BIOL 420 1st Edition Lecture 7Current LecturePlant Kingdom – Overview- Plants are multicellular, eukaryotic, autotrophic organisms.- Approximately 265,000 different types of plants exist today.- Plants began the transition to land about 425 million years ago. Plants play a critical roleas producers in the world's food webs; using photosynthesis to produce organic biomassand releasing oxygen as an end-product.- Plants are thought to have evolved from ancestors of the modern green algae.- Plant chloroplasts contain chlorophyll a, chlorophyll b, and a variety of yellow andorange carotenoids. Plant cell walls are composed of cellulose. Plants store carbohydrateas starch.- Nearly all plants reproduce sexually, though many also are capable of asexual modes ofreproduction.- Alternation of generation occurs in the life cycle of plants, with a haploid, gamete-producing gametophyte stage alternating with a diploid, spore-producing sporophytestage.- Bryophytes (true mosses) have a large, obvious gametophyte stage, but in other plantsthe sporophyte stage is larger and the gametophyte stage has been reduced. Non-vascular, many only grow only in the water because they need that to reproduce.- The evolution of plants is marked by four major adaptations:- (1) the evolution of vascular tissue – if you have xylem (brings water) and phloem(bringsfood); the tree rings = to old xylem- (2) the diversification of vascular plants about 400 million years ago with spore(replacedseeds) production as a means of reproduction- (3) the origin of seed producing plants about 360 million years ago and- (4) the evolution of flowering plants about 130 million years ago. These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Basic Vocabulary- vascular tissue - plant tissues that consist of cells that transport water and nutrientsthroughout the plant body. The two major types are xylem and phloem.- xylem - vascular tissue that carries water and minerals from the roots to the rest of theplant.- phloem - vascular tissue that carries sugar and organic nutrients (sap) throughout theplant.- gametangium - the gametophyte stage of mosses consisting of a maleantheridium and afemalearchegonium. Some are both sexes in one (monoscious)- gametophyte - multicellular, haploid stage of the life cycle that produces haploidgametes that fuse to form the diploid sporophyte- sporophyte - multicellular, diploid stage of the life cycle that through meiosis produceshaploid gametes that become the