3.2 The Plants

1. 3.2 The Plants Pages 86-87

2. Importance • Supply food through photosynthesis • Provide shelter and nesting sites • Products include paper, medicines, wood, clothing

3. Challenges • Habitat destruction • Pollution • Invasive species • Climate change

4. 4 types • Bryophytes-non vascular plants • Pteridophytes-seedless vascular plants • Gymosperms-cone bearing • Angiosperms-flowering plants

5. Characteristics • Multicellular • Eukaryotic cells • Photosynthetic • Cell walls contain cellulose • Sessile • Incredible diversity

6. Alternation of generations • Diploid (2n) produces spores, Haploid (n) produces gametes.

7. Adaptions for life on land • waxy cuticle (prevents water loss) • stomata (tiny pores for air and water vapour exchange)

8. Bryophytes • Mosses, liverworts and hornworts

9. Bryophytes • Example: sphagnum moss • cuticle and stomata • no vascular tissue or true leaves, roots or seeds • Wet conditions for reproduction • Antheridia (sperm), Archegonia (eggs) • Sporangium produce haploid spores • Gemmae (n) for asexual reproduction

10. Lycophytes and Pterophytes: The ferns

11. Lycophytes and Pterophytes • Lycophytes-club mosses • Pterophytes-ferns

12. Lycophytes and Pterophytes • Vascular tissue (xylem and phloem) • Lignin in cell walls (rigidity) • Seedless • Example: horsetails • Rhizomes (stems) • Fronds (leaves)

13. Angiosperms and Gymnosperms • Pollen- waterproof capsules, male gametophyte • Ovule-female gametophyte • Fertilization produces a seed (2n) • 70% of all human food comes from the seeds of corn, rice and wheat

14. Gymnosperms • Conifers • Cones • Examples: pine, spruce, cedar, juniper

15. Angiosperms • Flowering plants • Flowers (reproductive organs) • Fruit (ovary and outer tissues) • Cotyledon (store foods)