to embryo: walled spores produced in sporangia. Spores are haploid reproductive cells that grow into multicellular haploid gametophytes by mitosis.
