Introduction to Plants

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Introduction to Plants
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The First Plants

• The earliest photosynthetic organisms were
  plant-like protists.
• Even today about 70 of photosynthesis occurs in
  the oceans.

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Non-vascular Plants

• The earliest land plants were non-vascular
  plants.
• Non-vascular plants have no system of vessels to
  carry nutrients, water or waste.
• These mosses, liverworts, and hornworts evolved
  about 500 mya from green algae.

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Non-vascular Plant Reproduction

• They need a moist surface for gametes to swim
  together for reproduction.
• Non-vascular plants lack true leaves, roots or
  stems.
• All water, nutrients and waste move between cells
  by osmosis and diffusion. Their growth is
  limited.

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Plant Adaptations to Land

• The major adaptations to life on land included
• 1. Protection from drying out leaves and stems.

2. A system of vessels to transport water,
nutrients and wastes the roots, stems and
leaves. 3. A system to hold the plant up and
capture energy from light the stem and leaves.
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Vascular Plants - Ferns

• As plants adapted to land they evolved more
  complex structures.
• Ferns were the first vascular plants.
• Ferns have vascular tissue or vessels that
  transport materials between different parts of
  the plant.

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• Ferns have true roots to anchor them and absorb
  water and minerals.
• Fern leaves are photosynthetic and absorb gases
  from the atmosphere.

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Plants with Seeds

• Next plants evolved to have seeds, an
  evolutionary adaptation to improve reproductive
  success.
• Seeds allow a plant to reproduce sexually without
  needing water for the gametes to swim to each
  other.

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Gymnosperms

• Gymnosperms are plants that produce naked
  seeds.
• Gymnosperms include all the conifers or pine
  trees that produce cones.

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Angiosperms

• The most recent evolutionary adaptation for
  plants was to produce flowers, again to improve
  reproductive success.
• Angiosperms are flowering plants.

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Parts of a Flower
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Monocots and Dicots

• The seeds of angiosperms are protected in the
  body of a fruit, which develops from the ovary .
• There are two classes of angiosperms - monocots
  and dicots.
• Monocots have one seed leaf and dicots have two
  seed leaves.
• There are numerous differences between monocots
  and dicots.

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Compare Seed leaves

• Monocot one Dicot two

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Compare Veins

• Monocot parallel Dicot network

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Compare Vascular Bundles

• Monocot scattered Dicot ring pattern

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Compare Flower Parts

• Monocot threes Dicot 4s or 5s

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Compare Roots

• Monocot fibrous Dicot tap root