Plantae

1. Plantae Seed Plants

2. Vascular Plants • Formation of vascular tissue • Xylem (water) • Phloem (food) • True leaves, roots, and stems • Lignin • Sporophyte generation dominate

3. Alternation of Generation

4. Alternation of Generation • Sporophyte dependent on gametophyte • mosses • Large sporophyte and small independent gametophyte • ferns • Gametophyte dependent on sporophyte • seed plants

5. Why be Sporophyte Dominant? • Reduced mutations • UV light harmful to DNA • Diploid (2n) form copes better with mutations • two alleles

6. Why Retain Gametophyte Generation? • Ability to screen alleles • doesn’t require a large amount of energy • Sporophyte embryos rely on some gametophyte tissue

7. Seeds • A seed is a sporophyte in a package • spores are only single cells • packaged with food • All seed plants are heterosporous • megasporangia • microsporangia

8. From Ovule to Seed

9. Overview of Seed Plants • Produce Seeds • Can remain dormant for years • Pollination replaces swimming sperm • Gametophyte generation reduced • Gymnosperms lack antheridium • Angiosperms lack both archegonium and antheridium

10. Phylogeny

11. Gymnosperms(Naked Seed) • Division: Cycadophyta • Division: Ginkgophyta • Division: Gnetophyta • Division: Coniferophyta

12. Ginkgophyta • Ginkgo or Maidenhair Tree • Characteristic leaves • Only one species • Only males are planted

13. Cycadophyta • Cycads • Palm-like plants • Sago Palms • Leaves in cluster at top of trunks • True Secondary growth

14. Gnetophyta • 3 Genera • Ephedra • Mormon Tea • Ephedrine • raises heart rate • raises blood pressure

15. Coniferophyta

16. Coniferophyta • Pine tree is the sporophyte generation • Contains both male and female cones • Pollen (staminate) cones (low in tree) • produces pollen • Ovulate cones (high in tree) with scales • produces seeds

18. Pine Life Cycle • No Antheridium (microsporangia) produce pollen grain (4 cells) • 2 prothallial cells • 1 generative cell • become a sterile cell and a spermatogenous cell • produces 2 sperm • 1 tube cell • wings for dispersal

19. Pine Life Cycle • Ovule in a ovulate cone • integument (seed coat) (2n) • megasporangia (meiosis) or nucellus (nutrition) (2n) • produces 4 megaspores (3 die) • develops into female gametophyte • archegonium with eggs (n)

20. Angiosperms

21. Angiosperm

22. Sepals Petals Receptacle Stamen Anther Filament Carpel Stigma Style Ovary with ovule Flower

23. Angiosperm Life Cycle

24. Angiosperm Life Cycle • No Antheridium (microsporangia) • produce pollen grain • 1 generative cell • produces 2 sperm • 1 tube cell

25. Angiosperm Life Cycle • Ovule in Ovary • megasporangia • produces 4 megaspores (3 die) • develops into female gametophyte called the embryo sac

26. Angiosperm Life Cycle • Inside embryo sac • 7 cells (eight nuclei) due to 3 mitotic divisions • 3 antipodals • 2 polar nuclei (one cell) • 2 synergids • 1 egg

27. Angiosperm Life Cycle • Double fertilization • one sperm unites with egg • one sperm unites with polar nuclei • develops into endosperm (3n) • Fruit and Seed development • ovule = seed • ovary = fruit

28. Cross Pollination • Most flowers do not self-pollinate • stamen and carpal may develop at different times • stamen and carpal may be arranged in flower to avoid contact

29. Angiosperm Radiation • Begins the Cenozoic era (65 mya) • Most closely related to the Gnetophyta • Coevolution • the mutual influence of two species on each other • plants and animals (insects, birds, bats)

30. Pollination

31. Dispersal

32. The Global Impact • Transformed atmosphere • reduced carbon dioxide • cooled the earth • Nonrenewable resource