Seedless Plants – Whisk Ferns

1. Seedless Plants – Whisk Ferns

2. Seedless plants - Ferns • Most diverse of group • In tropics, grow very tall • Haploid spores produced in sporangia which form on special leaves of the sporophyte • Spores dispersed by wind • Give rise to tiny haploid gametophyte plants, which produce sperm and eggs • As in bryophytes, gametophytes lack conducting vessels and the sperm must swim through water

3. Fern Diversity

4. Fern Life Cycle: Woodwardia

5. Seed plants • Produce pollen and seeds • Pollen are tiny structures that carry sperm producing cells • Dispersed by wind of animal pollinators (i.e. bees) • Sperm travel through air to fertilize egg cells • Seeds consist of an embryonic plant, a supply of food for the embryo, and a protective outer seed coat • Can remain dormant until suitable habitat is available • Male gametophyte is the pollen grain • Female gametophyte produces the egg

6. 2 types of seed plants • Gymnosperms – lack flowers • Angiosperms – flowering plants

7. Seed plants - Gymnosperms • Evolved earlier than flowering plants • Were dominant until the rise of flowering plants • Most early species are now extinct • 4 phyla • Ginkgos • Cycads • Gnetophytes • Conifers

8. Seed plants – Gymnosperms - Ginkgos • Only 1 species survives Ginko biloba (maiden hair tree) • Either male or female • Female trees bear foul-smelling, fleshy seeds • Maintained by cultivation • More resistant to pollution than other trees • Leaves used as herbal remedy for improving memory

9. Seed plants – gymnospermsCycads • Found in tropical or subtropical climates • Large, finely divided leaves • Look similar to palms or large ferns • Most are approx. 3 feet tall

10. Seed plants – gymnospermsGnetophytes • Include approx. 70 species of shrubs, vines, and small trees • Genus Ephedra contains compound that is a stimulant and appetite suppressant • Reports of deaths • Welwitschia mirabilis – dry deserts of Africa • Deep taproot can extend up to 100 ft down into the soil • Has fibrous stem with only 2 leaves • Leaves never shed and continue to grow • Oldest plants are more than 200 yrs old

11. Gnetophytes Welwitschia mirabilis Ephedra

12. Seed plants – gymnospermsConifers • Still dominant plant • Species include pines, firs, spruce, hemlocks, cypresses • Most abundant in cold latitudes and high elevations • Adapted to cold, dry conditions • Retain green leaves, can continue photosynthesis • Leaves are thin needles covered with a thick, waterproof surface that minimizes evaporation • Produce “antifreeze” in their sap (gives piney scent) • Can continue transporting nutrients in below-freezing temperatures

13. Conifer Life Cycle: Ponderosa Pine

14. Seed plants - Angiosperms • Flowering plants • Dominate earth today • Over 260,000 species

15. 3 major adaptations of angiosperms • Flowers • Fruits • Broad leaves

16. Flowers • Both male and female gametes are formed • May have evolved when ancient gymnosperm developed relationships with animals (i.e. insects) that carried pollen from plant to plant

17. Flower Structure

18. Why fruits? • Ovary surrounding the seed matures into a fruit • Many fruits entice animals to disperse seeds • Some hitchhike on animals • Some fruits have special structures to aid dispersal (i.e. maple fruits form wings that carry seed)

19. Broad leaves

20. Life Cycle: Lilium

21. Flower Plants – 2 Groups • Monocots • 1 cotyledon • Dicots (Eudicots) • 2 cotyledon