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Note that the following is a rudimentary outline of the class lecture; it does not contain everything discussed in class. Land Plants Introduction to Land Plants No terrestrial organisms until Formation of _____________ protection for organisms Plants or plant ancestors moved from ________________ to ___________________ environments Why Move to land? Problems with Moving to Land Lack – – – environment – – procurement & transport – – Lecture 2 - Land Plants Structural Specialization Earliest plants were probably Over time developed more defined – Some plants developed – an advantage in Water and Nutrient Transport Roots, stems, and leaves have (not found in ) Two types of tissues conduct materials: – Carries H2O & inorganic nutrients in one direction, from roots to stem & leaves – distributes organic compounds (sugars, amino acids, etc.) in any direction, depending on plant needs Preventing Water Loss Development of – a waxy waterproof layer on surface of leaves, stems and other aerial parts – helps conserve water; slows evaporation – pores on surface of – allow the exchange of – – close BIOL 1030 border to minimize in hot, dry conditions 2 Lecture 2 - Land Plants Reproduction Early land plants needed for reproduction sperm had to swim through probably lived in Overtime developed and that protected reproductive cells from drying out Reproduction – contains a reproductive cell ( ) surrounded by a hard outer – widespread dispersal of plant species – Multicellular embryo ( – may contain ) surrounded by a protective , nourishment for the developing embryo – more effective at than spores Kingdom Plantae ~ described living species General characteristics • eukaryotic, multicellular, cell walls rich in • most photosynthetic, chloroplasts containing • • found in lifecycle communities • source of BIOL 1030 3 Lecture 2 - Land Plants Kingdom Plantae Two Main Groups: plants and – plants plants divided into those without and those with ( producing) Will be looking at • Highlights of Plant Evolution Fig 29.7 Land Plant Traits appear in nearly all land plants absent in the Charophyceans Apical Meristems Fig 29.5 Alternation of Generations Fig 13.6b Walled Spores Produced in Sporangia Fig 29.5 Multicellular Gametangia Fig 29.5 Multicellular Dependent Embryos Fig 29.5 BIOL 1030 4 Lecture 2 - Land Plants Spore versus Gamete (n) – can develop into a new organism (n) – sperm, egg – gamete must combine with another gamete to produce a Bryophytes Bryophytes – mosses – hornworts – liverworts Fig 29.10 Bryophyte Morphology Gametophyte (eg. Polytrichum moss) – mass of green, branched, one-cell-thick filaments – colorless, tubular single cells or filaments – anchoring BIOL 1030 5 Lecture 2 - Land Plants – mature, gamete-producing structure Bryophyte Morphology Sporophyte – absorbs nutrients from gametophyte – elongated stalk – site of spore production – protective cap of gametophyte tissue – ring of tooth-like segments Bryophyte Reproduction – found on the sporophyte generation of a plant – spore mother cells - meiosis - spores ( ) – walls - polymer – most durable organic material, makes walls very tough and resistant to – grow into multicellular, haploid gametophytes by mitosis BIOL 1030 6 Lecture 2 - Land Plants Bryophyte Reproduction – formation of gametes, two types – a vase-shaped organ produces a single egg cell retains egg in base of organ – produce many sperm cells that are released to environment when mature Life cycle of Polytrichum (moss) Fig 29.8 Bryophyte Reproduction Summary lifecycle are the most conspicuous, dominant phase are typically smaller and present only part of the time BIOL 1030 7 Lecture 2 - Land Plants Seedless Vascular Plants Seedless Vascular Plants Lycophytes - Fig 29.14 Seedless Vascular Plants Pteridophytes - Fig 29.14 Fern Morphology – leaf-like part of sporophyte – immature – the stalk or base of the frond – the continuation of stipe into blade – photosynthetic portion of frond – a segment of leaf blade BIOL 1030 8 Lecture 2 - Land Plants Fern Morphology – cluster of sporangia; shape & location used for identification (+ or -) – covering over a sorus; often thin and fragile; shape, attachment and location used for identification (+ or -) – a belt of cells with horseshoe thickened walls surrounding the sporangium – some cells are unthickened; as the sporangium dries out they break to release the spores Fern Life Cycle Fig 29.14 Spore Development and Terminology Homospory spores functionally spores give rise to ________________ (bisexual) gametophytes single gametophyte will have _____________ (produce eggs) and _____________ (produce sperm) BIOL 1030 9 Lecture 2 - Land Plants Heterospory two functionally spores give rise to _________________ (two unisexual; dissimilar) gametophytes ____________ (large) produce ______________ (female gametophytes) with spores _____________ _________ (smaller), produce _________________ (male gametophyte) with ______________ Spore Type Club mosses Ferns mostly some Whisk ferns Horsetails Seed Plants Gymnosperms Pinus Reproduction Sexual reproduction extremely slow Pinus sporophyte ____________________ has both sexes on same plant BIOL 1030 10 Lecture 2 - Land Plants cone – male; small – form clusters on the tips of ________________ branches cone – female; larger (up to long) – located on _______________ branches Sporophyll scale Megasporophyll (ovuliferous scale) – Microsporphyll - Ovulate Cone Female Reproductive Terminology – a protective structure in which the female gametophyte develops – layers of sporophyte tissue that contribute to the structure of the ovule – central part of ovule; contains the embryo sac – undergoes meiosis to produce 4 megaspores, 3 degenerate Gymnosperm Seed Development Fig 30.3 - Unfertilized ovule BIOL 1030 11 Lecture 2 - Land Plants Staminate Cone Pollen Grain Development Gymnosperm Seed Development Fig 30.3 Fertilized ovule Gymnosperm seed Pinus Lifecycle Fig 30.6 Pinus Seed BIOL 1030 12
