Plants

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Plants
Orchid

• Characteristics
• Plant evolution
• Lower plants

Hornwort
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Characteristics of Kingdom

• Photosynthetic autotrophs
• Eukaryotic
• Chemistry same as for green algae
• Cell walls
• Pigments
• Multicellular
• Tissues organs
• Embryos

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Characteristics of Kingdom

• Life cycle alternation of generations
• Diploid sporophyte
• 
  meiosis
• zygote
  spores
• fertilization
• gametes
• Haploid gametophyte

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The Plant Life cycle

• Asexual reproduction common
• Sexual cycle involves alternation of two
  generations
• Gametophyte gametes, dependent on water (at
  first)
• Sporophyte spores, adapted to dry condition
• Trend in evolution reduction of the gametophyte
  (increased importance of sporophyte)

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Plant spores

• Produced by meiosis from sporophytes
• Haploid reproductive (dispersive) cells
• Grow into a gametophyte by mitosis
• Covered by sporopollenin

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Plant gametes

• Produced by gametophytes by mitosis
• Eggs sperm
• Fertilized egg (zygote) grows into sporophyte

Fern egg sperm
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Plant Development

• Embryos
• Young sporophytes develop from zygotes
• Protected and nurtured by parent

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Plant Body

• Root / Shoot
• Meristems
• growing points
• root/shoot tips
• (woody plants) sideways to form wood
• indeterminate growth

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Evolved from Charophycean Green Algae

• Mid Paleozoic
• Strong similarities
• Differences

Chara
A Coleochaete B Parka (Ordovician) From
Berkeley Time Machine
Coleochaete
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(No Transcript)
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Plant classification

• Bryophytes no seeds, no roots, no vascular
• Mosses, liverworts, hornworts
• Seedless, vascular plants no seeds
• Ferns, horsetails, club mosses, whisk ferns
• Gymnosperms - seeds cones
• Conifers, cycads, ginkgo, gnetophytes
• Flowering plants seeds, flowers fruits
• Primitive, Monocots, Dicots

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Non-vascular plantsBryophytes

• Mosses, liverworts, hornworts
• Gametophyte dominant
• No roots rhizoids
• Often dependent on available moisture
• Occupy ecological niches no other plants do
• Represent first plants

Moss
Liverwort
Hornwort
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Phylum Bryophyta Mosses

• Leafy gametophytes
• Sporophytes with complex teeth
• Evolutionarily distinct group from other
  bryophytes

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Moss Life Cycle

• Sporophyte
• Zygote
• Embryo nurtured by gametophyte
• Mature sporophyte with sporangium
• Gametophyte
• Spore
• Protonema
• Leafy gametophyte
• Gametes eggs sperm

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Moss Life Cycle
Male leafy gametophyte
Female leafy gametophyte
Protonema
Sporophyte Gametophyte
Spores
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Moss Life Cycle
Sperm from antheridia
Leafy gametophytes
Egg in archegonium
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Moss Life Cycle
Fertilization
Meiosis to form spores within sporangium
Young sporophyte
Zygote
Spore dispersal by wind
Embryo
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Moss Life Cycle
Sperm from antheridia
Egg in archegonium
Gametophyte
Fertilization
First thread stage
Sporophyte
Meiosis
Zygote
Spores
Embryo
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Moss links

• UBC Moss Class
• Microscopy UK

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Phylum Hepatophyta - Liverworts

• Sporophyte simpler than mosses
• Leafy
• Thallose

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Phylum Anthocerophyta - Hornworts

• Sporophyte linear tube with meristem at base
• Thalloid
• Closest bryophyte to ancestor of other plants

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Moss, Rhizomnium
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Moss, Tortula, whole leaf
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Sphagnum bog
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Sphagnum Peat Moss
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Thallose liverwort Marchantia
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Leafy liverwort Lophocolea
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Hornwort, Anthoceros