22.1 Mosses22.2 Liverworts and Hornworts22.3 Seedless Vascular Plants22.1 MossesChapter 22: Seedless PlantsObjectives22.1 Mosses- Identify some characteristics of mosses.- Describe the life cycle of mosses22.2 Liverworts and Hornworts- Discuss the characteristics of liverworts and hornworts- Compare and contrast liverworts, hornworts and mosses22.3 Seedless Vascular Plants- Describe the characteristics of seedless vascular plants- Compare whisk ferns, club mosses, and horsetails.22.4 Ferns- Describe the characteristics of ferns- Explain the life cycle of a fern122.1 MossesSimilar to first land plantsNonvascular plant belonging to class Musci and division Bryophyta14,000 species- more than any other bryophytemost are tropicalsome can survive dry climatesall need water to complete their life cyclecommon characteristics include:photosyntheticmulticellularsexually reproducingeukaryoticnon-complicated vascular system- water moves cell to cell by osmosis since most mosses are only a few cells thicklive on moist brick walls, cracks of sidewalks, forest floors, shady sides of treesThe Life Cycle of MossesTypical moss alternates between haploid gametophyte (N) and diploid sporophyte stages (2N)Gametophyte stage-Small gametophyte is longest lived part of the life cycleLeaf like photosynthetic structures lack vascular tissue and are usually only one cell thickHave rhizoids on underside to anchor moss Sporophyte stage- usually smaller and attached to the gametophyte Lacks chlorophyll depending on gametophyte for foodFoot of gametophyte anchors it to sporophyte 2Stalk grows up and is topped by a capsuleCapsule (sporangium) is the structure that forms haploid sporesSexual ReproductionProduce two kinds of gametes: egg & spermGametes surrounded by sterile cells that protect them from drying outEggs are large w/ much cytoplasm and immobileSperm are smaller, flagellated and must swim through water to fertilize the eggArchegonium- the egg producing structure of a mossFlask shaped3Forms on branches of gametophyteEach archegonium forms one eggAntheridium- sperm producing structure of a mossPart of the gametophyteSpherical or sausage shapedEach Antheridium produces many spermBecause the sperm must swim from antheridium to archegonium reproduction can only take place when the gametophyte is under waterSperm follow a trail of chemicals released by the egg in the waterAfter fertilization a zygote is formed which undergoes mitosis to become a sporophyteAfter maturation the sporophyte forms haploid spores to begin the gametophyte generationWhen spores are mature the capsule opens and the wind carries off the spores; if it lands in a moist place it sprouts to form a new gametophyteAsexual ReproductionCan occur in two ways:Fragmentation- small pieces are broken off and form a new plantGemmae- (= swelling or bud. Latin) tiny pieces of tissue that can form new gametophytes. Raindrops splash the gemmae off the parent plant and they are carried away to a new area to form new gametophytesMosses and the Ecosystemdecomposerspioneer specieskeep soil moist and prevent soil erosionshelter for insects and animalsnesting materials for birds & mammalsPeat bogs- a wet ecosystem that is formed by large mats of sphagnum (peat moss)4Sphagnum release a chemical that prevents decomposers from growing; this means that the sphagnum decomposes very slowly and will build up eventually turning a pomd into marshy soilUses of peat moss include:- Burnable fuel- Extremely absorbent making it an excellent additive for dry sandy soil- Moist protective cushion for shipping of plants- Used in diapers & bandaids22.2 Liverworts and HornwortsBoth nonvascularBoth alternate between diploid sporophyte generation and haploid gametophyte generationGametophytes are green a leafy producing archegonia and antheridiaSporophytes attached to gametophytesNeed lots of water for fertilizationLiverworts- about 7000 speciesLiver like shape- thought to cure liver diseases in medieval times (called Doctrine of Signatures)5Umbrella shaped structures are antheridia and archegonia are attached to leafy gametophyte producing gametesAsexual reproduction Gametophytes have growing tips that split into branches as it grows along the ground. When older parts die the newer branches live on as independent plantsGemmae are also produced in gemmae cups on upper surface of gametophyte. Rain splashes the gemmae out of the cup. If it washes to a proper location it starts a new gametophyte6Hornworts- about 100 speciesArchegonia and antheridia form inside the plantA cyanobacteria, Nostoc, sometimes lives in cavities in the gametophytePost fertilization zygotes become long horn like sporophytesThese sporophytes are photosynthetic and therefore not totally dependent on the gametophytes→ 6CO2 + 6H2O + Light Energy→ C6H12O6 + 6O2Spores are spread by drying and splitting of the long thin sporangiaNot as closely related as mosses and liverworts 22.3 Seedless Vascular PlantsVascular Plants/Seedless Plants- Vascular tissue allows them live in areas that bryophytes cannot giving them advantages in the competition for light and water- Gametophytes tend to be smaller than the sporophytes- Gametophytes are separate and independent from sporophyteWhisk ferns- (10-13 species) are tropical plants with simple water-carrying tissues. Some areleaflessOne genera grows in Texas, Florida, Louisiana, Arizona, and HawaiiThe other genera grows on islands of the South Pacific Ocean One species resembles straws in a whisk broom7Lack true leaves and rootsPhotosynthesis occurs in green stemsInstead of roots rhizoids are attached to underground stems called rhizomesKnobs on branches are sporophytesGametophytes develop from spores and live just below the surface of the soilLives symbiotically with fungus that lives in the gametophyte rhizoids. The gametophyte gets it nutrients from the fungusNeeds ample water for fertilizationWhisk ferns are the simplest vascular plant and resemble the first vascular land plants. They are among the earliest known vascular plants in the fossil record Club mosses- (1000 species) mostly small plants with small leaves and often grow in damp places (common name is ground pine)Named for club-shaped spore producing
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