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Gymnosperms

Gymnosperms

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Gymnosperms

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  1. Gymnosperms Biology 11

  2. KINGDOM PLANTAE Vascular Plants Phylum Tracheophyta Seeds No Seeds Seeds enclosed Seeds ‘naked’ Ferns Phylum Cycadophyta (cycads) Ginkgophyta (ginkgo) Gnetophyta (shrubs, vines, tuberous root) Coniferophyta (cone-bearing tree)

  3. Seed Plants • Protective covering around embryo (seed) • Produce cones with seeds on cone scales • Seed develops on each scale of cone • Seed is not covered therefore naked • Gymnosperms: “naked seed” • Seeds arenot enclosed by a fruit (ovary)

  4. Reproduction occurs without water • Improved conducting tissue: thicker and stronger xylem. Became taller • Large, branching root system

  5. Adaptations for life on land • Gametophytes are reduced in size, often staying within the parent sporophyte • Swimming sperm are replaced with pollen which is dispersed by wind and insects • Produce seeds

  6. Seed Plants Vascular

  7. Cycadophyta- The cycads • Resemble palm trees but are cone bearing • Have fleshy stems and leathery, featherlike leaves • Motile sperm that swim to egg in ovule

  8. Ginkgophyta- The Ginkgos • Primitive tree • Dioecious: has separate male and female trees • Leaves are fan shaped and thick with leathery veins • Have motile sperm that swim to the egg in the ovule

  9. Gnetophyta- the gnetophytes • Can be found as shrubs, vines, or massive squat stems • Have sperm with no flagella • Pollen is transported to ovule (egg) by insects or wind

  10. Coniferophyta- the conifers • Conifers – cone bearers (separate male and female cones) • Many are evergreen and keep their leaves in the winter • Can grow very large and to old ages

  11. Redwood forests

  12. Are adapted to severe climates and conserving water with leaves, called needles, that are covered with waxy cuticles and are long, sharp, and tend to be flat • Have sperm withno flagella • Pollen is transported to ovule (egg) by insects or wind

  13. Reproduction • There are 2 types of cones: • Male cone (Pollen cone) • Produces pollen grains (male gametophyte) • Female cone (Seed cone) • Have female gametophyte that produces ovules (eggs)

  14. Some species of conifers have male and female cones on the same tree, others have separate trees with male and female cones

  15. A female cone lives and grows for several years, becoming much larger than a male cone. • An ovule develops on each scale of a female cone.  • Inside the ovule, an egg cell is produced.  • Male cones produce pollen (male gametophyte) MALE CONES (with pollen) FEMALE CONE With ovules

  16. If fertilization occurs, an embryo grows inside the ovule.  The ovule hardens, becoming a seed. • Eventually the scales spread, allowing the seeds to fall.  • If conditions are favourable where it falls, the embryo inside the pine seed will grow into a new tree. • Growing Sporophyte called A seedling

  17. Reproductive Cycle • Alternation of generations