How Did Plants Evolve?

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How Did Plants Evolve?
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• Scientists believe that plants evolved from an
  ancestor of green algae (a member of Kingdom
  Protista).
• These early plants were similar to todays mosses
  (shown through fossil evidence)
• Were dependent on water for reproduction and to
  avoid drying out.

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The Move To Land

• The advantage of life on land
• More sunlight
• More CO2
• More nutrients
• The disadvantage?
• Water Loss/Drying Out!
• So, what adaptations did plants develop in order
  to thrive on land?

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Adaptations

• 1 The Cuticle
• A waxy covering that prevents water loss
• 2 Vascular Tissue
• Not every part of a plant is touching water, so
  tubes transport materials up and down.
• Xylem Water up from the roots
• Phloem Sugars down from the leaves.
• 3 Seeds Instead of Spores
• Spores need water to reproduce
• Seeds provide an embryo with the food and
  protection needed for a dry environment.

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The Plant Family Tree
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The Bryophytes (Seedless Non-Vascular Plants)

• Cuticle?
• Yes
• Vascular Tissue?
• No
• SoStays close to the ground, near water
• Seeds?
• No
• Soreproduces with spores, must be near water
• Examples?
• Mosses
• Liverworts
• Hornworts

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Life Cycle of Moss
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The Plant Family Tree
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The Ferns (Seedless Vascular Plants)

• Cuticle?
• Yes
• Vascular Tissue?
• Yes
• Seeds?
• No
• Soreproduces with spores, must be near water
• Examples?
• Ferns
• Horsetail
• Equisetum

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Life Cycle of Fern
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The Plant Family Tree
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The Gymnosperms (Vascular Seed Plants)

• Cuticle?
• Yes
• Vascular Tissue?
• Yes (but leaves are reduced to needles to prevent
  water loss)
• Seeds?
• Yes
• Butthey are naked!
• Males Female Cones
• Examples?
• Pine
• Spruce
• Gingko

Male Female cone
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Gymnosperm Life cycle
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The Plant Family Tree
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The Angiosperms (Vascular Seed Plants)

• Cuticle?
• Yes
• Vascular Tissue?
• Yes
• Seeds?
• Yes
• Flowers fruit protect and help disperse!
• Examples?
• Flowering Plants
• Grass
• Corn

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Task you need to find a way to survive with your
feet permanently anchored in cement

• You CANT
• Hide from
• predators
• Seek a mate
• Walk to water or
• food
• Change your
• habitat

• You HAVE to
• Get necessary nutrients
• Get water oxygen
• Reproduce (your mate
• may be miles away)
• Deal with changes in your
• environment (i.e. dry, wet,
• hot, cold, dark, light, etc..)