1. Chapter 30: Plant Diversity II: The Evolution of Seed Plants

2. Seed Plants Gymnosperms – naked seeds Angiosperms – covered seeds These two groups are the dominant plants on Earth today.

4. Adaptations: Seed Plants Gametophytes are even more reduced. Seeds replaced spores as the means for dispersal. Pollen is the vehicle for sperm cells.

5. Life Cycle switch

6. Gymnosperms - Divisions Coniferophyta - Conifers Cycadophyta - Cycads Ginkgophyta - Ginkgo Gnetophyta - Gnetae ~700 species

7. Characteristics Seeds with multiple seed leaves. Cones (strobili). Xylem with tracheids only. No flowers or fruits.

8. Life Cycle Most are heterosporous. Male gametophyte = pollen grain. Multi-cellular female gametophyte still produces archegonia.

11. Conifers Two types of cones  Pollen cone - male  Ovulate cone - female

12. Pollen Cone Male Cones Sporangia

13. Pollen Cone Sporangia with pollen Male Gametophyte or Pollen

14. Pollination Transfer of pollen from one individual to another. Usually accomplished by the wind for most Gymnosperms.

15. Ovulate Cone At time of Pollination Ovulate Cone

16. Megaspore Mature Cones

17. Conifers Fertilization Fusion of sperm and egg to produce a zygote. Pollination and fertilization may be separated by 1 year.

18. Conifer Seeds Embryo Mature Seed

19. Importances Coniferophyta:  Lumber  Paper  Resins

20. Importances  Food  Landscaping  Christmas trees

21. Other Examples Cypress Pacific Yew

22. Importances Cycadophyta:  Landscaping  Food

23. Ginkgo Ginkgophyta:  1 species extant  Living fossil

24. Ginkgo Tree Fall Color

25. Ginkgo - Male Male cones Sperm

26. Ginkgo - Female Female cones Mature cones

27. Importances Landscaping Drug Seeds (?)

28. Importances Gnetophyta:  "Mixed bag" of species  Various importances Ephedra

29. Other Gnetophyta Welwitschia Gnetum

30. Angiosperms Division - Anthophyta Most dominant plant group on land. Two main classes:  Monocotyledones (Monocots)  Dicotyledones (Dicots) ~235,000 species

31. Characteristics Have seeds, flowers and fruits.

32. Characteristics Xylem may have vessels.

33. Life History Male gametophyte reduced to a 2-3 celled pollen grain. Female gametophyte reduced to an embryo sac. Double fertilization.

35. Importances Food Lumber Medicines Landscaping Fibers

36. Importances Rubber Flower Industry Dyes Spices Soil Erosion Control

37. Angiosperms Main group for study of plants in future lessons.

38. Summary Know the adaptations of seed plants. Know examples, life cycles, and importances of the gymnosperms and angiosperms.