Transcript Gynosperms - leportebiologyhonors

Gynosperms
Gymnosperms
• 720 species
• “naked seed” seeds not enclosed in any
structure
• Cones called strobili
• Do NOT need water for sperm to reach eggnow covered to reduce water loss
• Pollen- enclosed sperm
Ginkgos- Ginkgophyta
• 1 species alive- Ginkgo biloba flourished
during age of dinosaurs
• Fan-shaped leaves
• Resistant to air-pollution, insects, disease,
highly planted in cities
• Seeds are thick and fleshy and produced on
female trees
Ginkgos
Figure 9.1: Ginkgo biloba (A) typical leaf; (B)
pollen-bearing strobilus; (C) paired ovules on
stalk at the point of pollination. Ovules
continue to develop and fertilization takes
place after ovules fall to the ground.
Ginkgos
Cycads- Cycadophyta
• 100 species alive- also flourished with
dinosaurs
• Male and female plants
• Leaves resemble a palm tree
• Large cones
• Several species facing extinction
Cycads
Cycads
Gnetophyta
• 3 genera
• One or two strap-shaped leaves that split as
the plant ages
• Ephedra- gives us the drug ephedrine
Ephedra
Conifers- Coniferophyta
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Pine trees
Produce true cones
Male cones are small, clustered and fleshy
Female cones are large and become woody
Leaves are needle-like