1. Evolution of Seed Plants
Plant Diversity:
Evolution of Seed Plants

2. Previously:

3. Now:

4. First important change - Vascularization
-addition of cells joined to form tubes within the plant

5. First important change - Vascularization
-addition of cells joined to form tubes within the plant
phloem
Vascular bundle
xylem

6. First important change - Vascularization
-addition of cells joined to form tubes within the plant
Phloem – transports sugar and other nutrients
Xylem – transports water and minerals from roots

7. First important change - Vascularization
-addition of cells joined to form tubes within the plant
Xylem cells - lignified
Lignin

8. First important change - Vascularization
-addition of cells joined to form tubes within the plant
Lignin – provides support – allows plants to grow taller

9. Second important change: seeds

10. LIFE ON LAND – TERRESTRIAL ADAPTATIONS
- Seeds
- Reduced gametophytes
- Heterospory
- Ovules
- Pollen

11. Second important change: seeds

13. Why have reduced gametophytes
ovule
Protection from UV and
desiccation
Pine cone
(=female gametophyte)
Nutrients from sporophyte

14. Heterospory Microsporangia  microspores  male gametophyte
Megasporangia  megaspores  female gametophyte

15. OVULES
Megasporangium + megaspore + integument (developed from sporophyte) = OVULE

16. POLLEN
Microspore  pollen grain
Pollen wall
Male gamete

17. Advantages of pollen
1) Outer coat (Pollen wall) protects microspore
2) Permits wide range dispersal by wind, animals

18. Advantages of seeds
1) Outer coat protects sporophyte embryo
2) Supply of food – allows long term dormancy

20. GYMNOSPERMS
Cycads

21. GYMNOSPERMS
Ginkos

22. GYMNOSPERMS
Conifers

23. Gymnosperm Life Cycle

24. ANGIOSPERMS – FLOWERING PLANTS
-distinguished by being able to produce flowers and fruits

25. ANGIOSPERMS – FLOWERING PLANTS
Flower Structure – four rings of modified leaves
Carpel
Pistil
Style
Stamen
Ovary
Filament
Petals
Anther
Sepals

26. ANGIOSPERMS – FLOWERING PLANTS
Fruits – mature ovary of an angiosperm
- as seeds develop – wall of ovary thickens
e.g. pea pods
Ovary wall
ovule

27. Kinds of Fruits
Simple – single ovary (one to several seeds)
-fleshy or dry
Pomes
Drupes
Fleshy
Berries
Dry
Nuts

28. Kinds of Fruits (continued)
2. Aggregate – single flower with many ovaries
Blackberries
Raspberries
3. Multiple fruits - fused ovaries of multiple flowers
Pineapple

29. ANGIOSPERM LIFE CYCLE

30. CLASSIFICATION OF ANGIOSPERMS
Monocotyledonous
(“monocots”)
Dicotyledonous
(“dicots”)

31. Summary - Derived Traits of Seed Plants