Diversity of Plants

1. Diversity of Plants Chapter 22

2. Nonvascular Plants • Do not have vascular tissue • NV plants tissue = ~one cell thick • Water and nutrients travel through cells via osmosis and diffusion • SLOW • Live in moist habitats

3. Nonvascular Plants • Mosses Liverworts • Hornworts

4. Alternation of Generations • Diploid sporophyte • Haploid gametophyte (Dominant) • Sporophytes are physically attached to gametophytes and are dependent on them for nutrition

5. Sporophyte vs Gametophyte • Sporophyte: produces spores • Gametophyte (Dominant) • Produce antheridium: male reproductive structure • Sperm • Produce archegonium: female reproductive structure • Egg

6. Nonvascular Divisions • Bryophta: mosses • Rhizoids: help anchor stem to the soil • Grow in dense carpets of hundreds of plants • Grow anywhere where there is sufficient moisture • Most well known: peat moss • Gardeners use to increase water-holding ability in soil

7. Nonvascular Divisions • Hepatophyta: Liverworts • Flattened body shaped like a liver • ThalloseLiverworts • Leafy Liverworts • Rhizoids

8. Nonvascular Divisions • Anthocerophyta: hornworts • Sporophyte resembles the horn of an animal • Single large chloroplast in each cell

9. Non-Seed Vascular Plants • Vascular tissue: tubelike elongated cells that transport water and sugar • Xylem: transports water and nutrients • From roots to shoots (upward) • Phloem: transports sugars • Usually from shoots to roots (downward) but can move in an upward direction when needed

10. Alternation of Generations • Sporophyte (dominant) • Larger in size • Does not depend on gametophyte • Gametophyte • Stobilus: formed to protect reproductive cells • Prothallus: formed from stobilus, lives in or on the soil. • Antheridia and Archegonia form

11. Divisions of Non-Seed Vascular Plants • Lycophyta: club mosses and spike mosses • Has roots, stems and small leaves • Single vein of vascular tissue runs through each leaf

12. Divisions of Non-Seed Vascular Plants • Sphenophyta: horsetails • Contain silica that give them a rough texture • Usually grow about 1m tall • Most found in marshes, shallow ponds, steam banks, and other areas where there is damp soil • Stem is unique, jointed, at each joint a whorl of leaves

13. Divisions of Non-Seed Vascular Plants • Pterophyta: Ferns • Many species and very abundant • Can live in dry or moist environments • In most ferns the main stem is underground and is called a rhizome • First vascular plant to have leaves with branching veins of vascular tissue

14. Vascular Seed Plants • Introduction of pollen grain and ovule • Before in non-seed plants sperm has to swim through water to each the egg • No continuous film of water needed with seeds

15. Fertilization and Reproduction • Fertilization: union of the sperm and egg • After fertilization the zygote develops into an embyro • Embryos include cotyledons: tiny seed leaves that store or absorb food

16. Advantages of Seeds • Food supply within seed • Tough protective coating: seed coat • Adapted for easy dispersal

17. Diversity • Gymnosperms: produce seeds on scales of cones, “naked seed” • Angiosperms: flowering plants, produce seeds enclosed within a fruit

18. Gymnosperms • Cycadophyta • Separate male and female plants

19. Gymnosperms • Ginkgophyta • Separate male and female plants • One living species

20. Gymnosperms • Gentophyta • Three genera • Gnetum • Ephedra • Welwitscha

21. Gymnosperms • Coniferophyta • Male and Female cones on same plant