Chapter 30 Plant Diversity II The Evolution of Seed Plants Concept 30 1 Seeds and pollen grains are key adaptations for life on land Characteristics common to all seed plants o Seeds o Reduced gametophytes o Heterospory some spores develop into a female gametophyte and others develop into a male gametophyte o Ovules where the gametophytes are produced and housed in seed bearing plants o Pollen Gametophyte Sporophyte Relationships Figure 30 2 Gametophytes of seed plants develop within the walls of spores retained within tissues of the parent sporophyte No longer dependent on water for fertilization Ovules and Production of Eggs An ovule consists of a megasporangium 2n megaspore n and protective integuments Figure 30 3a Pollen and Production of Sperm Microspores develop into pollen grains o Contain male gametophyte Pollen can be dispersed by air or animals eliminates the need for water in fertilization If a pollen grain germinates it gives rise to a pollen tube that discharges sperm into the female gametophyte within the ovule o Figure 30 3b A Seed A seed develops from the whole ovule Includes sporophyte embryo food supply and protective coat Clicker Q Which does not apply to gymnosperms or angiosperms o Figure 30 3c o Vascular tissue o Diploid dominance o Single spore type o Cuticle with stomata Clicker Q In seed bearing plants microspores develop into pollen graisn Concept 30 2 Gymnosperms bear naked seeds typically on cones Gymnosperms Gymnosperms include o Phylum Cycadophyta i e sago palms o Phylum Gingkophyta o Phylum Gnetophyta o Figure 30 5 o Phylum Conifers Conifers cone bearing gymnosperms Pines firs junipers and sequoias Figure 30 5 Life Cycle of Gymnosperms Key features of the gymnosperm life cycle include o Dominance of the sporophyte generation o The role of pollen in transferring sperm to ovules No water required o The development of seeds from fertilized ovules Pine Life cycle o Figure 30 6 Clicker Q How many generations are represented in the seed of a gymnosperm 3 generations Clicker Q Gymnosperms include Cycads conifers and Ginkgo biloba 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 structure 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 o Figure 30 12 o Figure 30 13 Example test question the following four characteristics are found in the what is the exception Flowers Specialized for sexual reproduction Specialized shoot with modified leaves o Sepals enclose the flower o Petals brightly colored attract pollinators o Stamens produce pollen o Carpels produce ovules Figure 30 7 reproductive parts of a flower Fruits Fruits a mature ovary o Ovary matures after fertilization of ovules Can be carried by wind water or animals enhancing dispersal Figure 30 8 Figure 30 9 Angiosperm Life Cycle Double fertilization occurs when a pollen tube discharges 2 sperm into the female gametophyte within an ovule o 1st sperm fertilizes the egg o 2nd sperm combines with two nuclei in the center cell of the female gametophyte and initiates the development of the endosperm Endosperm nourishes the developing embryo Clicker Q Gymnosperms and angiosperms have the following traits in Figure 30 10 common except o Seeds o Pollen All seeded plants produce pollen There are seed bearing vascular plants o Vascular tissue o Ovaries o Ovules paired with its chromosome count o Egg cell n o Megaspore 2n o Microsporocyte 2n o Endosperm n Spores are always haploid due to meiosis Clicker Q With respect to angiosperms which of the following is incorrectly Chapter 35 Plant Structure Growth and Development Concept 35 1 The plant body has a hierarchy of organs tissues and cells Plants draw nutrients from 2 very different environments below ground and The Three Basic Plant Organs above ground 3 basic organs of a plant 1 The root 2 The stems 3 The leaves Organized into the root and shoot system Figure 35 2 Roots 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 Figure 35 2 Stems Consist of o Nodes points at which the leaves are attached o Internodes segment between nodes o Axillary buds potential to form lateral shoot i e branch o Terminal buds located at shoot tip causes elongation of a young shoot Figure 35 2 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 Figure 35 2 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 Clicker Q One difference between gymnosperms and angiosperms is that Figure 35 6 only angiosperms produce fruits Clicker Q If an angiosperm plant embryo contains two seed leaves the plant is a eudicot 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 to sinks Ground tissue various functions including storage photosynthesis and support Figure 35 8 Differentiated Plant Cells Parenchyma thin flexible 1o cell walls alive at maturity carry out most metabolism within plant Collenchyma unevenly thickened flexible 1o cell walls alive at maturity supports young growing stems Sclerenchyma thick rigid 2o cell walls dead at maturity provides support Figure 35 10 Xylem Xylem conducts water and minerals from roots Tubular cells dead at maturity o Tracheids thin tubular cells cell walls contain pits thin regions with only 1o cell walls o Vessel elements short wide tubular cells Phloem Phloem conducts organic compounds o Sieve tube members conducting cells alive but not many organelles o Companion cells non conducting cells alive and supports sieve tube members Figure 35 10 Clicker Q Unlike collencyma and sclerenchyma tissues parenchyma tissue does not function in support Concept 35 2 Meristems generate cells for primary and secondary growth Apical meristems are located at the tips of roots and in the buds of shoots o Elongate shoots and roots through primary growth
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