Chapter 29: Plant Diversity

1. Admit Slip 3. List 3 words you think of when you look at the picture/diagram 2. Write 2 ideas you have based on the picture and your words. If possible, use your words as you write your ideas. 1. Write 1 question you have. Chapter 29: Plant Diversity How plants colonized land Chapter 29.1

2. Plants supply oxygen and are the ultimate provider of most of the food eaten or absorbed by other organisms.

3. Terminology • -phyte=Plant • Bryo=moss • Ptero=fern • Gymno=naked • Mitosis: division of cells-forms identical copy with full set of chromosomes (2n), body cells • Meiosis: division of cells-forms a cell with a half set of chromosomes (n), sex cells • Haploid: half the total chromosomes for an organism (egg/sperm) • Diploid: full number of chromosomes for an organims (somatic)

4. What problems do terrestrial habitats offer for plants????

5. Land plants evolved from green algae • Evolved from Charophytes (green algae) more than 500 million years ago. • Evidence for evolution from Charophytes • Both produce cellulose for cell walls the same way • Their peroxisomes have enzymes that reduce effects of photorespiration (unique to both) • Both produce cell plates the same way during cell division • Structure of sperm is closely related • Nuclear and chloroplast genetic evidence suggests close relation

6. Charophytes Chara Spirogyra Coleochaete

7. Problems of life on land

8. Problems of life on land

9. Movement of plants from sea to land • Advantages: • Increased sunlight (unfiltered by water) • More carbon dioxide in atmosphere than water • Soils rich in nutrients • Fewer predators • Challenges • Lack of water • Desiccation • Lack of structural support against gravity

10. Adaptations of Land Plants • Adaptations in growth • apical meristem: localized region of cell division at tips of roots and shoots • Adaptations in reproduction • alternation of generations • walled spores: protect spores in harsh environments • multicellular gametangia: structures for gamete production • multicellular dependent embryos: transfer of nutrients from tissue to embryo • Adaptations against water loss • Cuticle

11. Alteration of Generations • All land plants have two multicellular stages • Gametophyte • plant cells are haploid • Gametes are produced • Sporophyte • plant cells are diploid • Divides mitotically • Sporophyte produces spores through meiosis

12. Alteration of Generations During fertilization: gametes (egg and sperm-both haploid) fuse to form a diploid zygote (sporophyte) Zygote develops in tissues of female parent getting nutrients from it, sometimes called an embryophyte

13. Gametangia • Plants produce gametes in multicellular structures called gametangia • Female: archegonia-produces a single egg • Male: antheridia-produces many sperm

14. Chapter 29: Plant Diversity How plants colonized land Chapter 29.2

15. Bryophytes • Moss • Nonvasular (small size) • Seedless • Life cycle dominated by gametophyte stage • Water required for sperm to swim to the egg during fertilization

16. Bryophyte life cycle

18. Chapter 29: Plant Diversity How plants colonized land Chapter 29.3

19. Pteridophytes/Ferns • First plants with vascular tissue • Allowed plants to grow tall and gain access to sunlight • Seedless • Require film of water for sperm to reach egg • Life cycle dominated by the sporophyte stage • Meiosis occurs in sporangia producing haploid sporeswhich may grow into gametophytes with anteridia (release sperm) and achegonium (produce egg, house zygote after fertilization)

20. Pteridophytes/Ferns life cycle

21. Evolution of land plants