BIOL 420 1st Edition Lecture 8Current LectureBiology 420Plant KingdomBryophytesPlant 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 (brings food);the tree rings = to old xylem(2) the diversification of vascular plants about 400 million years ago with spore (replaced seeds)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. 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 gametophyteThe Classification of Plants (Four major groups exist):Plant KingdomBryophytes and RelativesPteridophyta (Ferns) and RelativesGymnospermsand RelativesAngiosperms and RelativesExamples Mosses, liverworts, hornwortsFerns, Psilotum (whisk fern), Lycopodium, Equisetum (horsetails)Conifers, Gingko, cycadsFlowering plants, grasses, hardwoodsVascular tissue (xylem and phloem)Nonvascular Vascular Vascular VascularSporophyte/ GametophyteGametophyte (N) dominantSporophyte dominant, small separate GametophyteSporophyte dominantSporophyte dominantReproduction(spores or seeds)Spores Spores Seeds SeedsReproduction (Fertilization)Water Water Wind(Pollination)Wind/ animals (Flowers)Reproduction (Seed/spore dispersal)Water/ WindSporesWater/ WindSporesWindSeedsWind/animals(Fruits)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.SeedsBryophytesLecture 8Text Reference Chapter 16Bryophytes – mosses, liverworts, hornworts (wort – German word for plant)- Not radically different from the previous plants, haven’t really changed a lot - Small leafy plants- Nonvascular- Often moist environments, but widely distributed - Also found in wide range of habitats- Reproduce with spores – can be air-born, by water, by insects. Seeds: are cheap, light, prepackaged diploid that contains food – starch that can feed the embryo in the seed. There is a seed coat that protects it, dispersal that can go by the wind.Examples:- Tortula: found in central Mexico, found in deserts. - Campylopus: found in many places, but they found it growing in Antarctica. Found niches of volcano Bryophytes are transitional between green algae and vascular plants- Some green algae and plants are “paraphyletic” – they are part of groups that do notcontain all descendants of a common ancestorBryophytes and plants share a number of differences compared to algae:- Male and female gametangiaAntheridiaArchegonia- Retention of both zygotes and embryo within archegonium- Presence of multicellular, diploid sporophyte- Multicellular sporangium- Spores that resist decay and drying- Tissues produced from apical meristemsExample- Life cycle of a moss- Gametophyte stage- Sporophyte stage- Antheridia - Archegonia- Sporangium- Apical meristemsMoss –anatomy- Rhizoid- Leaflike body- Seta- CapsulePhylogeny of mosses, liverworts and hornworts- Liverworts – 450 mya- Mosses- HornwortsPhylum Marchantiophyta – liverworts- 5200 species- Liverwort name – doctrine of signaturesExamples- Marchantia- Life cycle- Antheridia- Archegonia- Gemmae cupsMosses: Phylum Bryophyta- The word “moss”- Examples of organisms that are not “true” mossesReindeer moss: ranges from tropical ages, more of a lichen than a mossClub moss: you would find this in the forest, vasucar plant, closer related to fernSpanish moss: a flowering plant, not a parasite, but photosynthesicIrish moss: red algae- Examples of mossesSphagnum- Peat moss: very important ecologically, important commercially as well. Can be burnedas a fuel, can be dry, can be used for mulch to enrich soil – sponge-like to absorb. Peatcan become coal, releases ton of carbon dioxide. o People Bogs: where people were found buried, in violently. These were somekind of virtual sacrifice; the acidity slows down the decomposition. Sticks andtransitions into something leather-like- Pseudopodium: - Operculum- Commercial and economic importanceGranite mossesDawsonia- Protonema: precursor of xylems. Having that vascular tissue would make it a large plant- Hydroids- LeptoidsPolytrichumMniumPhylum Anthocerotophyta–Hornworts- The horns are sporangium, shows some more advancements - Hornlike sporophyte- Thallus- Symbiotic with Nostoc- Some have symbiotic relationships with mycorrhizaExamples-