Characteristics and Structures of Plants

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Characteristics and Structures of Plants

• SC Standards
• 6-2.3
• 6-2.4

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• Plants are classified into groups based on
  specific structures.
• Plants may be classified by
• Whether they circulate fluids (like rainwater)
  through their bodies (vascular) or need to absorb
  them from the moisture that surrounds them
  (nonvascular)
• How they reproduce
• Whether they produce seeds in cones or
  in flowers

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NONVASCULAR PLANTS

• Cannot circulate rainwater through their stems
  and leaves but must absorb it from the
  environment that surrounds them
• Do not have true roots, stems or leaves
• Usually small in size

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Nonvascular (cont.)

• Help prevent erosion by carpeting the forest
  floor
• Examples
• Mosses
• Liverworts
• hornworts

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VASCULAR PLANTS

• Largest group in the plant kingdom
• Have true roots, stems and leaves
• Stems can be either woody (trees) or herbaceous
  (grass, dandelions)
• Has tube-like structures that provide support and
  help circulate water and food throughout the plant

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VASCULAR OR NONVASCULAR?
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VASCULAR OR NONVASCULAR?
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SPORE-PRODUCING PLANT

• Plants that produce spores for reproduction
  instead of seeds
• Spores are much smaller than seeds
• Almost all flowerless plants produce spores
• Examples mosses and ferns

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SEED-PRODUCING PLANT

• Plants that reproduce through seeds
• From these seeds, new plants grow
• Two major groups
• Cone-bearing plants
• Flowering plants

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SPORE-PRODUCING OR SEED-PRODUCING?
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SPORE-PRODUCING OR SEED-PRODUCING?
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CONE-BEARING PLANTS(conifers)

• Largest and most diverse group of seed-producing
  plants
• Most are evergreen plants
• In addition to having cones, conifers are trees
  or shrubs that NEVER have flowers and that
  have needle-like leaves

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FLOWERING PLANTS

• These plants differ from a conifer because they
  grow their seeds inside an ovary which is
  embedded in a flower
• The flower then becomes a fruit containing the
  seeds
• Cotyledons- seed leaves that store food for the
  seed

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CONE-BEARING OR FLOWERING PLANT?
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CONE-BEARING OR FLOWERING PLANT?
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MONOCOT

• Seed leaves (cotyledons) with one storage area
• Flowers of monocots have either three petals or
  multiples of three
• Leaves are long and slender with veins that are
  parallel to each other

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Monocot (cont.)

• Vascular tube structures are scattered randomly
  throughout the stem
• Examples
• Grass
• Corn
• Rice
• Lilies
• tulips

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DICOT

• Seed leaves (cotyledons) with two food storage
  areas
• Flowers of dicots have either four or five petals
  or multiples of four or five
• The leaves are usually wide with veins that
  branch off each other

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Dicot (cont.)

• Vascular tube structures are arranged in circle
  within the stem
• Examples
• Roses
• Dandelions
• Maple tree
• Oak tree

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MONOCOT OR DICOT?
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MONOCOT OR DICOT?
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STRUCTURES OF PLANTS

• Flowering plants have special structures that
  function for defense, survival and reproduction

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DEFENSE

• THORNS? sharp outgrowths from the stems of plants
  that function in defending the plant from being
  eaten by some animals

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Defense (cont.)

• POISONS? chemical substances specifically
  designed to discourage animals from eating them
• Some make the animal sick
• Some kill the animal
• Others just taste badly so that they
  discourage the predator

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STRUCTURES FOR SURVIVAL

• LEAVES?
• site for food production
• Place where photosynthesis, respiration and
  transpiration takes place

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Structures for survival (cont.)

• STEMS?
• Support the plant and hold the leaves up to the
  light
• Transport water from roots to the leaves and
  other plant parts
• Transport food made in the leaves to growing
  parts of the plant
• Function as food storage sites

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Structures for survival (cont.)

• ROOTS?
• Anchor the plant in the ground
• Absorb water and nutrients from the soil and
  store extra food for the plants
• The more root space available, the more water and
  nutrients it can absorb
• Two types of root systems
• Fibrous
• taproots

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• Fibrous roots? consist of several main roots that
  branch off to form a mass of roots
• Example grass, corn and some trees
• Taproots? consists of one large, main root with
  smaller roots branching off
• Examples carrots, dandelions or cacti

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REPRODUCTIVE PARTS OF A PLANT

• Flowers? produce seeds
• ? many contain both female and male parts needed
  to produce new flowers
• ? flower petals are often colorful
  or have a scent
  to attract insects or
  other animals

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• STAMEN? male part of the flower
• ? contains an anther on a stalk
• ? anther produces pollen
• PISTIL? female part of the flower
• ? contains the ovary (contains the egg cells),
  stigma (the sticky top where pollen grains land)
  and style (a stalk down which
  the pollen tube grows
  after pollination has taken
  place)

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• SEEDS?
• Fertilized ovules from which new plants are
  formed
• Fruit that is formed from the ovary protects them