EVOLUTION OF SEED PLANTS

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CHAPTER 30

• EVOLUTION OF SEED PLANTS

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• REPRODUCTIVE ADAPTATIONS
• GAMETOPHYTE OF THE SEED PLANTS DEVELOP WITHIN
  CASES OF SPORES RETAINED WITHIN THE TISSUE OF THE
  PARENT SPOROPHYTE
• SEED REPLACES THE SPORE AS THE MAIN MEANS TO
  DISPERSE OFFSPRING
• POLLEN BECAME THE VEHICLE FOR SPERM IN SEEDED
  PLANTS. POLLEN GRAIN IS AN IMMATURE MALE
  GAMETOPHYTE

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• GYMNOSPERMS (NAKED SEEDS)
• FOUR DIVISIONS
• CYCADOPHYTA
• GINKGOPHYTA
• GNETOPHYTA
• CONIFEROPHYTA

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• CYCADOPHYTA
• CYCADS RESEMBLE PALMS
• SOMETIMES KNOWN AS SAGE PALMS

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• GINKGOPHYTA
• AKA GINKGO
• HEARTY PLANTS
• HAVE THE ABILITY TO SURVIVE POLLUTION
• POPULAR ORNAMENT TREE

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• GNETOPHYTA
• ONLY FOUND IN SOUTHWEST AFRICA
• DESERT BIOMES
• LARGEST KNOW LEAVES

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• CONIFEROPHYTA
• PINES, FIRS AND REDWOODS
• CONE BEARING
• GIANT SEQUOIA, REDWOODS

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• PINE LIFE CYCLE
• PINE TREES ARE SPOROPHYTES. THE SPORANGIA ARE
  LOCATED ON SCALE LIKE SPOROPHYLLS THAT ARE
  DENSELY PACKED IN STRUCTURES KNOWN AS CONES
• HETEROSPOROUS
• TREES USUALLY CONTAIN BOTH MALE AND FEMALE CONES

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• ANGIOSPERMS
• MOST DIVERSE AND WIDESPREAD OF ALL PLANTS
• 250,000 SPECIES AS OPPOSED TO 700 GYMNOSPERMS
• ALL ARE IN A SINGLE DIVISION
• ANTHOPHYTA
• MONOCOTYLEDONS
• DICOTYLEDONS

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• VASCULAR TISSUE
• TRACHEIDS CELLS THAT CONDUCT WATER, EARLY FORM
  OF XYLEM
• XYLEM IS REINFORCED BY LIGNIN WITHIN THE CELL WALL

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• FLOWER
• REPRODUCTIVE STRUCTURE
• SEPALS GREEN, PROTECTIVE
• PETALS BRIGHT COLORS THAT ATTRACT INSECTS AND
  OTHER ANIMALS
• SEPALS AND PETALS ARE NOT DIRECTLY INVOLVED IN
  REPRODUCTION

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• REPRODUCTIVE ORGANS
• STAMEN MALE
• FILAMENT STALK
• ANTHER SAC THAT PRODUCES AND STORES POLLEN
• CARPLE (PISTIL) FEMALE
• STIGMA
• STYLE
• OVARY

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• FRUITS
• MATURE OVARIES
• PROTECT DORMANT SEEDS
• AIDES IN SEED DISPERSAL

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• LIFE CYCLE OF AN ANGIOSPERM
• HETEROSPOROUS
• POLLEN GRAINS, ARE IMMATURE MALE GAMETOPHYTES
  THAT MATURE IN THE ANTHER
• OVULES DEVELOP WITHIN THE OVARY AND CONAIN
  FEMALE GAMETOPHYTES, WHICH ARE FOUND IN THE
  EMBRYO SAC

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• DOUBLE FERTILIZATION
• BOTH SPERM WILL FERTILIZE CELLS WITHIN THE EMBRYO
  SAC
• UNIQUE CHARACTERISTIC OF ANGIOSPERMS

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• ANGIOSPERMS
• MARKED THE TRANSITION FROM THE MESOZOIDC TO
  CENOZOIC ERA
• TWO THEORIES
• 1. PUNCTUATED EQUILIBRIUM ANGIOSPERMS ABRUBTLY
  EVOLVED
• 2. GRADUALISM GRADUAL CHANGE OVER TIME

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• AGRICULTURE
• ANGIOSPERMS PROVIDE ALMOST ALL OF OUR FOOD
• FRUIT, VEGETABLES AND GRAINS
• FIBER
• MEDICATIONS, PERFUME AND DECORATIONS
• HUMANS HAVE INFLUENCED EVOLUTION BY ARTIFICIALLY
  SELECTING PLANTS FOR QUALITY AND QUANTITY. THIS
  MAY EFFECT THE GENE POOL OF CERTAIN PLANT SPECIES

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• PLANT DIVERSITY
• HABITAT DESTRUCTION NEW HOMES ETC.
• NON RENEWABLE RESOURCE
• ECOSYSTEMS REGENERATE SLOWLY
• HUMANS DEPEND ON PLANTS FOR VARIOUS REASONS, WE
  MUST THINK BEFORE WE DESTROY THEM