Plants

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Plants

• Chapters
• 22-25

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What is a Plant?

• Eukaryotic organism
• Multicellular
• Autotrophic

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Chloroplast

• Plants have chloroplast that carry out
  Photosynthesis
• Photosynthesis (uses sunlight as energy sourche)
  CO2 H20 -gt Glucose (C6H12O6) and O2
• Chloroplast are green pigment that reflects green
  light
• Has internal membrane that increases surface area

• What is the advantage to Photosynthesis/Autotroph
  
• Can make own food dont need to hunt of find

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• Plant cells have cell walls to add rigidity and
  protect the cell
• The cell walls are made of cellulose which we
  cannot digest
• Cellulose is a Carbohydrate

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Plant types

• Mosses
• They lack a vascular system and true roots
• Low growing plants that like to live near a water
  supply
• These evolved fists- why they are most primitive

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• Ferns
• Have roots and a vascular system
• Do not have seeds

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Roots

• The usually underground portion of a plant that
  lacks leaves
• serves as support
• draws minerals and water from the surrounding
  soil
• sometimes stores food
• Root hairs- provide increase surface area
• Roots are specialized for Mitosis why?

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What is vascular tissue?

• Tissue in the plant that transports water and
  nutrients
• Xylem transports water
• Phloem transports nutrients
• Transpiration water flows through the plant
  from root to leaf
• Released onto leaf undersurface through stomata
  and evaporates

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• How are roots and vascular tissue an adaptation
  allow plant to live in more arid conditions
• Grow to taller heights because can move water and
  nutrient by means other then diffusion

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Gymnosperms

• Cone bearers
• Seeds are exposed
• Called evergreens or conifers
• Remain green all year- why is this an advantage?
• Can perform photosynthesis all year

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Seeds

• A fertilized plant ovule containing an embryo.
• Why is this an adaptation sexual reproduction
  -gt increased genetic variation

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Germination

• Process by which plants emerge from seeds and
  begin growth
• Can lay dormant for long periods and wait on
  proper conditions
• Temperature
• Water
• Why is this advantageous?
• Best chance for survival

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Pine Needles

• The long, slender shape reduces leaf area, which,
  in turn, reduces the amount of water vapor
  escaping the leaf. (one time less surface are is
  an adaptation)
• Pine needles are shed year round just not all
  at one time.

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Angiosperms

• Flowering plants
• Seeds protected by a layer of tissue
• Flowers are the reproductive organs
• Ovaries surround and protect seed inside the
  flower
• Many times the ovaries will develop into fruit

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Flowers

• known as a bloom or blossom
• is the reproductive structure found in flowering
  plants
• The biological function of a flower is to effect
  reproduction, usually by providing a mechanism
  for the union of sperm with eggs.
• Increased by pollinators

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• Pollinators are attracted to flowers because of
  bright colors and they smell nice (same reason we
  like them)
• Spreads pollen (sperm) to other flowers
  increasing genetic variation

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Plant Reproduction

• Mostly sexual reproduction
• Some plants have a way of carrying out asexual
  reproduction

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• Pollen is the male gametes of plants
• Can be compared to sperm cells in animals
• Plants have ovules with eggs cells that can be
  fertilized by pollen
• The seed is an early embryo that can, in some
  cases remain dormant for long periods of time

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Covered seeds

• The seed coat protects the seed
• The endosperm (food supply) nourishes the embryo

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Seed protection

• Less likely to be eaten
• Protected from environment
• Nourishment for seed
• - better chance for survival

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Seed dispersal

• Seeds have different shapes or protective
  coverings to aid in their dispersal
• Adaptation move away from parent plant or other
  seedlings less competition

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Leaves

• Wide broad leaves provide additional surface area
  to absorb sunlight
• Increase photosynthesis
• However increase rate of water loss which could
  be bad- so how do plants over come this

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Adaptation to avoid water loss

• Cuticle waxy covering on leaves (lipids
  hydrophobic) keep water from entering or
  leaving
• Stomata openings in the bottom of the leaf that
  allow water to exit
• Has guard cells on both sides of stomata to open
  and close

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Specialized leaves for habitat

• Water lilies thick cuticle to keep water out
• Cacti Needles same as pine needles- reduce
  surface area (water loss) also provide
  protection
• Broad leaves- for areas of limited sunlight
  (rainforest floor)

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Can Plants Move?

• Plants cannot get up and walk like us, but they
  can move stems and leaves toward certain stimuli
• These movements are called tropisms

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Gravitropism

• Plant grows upward against the pull of gravity
• Allows seed to grow up out of soil
• Adaptation to get sunlight

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Phototropism

• Plant grows toward light source
• To get sunlight for photosynthesis

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Thigmotropism

• A plants response to touch
• Can be used as protection
• Can be used for stability
• Venus fly trap uses to obtain food(nutrients)

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Plant Hormones

• Important for growth and maturation
• Are chemical substances that control a plants
  patterns of growth and development
• Example Auxins role in phototropism

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• Auxin stimulates the elongation of cells
• When light hits the tip of a plant, more auxin is
  produced in the shaded area
• The dark side of the stem elongates causing the
  stem to bend toward the light

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Uses of plants

• Plants are a major food source for heterotrophs
• Where do plants get their energy?
• They are autotrophic and photosynthetic
• Photosynthesis produces Oxygen

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Other uses

• Oils
• Medicine
• Lumber
• Aesthetics
• Shelter for animals
• Commercial products