Classification III: Kingdom Plantae

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Classification IIIKingdom Plantae

• AP Biology

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Kingdom Plantae

• Plants had to adapt to life outside water to
  prevent drying out, still allow gametes to
  travel, and prevent UV radiation damage
• Dipoid sporophyte generation 2 copies of each
  chromosome allow recessive mutations to be masked
• Cuticle waxy covering to prevent dessication
• Vascular system water distribution throughout
  the plant, later xylem for water phloem for
  food
• Pollen gametes packaged for easy delivery
• Ovary protection for gametophytes
• Seasonal variation deciduous and desert annuals

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Phylum 1. Bryophyta

• Mosses, liverworts, hornworts
• Produce haploid spores via meiosis (wind borne)
• Lack vascular system
• No true roots, true stems, or true leaves
• Remain small
• Water must be available for absorption through
  surface tissues and as a transport medium for
  sperm (flagellated)

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Bryophyta
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Tracheophytes (vascular plants)

• The next divisions are vascular plants
• Possess xylem and phloem
• Have true roots, stems and leaves
• In first 3 Lycophyta, Sphenophyta, Pterophyta
• Produce flagellated sperm which swim to fertilize
  the eggs
• Diploid zygote produced, which grows in to the
  sporophyte

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Phylum 2. Lycophyta

• 2 Groups
• 1. Now extinct woody trees common in
  Carboniferous period (300 mya)
• 2. Tropical epiphytes (plants that live on other
  plants) and small herbaceous plants (club mosses)

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Phylum 3. Sphenophyta

• Extinct woody trees common during Carboniferous
  period
• Horsetails
• Hollow, ribbed stems that are jointed at nodes
• Nodes produce small scale-like leaves and
  sometimes branches
• Bushy branches give the appearance of a horsetail
• Stems, branches and leaves are green and
  photosynthetic

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Sphenophyta
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Phylum 4. Pterophyta

• Ferns
• Clusters of sporangia called sori develop on the
  undersurface of fern fronds
• Sporangia undergo meiosis and produce spores

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Seed Plants

• Two kinds of spores produced male female
• Microsporangia produce microspores (male)
• Macrosporangia produce macrospores (female)
• Microspores produce 4 haploid cells that mature
  into pollen
• Megaspores produce 1 surviving haploid megaspore
  which becomes 1 egg (flowering plants) or 2 eggs
  (conifers)
• When pollen contacts the megasporangium, a tube
  directs the pollen to the egg

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Phylum 5. Coniferophyta

• Conifers (cone-bearing) pines, firs, spruce,
  junipers, redwoods, cedars, and others
• Male and female reproductive structures are in
  pollen-bearing male cones and ovule-bearing
  female cones
• Gymnosperms naked seeds
• Fertilization and seed development is lengthy,
  requiring 1-3 years

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Conifers
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Phylum 6. Anthophyta

• Angiosperms (flowering plants)
• Parts of the flower
• Carpel (or pistil) female reproductive structure
• Ovary, Style, Stigma
• Stamen male reproductive structure
• Anther (pollen-bearing), Filament (stalk)
• Petals sometime Sepals function to attract
  pollinators

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Angiosperm Flowers

• The flower is a major evolutionary advancement
• Special adaptation to attract pollinators
• Ovules are protected inside an ovary
• Ovary develops into a fruit which fosters the
  dispersal of seeds by wind, insects, birds,
  mammals, and other animals

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Angiosperm Fertilization

• Pollen lands on sticky stigma
• Pollen tube grows down style toward ovule
• 2 sperm cells inside the pollen tube
• 1 diploid nucleus formed, and 1 triploid nucleus
  formed (becomes endosperm) this is called double
  fertilization
• Endosperm provides nourishment for embryo and
  seedling

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Angiosperms

• Additional advancements
• More specialized vascular tissues
• Numerous variations in habit and growth
• Result advanced survival ability in a variety of
  environmental conditions

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Kingdom Plantae
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Angiosperm Groups

• Divided into monocots dicots

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Plant Tissues

• Ground Tissues
• Parenchyma cells storage, photosynthesis,
  secretion
• Collenchyma cells mechanical support
• Sclerenchyma cells also mechanical support
• Dermal Tissue
• Epidermis cells secrete waxy cuticle
• Vascular Tissue
• Xylem conducts water/minerals
• Phloem conducts sugar/starches produced in
  photosynthesis

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Roots and Shoots

• Most growth occurs at the tips of roots and
  shoots
• Apical meristems area of primary growth
• Primary growth gives plants height, length in
  roots at apical meristems
• Secondary growth widens plant girth

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Monocot Root
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Dicot Root
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Monocot Stem
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Dicot Stem
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Leaves
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Cohesion-Tension Theory