LAND PLANTS AND THEIR EVOLUTION Chapter 19

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LAND PLANTS AND THEIR EVOLUTION Chapter 19

• Characteristics of Plants
• Multicellular autotrophs
• Cell wall of cellulose
• Food stored as starch
• Evolved from green algae
• Primarily terrestrial

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PROBLEMS OF LIFE ON LAND
PROBLEM SOLUTION
Obtain water Roots and root hairs
Transport water, food Xylem phloem
Prevent dessication Cutin, drop leaves, stomates
Gravity Cell walls, lignin, xylem
Obtain CO2 Stomates
Reproduce Pollensperm
Protect Embryo Seeds, Fruit
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Plant Kingdom

• Non Vascular Vascular
• Bryophytes Tracheophytes
• Mosses
• Liverworts

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BRYOPHYTES

• Mosses and Liverworts
• No vascular tissue (xylem and phloem)
• No true roots, stems, flowers or leaves
• Tiny!
• Water is required for fertilization
• Gametophyte generation is dominant.

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MOSS ANATOMY

• Antheridium Reproductive structure that makes
  sperm
• Archegonium Reproductive structure that makes
  eggs
• Protonema A filament that grows into a new plant

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ALTERNATION OF GENERATIONS

• GAMETOPHYTE plant generation that produces
  gametes
• SPOROPHYTE Plant generation that produces spores

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Plant Life Cycle

• ALTERNATION OF GENERATIONS

2N n Diploid haploid
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MOSS LIFE CYCLE Alternation of Generations
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Antheridia and Archegonia
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Figure 29.16x Moss life cycle
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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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MOSS PROTONEMA

• Haploid or diploid?

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Figure 29.16x Moss life cycle
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Figure 29.19 Sphagnum, or peat moss Peat bog in
Oneida County, Wisconsin (top), closeup of
Sphagnum (bottom left), Sphagnum "leaf" (bottom
right)
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Figure 29.19x A peat moss bog in Norway
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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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LIVERWORT THALLUS (LEAF-LIKE BODY)
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GEMMAE CUPS ASEXUAL REPRODUCTION
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Female liverworts with archegonia

• This is a female liverwort.

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Male liverworts with antheridia

• Gemmae cups

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What Sex are these liverworts?