CHAPTER 29 The Evolution of Seed Plants

1. CHAPTER 29The Evolution of Seed Plants

2. Chapter 29: The Evolution of Seed Plants General Characteristics of the Seed Plants The Gymnosperms: Naked Seeds The Angiosperms: Flowering Plants

3. General Characteristics of the Seed Plants • The seed plants are heterosporous and have greatly reduced gametophytes. Review Figures 29.1, 29.2 3

4. figure 29-01.jpg 29.1 Figure 29.1

5. figure 29-02a.jpg 29.2 – Part 1 Figure 29.2 – Part 1

6. figure 29-02b.jpg 29.2 – Part 2 Figure 29.2 – Part 2 Figure 29.2 – Part 2

7. General Characteristics of the Seed Plants • Most modern seed plants have no swimming gametes and do not require liquid water for fertilization. • The male gametophyte is dispersed by wind or animals. 7

8. General Characteristics of the Seed Plants • Theseed is a well-protected resting stage that often contains food that supports the growth of the embryo. 8

9. The Gymnosperms: Naked Seeds • The gymnosperms, once the dominant vegetation on Earth, still dominate forests in the northern parts of the Northern Hemisphere and at high elevations. • No flowers • Seeds not protected by fruit 9

10. The Gymnosperms: Naked Seeds • The four surviving gymnosperm phyla are the Cycadophyta, Ginkgophyta, Gnetophyta, and Coniferophyta. 10

11. The Gymnosperms: Naked Seeds • Modern gymnosperms all have abundant xylem and extensive secondary growth. 11

12. The Gymnosperms: Naked Seeds • Conifers have a life cycle in which naked seeds are produced on the scales of female cones. • Pollen cones are smaller than seed cones. • Pollen is transferred by wind. Review Figure 29.5 12

13. figure 29-05.jpg 29.5 Figure 29.5

14. The Angiosperms: Flowering Plants • Angiosperms are distinguished by double fertilization, as are the Gnetophyta. • Double fertilization results in a triploid nutritive tissue, the endosperm. Review Figure 29.10 14

15. figure 29-10.jpg 29.10 Figure 29.10

16. The Angiosperms: Flowering Plants • Angiosperms are characterized by the production of flowers and fruits. • Ovules and seeds are enclosed by a carpel. 16

17. The Angiosperms: Flowering Plants • The vascular tissues of angiosperms contain three characteristic cell types: • vessel elements • fibers • companion cells. 17

18. The Angiosperms: Flowering Plants • Flowers are made up of various combinations of carpels, stamens, petals, and sepals. • Perfect flowers have both carpels and stamens. Review Figure 29.6

19. figure 29-06.jpg 29.618 Figure 29.6

20. The Angiosperms: Flowering Plants • Monoecious plant species have both female and male flowers on one plant. • In dioecious species, male and female plants are separate. 20

21. The Angiosperms: Flowering Plants • Carpels and stamens may have evolved from leaflike structures. Review Figure 29.9 21

22. figure 29-09.jpg 29.9 Figure 29.9

23. The Angiosperms: Flowering Plants • Amborella, a tropical shrub, is the sole living representative of the first angiosperm lineage. 23

24. The Angiosperms: Flowering Plants • There are two major lineages of flowering plants: monocots and eudicots. Review Figure 29.13 24

25. figure 29-13.jpg 29.13 Figure 29.13

26. The Angiosperms: Flowering Plants • The evolutionary origin of the angiosperms remains a mystery. 26