Plant Diversity Chapter 29

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Plant Diversity Chapter 29

• What are the categories of Plants that exist?

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Figure 29.1 Some highlights of plant evolution
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4 major evolutionary trends

• Move to land
• Development of vascular tissue
• Development of seeds
• Development of flowers

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Charophyceans and similarity to plants

• Green algae
• Most closely related to land plants
• Have their own Kingdom? Viridiplantae
• 2 distinguishing features charophyceans and
  plants both have
• 1. rosette cellulose-synthesizing complexes
• 2. peroxisome enzymes are the same

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Figure 29.14 Three clades that are candidates
for designation as the plant kingdom
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Evidence for connection (see pages 582-583)

• Homologous chloroplasts
• Homologous cellulose walls
• Homologous peroxisomes
• Phragmoplasts
• Homologous sperm
• Key nuclear genes for ribosomal RNA and
  cytoskeletal proteins

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Figure 29.2 Charophyceans Chara (top),
Coleochaete orbicularis (bottom)
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Terrestrial adaptations that DIFFER from
plants.578-582

• charophyceans do NOT have
• -Apical meristems
• -Multicellular, dependent embryos
• -Alternation of generations
• -Walled spores produced in multicellular
  sporangia protected by sporopollenin (for air
  dispersal)
• -multicellular gametangia

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Figure 29.3 Apical meristems of plant shoots and
roots
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Figure 29.4 Embryos of land plants Marchantia
(left), Shepherd's purse (right)
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4 main groups of land plants

• Bryophytes mosses
• Pteridophytes ferns
• Gymnosperms conifers
• Angiosperms flowering plants

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Kingdom Plantae
Non-vascular Plants (Bryophytes) (no transport
tissues present)
Vascular Plants (Tracheophytes) (have vascular
tissue)
Seedless Plants (Pteridophytes)
Seed Plants
Angiosperms (flowering plants)
Gymnosperms
Monocots
Dicots
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Figure 22-7 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
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Table 29.1 Ten Phyla of Extant Plants
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Nonvascular Plants -- Bryophytes

• Simplest of plants
• Most have no vascular (transport) tissues no
  true stems, leaves, or roots
• Stay small and close to ground need to be near
  water to survive (absorption and reproduction)
• Have alternation of generation present for
  reproduction sporophytes (produce spores) and
  gametophytes (produce gametes)
• Offpsring develop from multicellular embryos that
  remain attached to mother plant
• Ex. Mosses, liverworts, hornworts

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Figure 29.6 Alternation of generations a
generalized scheme
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The Structure of a Moss
Section 22-2
Rhizoid
Go to Section
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Figure 29.16 The life cycle of Polytrichum, a
moss (Layer 1)
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Figure 29.16 The life cycle of Polytrichum, a
moss (Layer 2)
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Figure 29.16 The life cycle of Polytrichum, a
moss (Layer 3)
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Figure 29.16x Moss life cycle
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Figure 29.18 A moss sporangium with a
spore-shaker tip
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Figure 29.15 Bryophytes
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Figure 29.15x1 Hornwort
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Vascular Plants -- Tracheophytes

• Most commom and widespread of land plants
• Have true vascular tissues -- xylem and phloem
  -- that allow true organs to develop roots,
  stems, leaves
• Xylem carries water and minerals in a plant
• Phloem carries nutrients in a plant
• Two categories seedless and seed plants

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Figure 29.11 Xylem and phloem in the stem of
Polypodium, a fern (a pteridophyte)
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Seedless vascular plants

• Ex. Ferns
• Since dont have seeds, need LOTS of water for
  fertilization USE SPORES TO REPRODUCE FOR
  MAJORITY OF LIFE gametes are used only for a
  short period of time
• Display alternation of generations part of time
  is asexual (uses spores), part is sexual (uses
  gametes)

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Pteridophyta

• 2 Phyla
• Lycophyta lycophytes have small leaves
  (microphylls) with only a single unbranched vein
• Pterophyta ferns, whisk ferns, horsetails

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Figure 29.22 Hypotheses for the evolution of
leaves
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Figure 29.21x1 Lycophyte
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Figure 29.0 Ferns
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Figure 29.21 Pteridophytes club "moss" (top
left), whisk fern (top right), horsetail (bottom
left), fern (bottom right)
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Figure 29.21x2 Horsetail
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Figure 29.23 The life cycle of a fern
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Figure 29.24b Fern sporophyll, a leaf
specialized for spore production