BIOL 112 Chapter Notes - Chapter 27: Lignin, Sorus, Paraphyly
Document Summary
Plant evolution: land plants evolved from an ancient aquatic green algae, similarities, multicellular, photosynthetic, same photosynthetic pigments (chlorophylls a and b, carotenoids, xanthophylls, cellulose cell walls, store excess carbohydrates as starch, plants evolved onto land ~445 mya. Gametangia and the embryo: gametangia, structures in which gametes are formed, antheridia (male, gametangia that produce sperm, archegonia (female, gametangia that produce eggs. The zygote develops into a multicellular embryo within the female gametangium, it"s a synapamorphy of land plans called embryophytes. Byrophytes (paraphyletic group: nonvascular (lack xylem and phloem, unlike other land plants, dominant gametophyte (haploid) generation, unlike other plants, sporophytes remain permanently attached, nutritionally dependent on gametophytes, no true roots, stems, or leaves (structures of dominant sporophytes) Club mosses: sporophytes have roots, stems and leaves, and strobili, microphylls: small leaves with a single vascular strand, strobili: cone-like clusters of reproductive leaves bearing sporangia. Includes horsetails: a group traditionally separate from ferns.
