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Plant Diversity Chapter 22

Plant Diversity Chapter 22. What is a Plant?. Plants are the base for the food chain on land. Provide shade, shelter and oxygen Evolved more than 470 million years ago Multicellular, Eukaryotes Cell walls made of cellulose Photosynthesis using chlorophyll a and b

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Plant Diversity Chapter 22

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  1. Plant DiversityChapter 22

  2. What is a Plant? • Plants are the base for the food chain on land. • Provide shade, shelter and oxygen • Evolved more than 470 million years ago • Multicellular, Eukaryotes • Cell walls made of cellulose • Photosynthesis using chlorophyll a and b • Most are autotrophs; few parasites + saprobes • Ex. Trees, shrubs, grasses, mosses and ferns

  3. Life Cycle • Haploid (N)-Gametophyte; gamete-producing • Diploid (2N)-Sporophyte; spore-producing • Produce a new individual by mitosis • All plants have both phases, but in different forms • Can reproduce independently of water • Some also reproduce asexually (vegetative)

  4. MEIOSIS Haploid Diploid FERTILIZATION Generalized Plant Life Cycle Section 22-1 Spores(N) Sperm(N) Eggs(N) Go to Section:

  5. Plant Survival • Sunlight • Water and Minerals • Taken up through the roots • Movement of Water/Nutrients • Make food in their leaves • Water and nutrients carried upward through tissue from soil • Gas Exchange

  6. Early Plants • Evolved from multicellular green algae • First plants were dependent on water • Similar to today’s mosses in structure and growth close to the ground • Evolved different adaptations for terrestrial environments

  7. Cone-bearingplants Ferns andtheir relatives Seeds Water-Conducting(Vascular) Tissue Cladogram of Plant Groups Section 22-1 Go to Section:

  8. Overview of the Plant Kingdom • Divided into four groups based on water-conducting tissues, seeds and flowers • Reproductive structures and body plan are also considered • Compare DNA sequences of various species • Deep Green (1994)-Evidence that first plants evolved from green algae that lived in fresh water

  9. The Diversity of Plants Section 22-1 Cone-bearing plants760 species Floweringplants235,000 species Ferns andtheir relatives11,000 species Mosses andtheir relatives15,600 species Go to Section:

  10. Bryophytes Nonvascular plants 1) Mosses (in swamps) • Can live in harsh environments • Rhizoid-long, thin cells absorb water and minerals and anchor them to the ground 2) Liverworts and 3) hornworts • Use osmosis to draw up water • Water needed for reproduction • Act as natural sponge and form peat moss

  11. Bryophytes • Mosses Liverworts Hornworts • http://www.ghettodriveby.com/hornworts/

  12. Seedless Vascular Plants • Vascular tissue-Specialized to conduct water and nutrients thought he body of the plant • Xylem-form of vascular tissue that carries water upward from the roots to every part of the plant • Phloem-transports solutions of nutrients and carbohydrates from photosynthesis • Tree rings in the lower trunk indicate the tree age • Formed by cell division in thin layers inside bark • Width of the bands indicate environmental conditions for each year (Ex. Drought conditions)

  13. Ferns • Evolved 350 million years ago • Roots-Underground organs to absorb water and minerals with water-conducting tissue • Leaves-Photosynthetic organ that contain bundles of vascular tissue • Veins-Made of xylem and phloem • Stems-Connect roots and leaves

  14. Seed Plants • Gymnosperms-Seeds on cone surfaces • Conifers, Cycads, Ginkgoes and gnetophytes • Angiosperms-Flowering plants with seeds in tissue layers • Flowers or cones transfer sperm by pollination and protect embryos in seeds • Life cycle alternates between gametophytes and sporophyte

  15. Seed coat Seed Embryo Storedfood supply The Structure of a Seed Section 22-4 B A Go to Section:

  16. Reproduction without Water • Cones-sporophyte structures which are seeding bearing for gymnosperms • Flowers-Seed-bearing structure of angiosperms • Pollen Grains-Contain male gametophytes • Seeds-Embryo of seed plant with seed coat and food supply • Eaten and dispersed by animals or stick to their fur • Fossils from 30 million years ago

  17. A Bee With Pollen On It’s Leg

  18. Gymnosperms • Cone Bearers / “naked seed” • Gnetophytes: a) Ex. Welwitschia-Namibian desert with large, leathery leaves; spread across the ground • Cycads- (Cycadophyta): a) Palm-link plants with large cones b) Appeared during Triassic Period (225 million years ago) c) Grow in tropical and subtropical places

  19. Welwitschia mirabilis,a Gnetophyte. And Zamia pseudoparasitica,a Cycad.http://www.conifers.org/pinophyta.htm

  20. Gymnosperms • Ginkgoes-Only Ginkgo biloba currently exists • One of the oldest seed plant species alive today • Cultivated in China and planted around temples • Often planted in urban settings in U.S. due to resistance to air pollution • Conifers-(Coniferophyta) • Ex. Pines, spruces, firs, cedars, sequoias, redwoods • Long, thin leaves (Ex. Pine needles)-reduces surface area, waxy layer • Most are “evergreens” with cycling of needles

  21. Ginkgo and Pseudotsuga menziesii,a Conifer. http://www.conifers.org/pinophyta.htm

  22. Angiosperms • Phylum Anthophyta “enclosed seed” • Cretaceous Period (135 million years ago) arrival • Dominate Earth’s plant life • Reproduce with flowers or fruits • Ovary develops into fruits to protect seed and for dispersal • Fruit-thick wall of tissue surrounding the seed

  23. Seed Dispersal By Wind And General Flower Structurehttp://science.kennesaw.edu/biophys/biodiversity/plants/plpix5.htm

  24. Monocots and Dicots • Cotyledons-Seed leaves in the plant embryo • Monocots-One seed leaf, parallel veins, multiples of 3 floral parts, vascular bundles scattered and fibrous roots • Dicots-Two seed leaves, branched veins, multiples of 4 or 5 floral parts, vascular bundles in a ring and a taproot

  25. Single cotyledon Two cotyledons Parallel veins Branched veins Floral parts often in multiples of 3 Floral parts often in multiplesof 4 or 5 Vascularbundlesscattered throughout stem Vascularbundlesarranged ina ring Fibrous roots Taproot Comparison ofMonocots and Dicots Section 22-5 Monocots Dicots Seeds Leaves Flowers Stems Roots Go to Section:

  26. Monocots and Dicotshttp://www.emc.maricopa.edu/faculty/farabee/biobk/BioBookPLANTANATII.html

  27. Diversity of Angiosperms • Wood plants made of cells with thick cell walls (Trees, shrubs and vines) • (Ex. Grapes and Ivy vines) • (Ex. Blueberries and rose bushes) • Herbaceous plants-No wood production as they grow (Ex. Dandelions, zinnias, sunflowers and petunias)

  28. Rose Bush, Grape Vine, Zinnias and Petuniashttp://www.flowers.vg/flowers/petunia01.htm

  29. Diversity of Angiosperms • Annuals-Complete a life-cycle within one growing season • (Ex. Marigolds, petunias, pansies, zinnias, wheat and cucumbers) • Biennials-Complete their life cycle in 2 years • Year 1-germinate and grow roots & very short stems • Year 2-Grow new stems and leaves and produce flowers and seeds • (Ex. Primrose, parsley, celery) • Perennials-Live for more than 2 years • (Ex. Asparagus, grasses-herbaceous stems) • (Ex. Maple trees-wood stem)

  30. Primrose, Marigolds, Ornamental Grasseshttp://landscaping.about.com/cs/designexamples1/l/bllandscaping10.htm

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