Plant Diversity I: The Colonization of Land

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Modern Protist Diversity
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Plant Clades
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Plant Clades
Phylum/Division Bryophyta
Phylum/Division Pterophyta
Phylum/Division Anthophyta
Phylum/Division Coniferophyta
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From Algae to Plants

• The ancestor of all plants was a green alga
• Green algae have plant-like chloroplasts,
  plant-like cell walls, and a plant-like energy
  storage molecule (starch) etc.
• The ancestor of plants probably was a green alga
  that lived whole or partially in very shallow
  water, perhaps susceptible to periodic drying up
• Those algae that could continue to metabolize
  despite not being completely covered with water
  presumably possessed a selective
  advantageincluding shading those algae
  restricted to water
• The first roots were stems (stipes) that
  physically connected out-of-water portions of
  algae with still-in-water portions
• Water diffused over short stems to keep
  above-water, actively photosynthesizing tissues
  from desiccating

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Chara
Gametangia
Antheridium
Oogonium
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The Challenges of Land

• Algae
• Get minerals and water from surrounding water
• Have their bodies supported by surrounding water
• Their sperm and spores swim through the water
• Plants
• Get their Minerals and Water from soil
• Soil is subject to desiccation
• Soil also is opaque to sunlight
• Do not have their weight supported by surrounding
  water
• Do not have, or have less water for sperm and
  spores to swim through
• To survive on land, plant ancestors had to
  address these challenges

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Evolution of First Plant
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Plant Innovations

• Waxy cuticles (water proofing)
• Stomata (holes in above)
• Dominant sporophyte
• Vascular tissue
• Woody tissue
• Pollen (non-motile sperm carrier also male
  gametophyte)
• Seeds (embryo carrier)
• Flowers
• Fruit

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Timing of Innovations
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Plant Innovations

• Waxy cuticles
• Stomata
• Dominant sporophyte
• Vascular tissue
• Woody tissue
• Pollen
• Seeds
• Flowers
• Fruit

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Waxy Cuticle
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Flaccid / Wilted
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Plant Innovations

• Waxy cuticles
• Stomata
• Dominant sporophyte
• Vascular tissue
• Woody tissue
• Pollen
• Seeds
• Flowers
• Fruit

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Gas Exchange
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Stomata
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Guard Cells
no Air in, no Water out
Air in, Water out
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Plant Innovations

• Waxy cuticles
• Stomata
• Dominant sporophyte
• Vascular tissue
• Woody tissue
• Pollen
• Seeds
• Flowers
• Fruit

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Dominant Sporophyte
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Plant Innovations

• Waxy cuticles
• Stomata
• Dominant sporophyte
• Vascular tissue
• Woody tissue
• Pollen
• Seeds
• Flowers
• Fruit

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Vasculature (etc.)
90 of water passed up through Xylem is
transpired out of plant through stomata
Photosynthate moves down from leaves, Minerals
and Water move up from roots
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Plant Innovations

• Waxy cuticles
• Stomata
• Dominant sporophyte
• Vascular tissue
• Woody tissue
• Pollen
• Seeds
• Flowers
• Fruit

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Cellulose ? Cell Walls
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Lignin ? Woody Tissue
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Fungi ? Aerobic Decay
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Coal ? Anaerobic Decay
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Plant Innovations

• Waxy cuticles
• Stomata
• Dominant sporophyte
• Vascular tissue
• Woody tissue
• Pollen
• Seeds
• Flowers
• Fruit

Alternation of Generations
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Alternation of Generations
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Alternation of Generations
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Syngamy
Isogametes
Anisogametes
Oogamy
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Chara Only Zygote is Diploid
Gametangia
Zygote
Antheridium
Oogonium
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Delaying Meiosis
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Fruit and Seeds

• Pericarp
• the fruit wall (derived from the ovary of the
  pistil) which is composed of the exocarp,
  mesocarp and endocarp (the three layers are not
  always recognizable, eg. dry fruit)

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Parts of a fruit

• Peach
• Endocarp
• the innermost layer of the pericarp (often hard,
  stony or papery) 
• Mesocarpthe middle layer of the pericarp (often
  fleshy)
• Exocarp  
• the outermost layer of the pericarp (often like a
  skin or peel).

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Parts of a fruit

• Rind--Lemon
• tough, leathery covering on manyfruits either
  composed of the exocarp (melon) or the exocarp
  and mesocarp (orange).

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Parts of a fruit

• Apple
• accessory tissue
• fruit parts not directly derived from the ovary,
  for example, receptacle tissue of pomes (apple)
  and the husks of nuts (acorn, pecan).

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Simple Fruit
legume  or  pod

• derived from a single flower with a single ovary
  (pistil).
• dry dehiscent fruit--pericarp splits open at
  maturity.legume  or  pod contains one locule
  that splits along two sutures. (bean, pea,
  peanut, mimosa)

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follicle

• contains one locule that splits along one or more
  suture. (larkspur, sweet gum,  magnolia)

Follicle--Sweet Gum and Magnolia
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capsule

• contains three or more locules that split along
  three or more sutures. (okra, golden rain tree,
  tallow tree)

Okra
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Dry indehiscent fruit-

• pericarp dries, but does not split open at
  maturity.
• Samara
• one or two seeded with pericarp  flattened
  into wings.  (maple, ash)

Ash
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Caryopsis  or  grain

• one seeded fruit with seed fused to the pericarp.
  (wheat, corn, grain)

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Achene

• one seeded fruit with seed free from pericarp.

Sunflower
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Nut

• similiar to an achene, but one seeded by abortion
  and partially (acorn) or entirely  enclosed by a
  husk. (pecan, walnut)

Pecan and Oak
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Fleshy fruit

• pericarp does not dry at maturity
• Berry
• entire pericarp is fleshy. (grape, tomato)

Tomato
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Pepo

• a type of berry, with the exocarp as a hard rind.
  (melon, cucumbers, squash)

Squash
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Hesperidium

• a type of berry, with the exocarp and mesocarp as
  a hard rind and the endocarp composed of juice
  vesicles. (citrus-orange, lemon, lime)

Lemon
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Drupe  or  stone

• a single-seeded fruit with a skin-like exocarp
  (fuzzy or smooth) fleshy mesocarp and a hard
  stony endocarp. (peach, cherry, plum, coconut)

Peach
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Pome

• a paper-like pericarp containing a thickened,
  fleshy receptacle or hypanthium. (apple, pear,
  pomengranate)

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Dry and fleshy fruits
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Aggregate Fruit

• a fruit derived from a single flower with many
  pistils. (blackberry, strawberry)

Strawberry
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Multiple Fruit

• a fruit derived from several or multiple flowers
  clustered along a common axis. (mulberry, fig,
  pineapple

Pineapple
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More Spores / Fertilization
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Ulva

• Green Algae
• Alternation of Generations
• Isomorphic
• Isogamic

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Laminaria

• Brown Algae
• Alternation of Generations
• Heteromorphic
• Oogamic
• Conspicuous Sporophyte

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Bryophyte Life Cycle

• Plant (modified green algae)
• Alternation of Generations
• Heteromorphic
• Oogamic
• Conspicuous Gametophyte

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Bryophyte Clades
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Liverwort Life Cycle
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Hornwort (Bryophyte)
Sporophyte
Gametophyte
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Pteridophyte Clades
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Lycophytes
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Recall Bryophyte Life Cycle
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Pterophyte Life Cycle
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Plant Innovations

• Waxy cuticles
• Stomata
• Dominant sporophyte
• Vascular tissue
• Woody tissue
• Pollen
• Seeds
• Flowers
• Fruit

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Comparative Life Histories
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Comparative Life Histories
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Some Seed-Bearing-Plant Anatomy
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Homospory
Most Ferns are Homosporous
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Heterospory
Seed-Bearing Plants often are Heterosporous
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Homo vs. Heterospory
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Plant Innovations

• Waxy cuticles
• Stomata
• Dominant sporophyte
• Vascular tissue
• Woody tissue
• Pollen
• Seeds
• Flowers
• Fruit

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Pollen
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Heterospory
This is Pollen!
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Pollen Pollen Tube
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Plant Innovations

• Waxy cuticles
• Stomata
• Dominant sporophyte
• Vascular tissue
• Woody tissue
• Pollen
• Seeds
• Flowers
• Fruit

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Ovule to Seeds
Sporangium
Gametangium
Sporophyte (grandparent)
Gametophyte (haploid parent)
Progeny (next generation)
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Seeds
Dicot
Monocot
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Recall Pterophyte Life Cycle
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Coniferophyte Life Cycle
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Coniferophyte Life Cycle
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Plant Innovations

• Waxy cuticles
• Stomata
• Dominant sporophyte
• Vascular tissue
• Woody tissue
• Pollen
• Seeds
• Flowers
• Fruit

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Flower
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Flower Cross Section
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Pigmented Sepals
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Evolutoin of Flower Structure
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Recall Coniferophyte Life Cycle
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Anthophyte Life Cycle
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Double Fertilization
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Seven-Cell Gametophyte
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Plant Innovations

• Waxy cuticles
• Stomata
• Dominant sporophyte
• Vascular tissue
• Woody tissue
• Pollen
• Seeds
• Flowers
• Fruit

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Fruit
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Flower to Fruit
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Monocot vs. Dicot
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Monocot
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Dicot
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Overview Bryophytes (moss)
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Overview Pterophytes (ferns)
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Overview Coniferophytes (pines)
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Overview Anthophytes (flowering)
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(No Transcript)
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Link to Next Presentation
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Acknowledgements
http//www.abdn.ac.uk/gen155/lectures/l3420webve
rsion.ppt Note that the previous fruit lecture is
from http//www.ideal.upm.edu.my/ideal/tugasan/b
acelor/BGY3201_presentation1.ppt
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Fruit
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Fruit