Gymnosperms
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Transcript of Gymnosperms
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Gymnosperms
EQ: How do I describe the characteristics of gymnosperms?
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Gymnosperms
• A seed plant that produces naked seeds – not enclosed by any protective covering
• Most have needlelike or scale like leaves
• Most have deep growing root systems
EQ: How do I describe the
characteristics of gymnosperms?
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Types of Gymnosperms
• Oldest type of seed plant – appeared on Earth 360 million years ago
• Classified into four groups– Cycads– Ginkgo– Gnetophytes– Conifers
EQ: How do I describe the characteristics of gymnosperms?
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Cycads
• 175 million years ago the majority of plant on Earth were cycads
• Grows only in tropical areas now
• Looks like a palm tree with cones– Cone can grow to be as
large as a football– Seeds used to make flour
for flour tortillas
EQ: How do I describe the characteristics of gymnosperms?
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Ginkgo• Extremely old plant• Only one species
survives today– Chinese and
Japanese cared for this species in their gardens
• Used today to on city street. Very resilient to pollution from city traffic
EQ: How do I describe the characteristics of
gymnosperms?
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Gnetophytes
• Least likely to see
• Live in hot dry desserts of southern Africa and Western US as well as rain forests
EQ: How do I describe the characteristics of gymnosperms?
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Conifers
• Cone bearing plants
• Largest and most diverse gymnosperms
• Keep their needles year round
EQ: How do I describe the characteristics of gymnosperms?
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Reproduction
• Cones – reproductive structure for a gymnosperm
• Most gymnosperms produce two types of cones
EQ: How do I describe the
characteristics of gymnosperms?
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ReproductionMale cones– smaller than
female cones– produce pollen
that later become sperm
Female cones• Larger than male• Contain one ovule
at the base of each scale
• Ovule – structure that contains egg cell
EQ: How do I describe the characteristics of gymnosperms?
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Pollination• Transfer of pollen from a male
reproductive structure to a female reproductive structure– Wind often carries the pollen
• Pollen collects in the sticky substance produced by each ovule
• Scales of ovule close and trap pollen
• Seed develops on scale
EQ: How do I describe the characteristics of gymnosperms?
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Pollination• Female cones
stay on tree until seed matures
• Male cones fall off after they shed their pollen
EQ: How do I describe the characteristics of gymnosperms?
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Seed Dispersal• As seed
develops female cone increases in size
• Cones with immature seeds point upward
• Cones with mature seeds point downward
EQ: How do I describe the characteristics of gymnosperms?
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EQ: How do I describe the characteristics of gymnosperms?
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Class Work and Homework
• Fill In– What did I learn– Confused– Say
– Read pages A 150 – A 155– Questions 1-4, A 155
EQ: How do I describe the
characteristics of gymnosperms?