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

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