TEST 3 Plant diversity II The Evolution of Seed Plants Chapter 30 Concept 30 1 Seeds and pollen grains are key adaptations for the life on land Characteristics common to all seed plants 1 Seeds 2 Reduced gametophytes 3 Heterospory 4 Ovules females gametophyte is housed 5 Pollen male gametophyte is housed Gametophyte sporophyte relationships Figure 30 2 Gametophytes of seed plants develop with in the walls of spores retained within the tissues of the parent sporophyte No longer dependent on water for fertilization Ovules and Production of Eggs An ovule consists of a megasporangium megaspore and protective integuments Figure 30 3a Pollen and Production of Sperm Microspores develop into pollen grains o Contain male gametophyte If a pollen grain germinates Pollen can be dispersed by air or animals eliminates the need for water in fertilization It gives rise to a pollen tube that discharges sperm into the female gametophyte within the ovule Figure 30 3b A seed Develops from the whole ovule Includes sporophyte embryo 2n food supply female gametophyte tissue n protective coat derived from the integument Figure 30 3c Clicker Which does not apply to gymnosperms or angiosperms Clicker In seed bearing plants microspores develop into 1 Vascular tissues 2 Diploid dominance 3 Single spore type 4 Cuticle with stomata 1 Ovules 2 Seeds 3 Pollen grains 4 Anthers Concept 30 2 Gymnosperms bear naked seeds typically on cones Gymnosperms include Phylum Cycadophyta o Sago palms Phylum Gingkophyta Phylum Gnetophyta Phylum Coniferophyta Figure 30 5 o One species called gingkophylota o Pines o Firs o Junipers o Sequoias A Closer Look at the Life Cycle of a gymnosperm Key features of the gymnosperm life cycle include 1 Dominance of the sporophyte generation 2 The role of pollen in transferring sperm No water required 3 The development of seeds from fertilized ovules Pine life Cycle Clicker How many generations are represented in the seed of a gymnosperm Figure 30 6 1 1 2 2 3 3 4 4 Clicker Gymnosperms include Cycads conifers ginkgo biloba and gnetophytes Concept 30 3 The reproductive adaptations of angiosperms include flowers and fruits Angiosperms a k a flowering plants o covered seeds Derived traits are the reproductive sturctures called flowers and fruits The most widespread and diverse of all plants o 250 000 species o 90 of all extant plant species Angiosperm Diversity Figure 30 12 From Figure 30 13 Monocots parallel veins and dicots figure 30 13 1 Monocot 2 Eudicot 3 Bryophyte 4 Conifer Flowers Clicker One difference between gymnosperms and angiosperms is that 1 only angiosperms reproduce sexually 2 only angiosperms produce fruits 3 only angiosperms produce seeds 4 only angiosperms produce wood Clicker If an angiosperm plant embryo contains two seed leaves the plant is a Specialized for sexual reproduction Specialized shoot with modified leaves o Sepals enclose the flower o Petals brightly colored attract pollinators o Stamens produce pollen male o Carpels produce ovules female o Fruits A mature ovary o Ovary matures after fertilization of ovules Can be carried by wind water or animals enhancing dispersal o The Angiosperm Life Cycle with in an ovules Double fertilization occurs when a pollen tube discharges 2 sperm into the female gametophyte o 1st sperm fertilizes the egg o 2nd sperm combines with 2 nuclei in the center cell of the female gametophyte and initiates development of endosperm Endosperm nourishes the developing embryo Clicker Gymnosperms and angiosperms have the following traits in common except 1 seeds 2 pollen 3 vascular tissue 4 ovaries 5 ovules Clicker With respect to angiosperms which of the following is incorrectly paired with its chromosome count 1 Egg Cell n 2 Megaspore 2n 3 Microsporocyte 2n 4 Endosperm 3n CHAPTER 35 Plant Structure Growth and Development Concept 35 1 The plant body has a hierarchy of organs tissues and cells The Tree Basic Plant Organs Plants draw nutrients from 2 very different environments below ground and above ground Three Basic organs o Roots o Stems o Leaves Organized into the root and shoot system o Roots An organ that anchors the vascular plant Absorbs minerals and water o Absorption occurs near root tips o Root hairs increase the surface area of the root Stores organic nutrients o Stems consists of o Nodes points at which leaves are attached o Internodes segment between nodes o Axillary buds potential to form lateral shoot i e branch o Terminal bud located at shoot tip causes elongation of a young shoot o Leaves The leaf is the main photosynthetic organ of most vascular plants Consist of o A flattened blade o The petiole which joins the leaf to a node of the stem Simple vs Compound Leaves Simple leaf a single undivided blade o Some may have deep lobes Compound leaf blade consists of multiple leaflets Doubly compound leaf each leaflet is divided into smaller leaflets The Three Tissue Systems Dermal Vascular and Ground Dermal consists of the epidermis and periderm Vascular carries out transport of materials between roots and shoots o Xylem conveys water and minerals up from roots o Phloem transports organic nutrients from sources originating from to sinks where its going to be used o Ground tissue various functions including storage photosynthesis and support o Differentiated Plant Cells Parenchya Collenchyma stems Sclerenchyma o Thin flexible 1 cell walls alive at maturity carry out most metabolism with in a plant o Unevenly thickened but flexible 1 cell walls alive at maturity supports young growing o Thick rigid 2 cell walls dead at maturity provides support Xylem conducts water and minerals from roots o Tubular Cells dead at maturity cell walls Vessel elements short wide tubular cells Phloem conducts organic compounds Tracheids thin tubular cells cell walls contain pits thin regions with only 1 degree o Sieve tube members conducting cells alive but not many organelles o Companion cells nonconducting cells alive and supports sieve tube members Clicker Unlike collenchyma and sclerenchyma tissues parenchyma tissue does not function in 1 Support 2 gas exchange 3 nutrient exchange 4 both gas exchange and nutrient exchange Concept 35 2 Meristems generate cells for primary and secondary growth Meristems Apical meristems are located at the tips of roots and in the buds of shoots o Elongate shoots and roots through primary growth Lateral meristems or cambia run parallel to the long axis of roots and shoots o Adds thickness to woody plants through secondary
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