GYMNOSPERMS - THE NAKED SEEDS
General Characteristics: SPERMOPHYTA - seed plants
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BODY PLAN
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Dominant diploid sporophyte
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Have roots, stems, leaves, vascular tissue
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Leaves = large or needle like
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Have two types of cones
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ADVANTAGES
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DIVERSITY
CYCADS
GINKO
Produce spores  gametophyte
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CONIFER
The Male Cone
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Appears in the string
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Pollen Grain = immature male gametophyte
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Cells in the cone divide by meiosis and
produce small haploid spores  pollen
grains
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Pollen grains are released into the air
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Pollen grains
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Occurs deep within the protective tissues of the
parent sporophyte
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A sperm nucleus from the pollen grain unites with
the egg  zygote
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In Pine it takes 15 months from pollination to
fertilization
FEMALE CONES
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More familiar
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Larger spores form by meiosis = haploid egg
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Female gametophyte stay inside tissue of parent
sporophyte
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POLLINATION
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Pollen grain carried to female cone via wind
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DEVELOPMENT OF THE EMBRYO
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When it arrives inside the female cone, each pollen
grain forms a tiny pollen tube
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Zygote cells undergo mitosis  embryo 
sporophyte plant
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Embryo surrounded by food storage tissue (part of
gametophyte)
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Pollen Grain + Pollen Tube =
Mature male gametophyte
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Pollen tube grows into female gametophyte until it
reaches an egg
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Protective coat of sporophyte tissue develops
around embryo and food
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FERTILIZATION
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By the time the food runs out, embryo has
chlorophyll and can make its own