Gymnosperms

1. Gymnosperms A seed plant that produces “naked” seeds

2. What are gymnosperms? • Seed plants that produce seeds NOT enclosed in a protective fruit. • Many have needle-like leaves • Deep growing root systems • Oldest type of seed plant-giant sequoias

3. 4 groups of gymnosperms • Cycads • Conifers • Ginkgoes • Gnetophytes

4. Cycads • Grow mainly in tropical areas • Look like palm trees with cones

5. Conifers • Cone-bearing plants • Most are evergreens • Pine trees, junipers, sequoias • Largest, most diverse groups

6. Ginkgoes • Only one species lives today • Grew millions of years ago • Can tolerate air pollution-so planted along city streets

7. Gnetophytes • Live in hot deserts and tropical rain forest • Some are trees, others shrubs or vines

8. reproduction • Most involves CONES-covered with scales • Most gymnosperms produce male and female cones • Male cones produce pollen which contain cells that will become sperm cells. • Female cones contain ovules which contain the egg cell

9. Pollination • Transfer of pollen from the male reproductive structure to the female reproductive structure • Usually carried by wind • Collects on a sticky substance produced by the ovule

10. Fertilization • After pollination, the ovule will close and seal in the pollen. • The sperm cell fertilizes the egg cell • The fertilized egg (zygote) develops into the embryo • It can take up 2 years for the seed to mature

11. Germination • Once the seeds mature, the scales open • Wind shakes the seeds out and carries them away • If seeds land in favorable conditions, the seed will sprout--germinate

12. Useful products • Paper • Lumber • Rayon fibers • Cellophane wrap • Turpentine • Rosin • These are renewable resources!