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Plants Overview

Plants Overview. Honors Biology Mrs. Mawhiney. Fig. 29-7. Origin of land plants (about 475 mya). 1. Origin of vascular plants (about 420 mya). 2. Origin of extant seed plants (about 305 mya). 3. Liverworts. Nonvascular plants (bryophytes). Land plants. Hornworts. ANCES- TRAL

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Plants Overview

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  1. Plants Overview Honors Biology Mrs. Mawhiney

  2. Fig. 29-7 Origin of land plants (about 475 mya) 1 Origin of vascular plants (about 420 mya) 2 Origin of extant seed plants (about 305 mya) 3 Liverworts Nonvascular plants (bryophytes) Land plants Hornworts ANCES- TRAL GREEN ALGA 1 Mosses Lycophytes (club mosses, spike mosses, quillworts) Seedless vascular plants Vascular plants 2 Pterophytes (ferns, horsetails, whisk ferns) Gymnosperms 3 Seed plants Angiosperms 50 500 450 400 0 350 300 Millions of years ago (mya)

  3. Seeds • Seeds changed the course of plant evolution, enabling their bearers to become the dominant producers in most terrestrial ecosystems • A seedconsists of an embryo and nutrients surrounded by a protective coat

  4. Concept 30.2: Gymnosperms bear “naked” seeds, typically on cones • The gymnosperms have “naked” seeds not enclosed by ovaries and consist of four phyla: • Cycadophyta (cycads) • Gingkophyta (one living species: Ginkgo biloba) • Gnetophyta (three genera: Gnetum, Ephedra, Welwitschia) • Coniferophyta (conifers, such as pine, fir, and redwood)

  5. Phylum Cycadophyta • Individuals have large cones and palmlike leaves • These thrived during the Mesozoic, but relatively few species exist today

  6. Fig. 30-5a Cycas revoluta

  7. Phylum Coniferophyta • This phylum is by far the largest of the gymnosperm phyla • Most conifers are evergreens and can carry out photosynthesis year round

  8. Fig. 30-5k Sequoia

  9. Angiosperms Nonvascular plants (bryophytes) Seedless vascular plants Gymnosperms Angiosperms • Angiosperms are seed plants with reproductive structures called flowers and fruits • They are the most widespread and diverse of all plants

  10. Fig. 30-7 Stigma Carpel Stamen Anther Style Filament Ovary Petal Sepal Ovule Video: Flower Blooming (time lapse)

  11. Fruits • A fruit typically consists of a mature ovary but can also include other flower parts • Fruits protect seeds and aid in their dispersal • Mature fruits can be either fleshy or dry Animation: Fruit Development

  12. Fig. 30-8 Tomato Ruby grapefruit Nectarine Hazelnut Milkweed

  13. Fig. 30-13n MonocotCharacteristics EudicotCharacteristics Embryos Two cotyledons One cotyledon Leafvenation Veins usuallyparallel Veins usuallynetlike Stems Vascular tissueusually arrangedin ring Vascular tissuescattered

  14. Fig. 30-13o MonocotCharacteristics EudicotCharacteristics Roots Taproot (main root)usually present Root systemusually fibrous(no main root) Pollen Pollen grain withone opening Pollen grain withthree openings Flowers Floral organsusually inmultiples of three Floral organs usuallyin multiples of four or five

  15. Monocots • More than one-quarter of angiosperm species are monocots

  16. Fig. 30-13e Orchid

  17. Fig. 30-13f

  18. Eudicots • More than two-thirds of angiosperm species are eudicots

  19. Fig. 30-13h California poppy

  20. Fig. 30-13j Dog rose

  21. The plant body has a hierarchy of organs, tissues, and cells • There are three basic plant organs: • Roots • Stems • Leaves

  22. Stems – function primarily to display the leaves. Terminal Bud – area of growth at the top end of stem Axillary Buds – area of growth located in the V area between the leaf and the stem (branches) Leaves – main photosynthetic organ in plants Shoot System: Stems and Leaves Reproductive shoot (flower) Apical bud Node Internode Apical bud Shoot system Vegetative shoot Blade Leaf Petiole Axillary bud Stem Taproot Lateral branch roots Root system

  23. There are three basic groups of plant tissues: • Dermal Tissue • Single layer of closely packed cells • Protects plant against water loss and invasion by pathogens and viruses • Cuticle – waxy layer in leaves • Vascular Tissue • Xylem and phloem • Ground Tissue • Any tissue that’s not Dermal or Vascular tissue • Pith – ground tissue located inside vascular tissue • Cortex – ground tissue located outside the vascular tissue

  24. Xylem conducts most of the water and minerals and includes dead cells called tracheids Water-conducting cells are strengthened by lignin and provide structural support Increased height was an evolutionary advantage Phloem consists of living cells and distributes sugars, amino acids, and other organic products Sugar-Conducting Cells of the Phloem Sieve-tube elements are alive at functional maturity, though they lack organelles Sieve plates are the porous end walls that allow fluid to flow between cells along the sieve tube Each sieve-tube element has a companion cell whose nucleus and ribosomes serve both cells Transport in Xylem and PhloemVascular plants have two types of vascular tissue: xylem and phloem

  25. Vegetative Propegation

  26. Tropical Tropismstropism – turning response to a stimulus

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