THE PLANT KINGDOM

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THE PLANT KINGDOM
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All Plants Evolved from Common Ancestor Ancient
Green Algae

• Cell walls made of cellulose
• Store excess carbohydrates as starch
• Form a cell plate during cytokinesis
• Have same photosynthetic pigments
• Chlorophyll a and b
• Carotenoid carotene and xanthophyll

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Adaptations to life on land

• Cuticle
• Waxy layer on aerial portion that prevents
  dessication
• Thickness depends on how dry the environment is

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Adaptations to life on land

• Cuticle
• Stomata
• Pores on the surface of leaves and stems
• Allows for gas exchange

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Adaptations to life on land

• Cuticle
• Stomata
• Gametangia
• Multicellular sex organs
• Covered by a layer of sterile cells protection
• Embryo develops inside gametangia

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Plant Life Cycle

• Alternation of generations
• Gametophyte
• Multicellular haploid stage
• Produces gametes
• Sporophyte
• Multicellular diploid stage
• Produces spores

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Gametophyte generation

• Gives rise to haploid gametes by mitosis
• Sperm cells form in antheridia
• Egg cells form in archegonia
• Once sperm cell fertilizes an egg cell, a zygote
  is formed

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Sporophyte generation

• Begins with diploid zygote
• Zygote divides by mitosis and develops into
  embryo
• Grows into mature sporophyte plant
• Specialized cells called sporogenous cells divide
  by meiosis into haploid spores

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Four Main Groups of Plants

• Bryophytes
• Seedless vascular plants
• Gymnosperms
• Angiosperms

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Bryophytes

• Nonvascular plants
• Rely on diffusion and osmosis
• Restricted in size
• Generally require moist environment
• MOSSES, LIVERWORTS, HORNWORTS

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Moss Life Cycle
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Vascular Plants

• Ferns, Gymnosperms, Angiosperms
• Contain xylem and phloem
• Cell walls contain lignin
• Strengthening polymer
• Support
• Conduction
• Allows plants to grow tall

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Seedless Vascular Plants

• Ferns club mosses
• Most important adaptation
• Xylem transports water
• Phloem transports food
• Transport allows plants to grow larger

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Club Mosses

• Only group of vascular plants with microphyll
• Leaf with single vascular strand
• True Roots
• Rhizome aerial stems
• Reproductive leaves with sporangia

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Ferns

• Rhizome w/ roots
• Fronds
• Sori found on fronds
• Clusters of sporangia
• Sporagenous cells undergo meiosis ? spores

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Fern Life Cycle
Prothallus
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Homospory vs. Heterospory

• Homospory sporophyte produces 1 kind of spore
• Heterospory microspores megaspores

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Dominant Stages

• Bryophyte Gametophyte
• Seedless Vascular Sporophyte
• Gymnosperms Sporophyte
• Angiosperms - Sporophyte