1. Plant Diversity
Chapter 29-30

3. Evolution Evolved from green algae ancestor Charophytes (green algae)
Closest plant relative
Over 470 million years ago

4. Evolution Similarities shared with algae Autotrophs
Multicellular eukaryotes
Cellulose in cell walls
Chlorophyll a and b

5. Red algae ANCESTRAL ALGA Chlorophytes Viridiplantae Charophytes
Fig. 29-4
Red algae
ANCESTRAL
ALGA
Chlorophytes
Viridiplantae
Charophytes
Figure 29.4 Three possible “plant” kingdoms
Streptophyta
Embryophytes
Plantae

6. Evolution Traits derived by plants 1. Embryophytes
Embryos develop in maternal tissues
2. Sporangia
Walled spores
3. Multicellular gametangia
4. Apical meristems

7. Evolution Move to land-less water Cuticle:
Waxy substance - protects water loss
Stomata (stoma-singular):
Opening in leaf
Gas exchange

8. Evolution Leaves Dominant diploid phase Shorter haploid stage
Yields greater photosynthesis surface
Dominant diploid phase
Shorter haploid stage
Structural support of vascular tissue

9. (a) Fossilized spores (b) Fossilized sporophyte tissue Fig. 29-6
Figure 29.6 Ancient plant spores and tissue (colorized SEMs)
(b) Fossilized
sporophyte tissue

10. Alternation of generations
Fig. 29-5a
Gamete from
another plant
Gametophyte
(n)
Mitosis
Mitosis n n n n
Spore
Gamete
MEIOSIS
FERTILIZATION
Zygote 2n
Figure 29.5 Derived traits of land plants
Mitosis
Sporophyte
(2n)
Alternation of generations

11. Apical meristem of shoot Developing leaves Apical meristems
Fig. 29-5e
Apical
meristem
of shoot
Developing
leaves
Apical meristems
Figure 29.5 Derived traits of land plants
Apical meristem
of root
Shoot
Root
100 µm
100 µm

12. Life cycles Alteration of generations Multicellular haploid & diploid
Brown, green & red algae have similar life cycle

13. Life cycle Gametophyte: “gamete plant” Haploid generation
Produce haploid gametes through mitosis
Fuse during fertilization (zygote)

14. Life cycle Sporophyte: ”spore plant” Diploid generation
Meiosis produces haploid spores
Leads to multicellular haploid gametophyte

15. Life cycle Sporangia Where meiosis takes place
Diploid produces 4 haploid spores
Multicellular haploid gametophyte

16. Life cycle Gametangia: Structures where gametes are produced Mosses
Large part of life cycle is haploid
Vascular plants gametophyte is much smaller

17. Alternation of generations
Fig. 29-5a
Gamete from
another plant
Gametophyte
(n)
Mitosis
Mitosis n n n n
Spore
Gamete
MEIOSIS
FERTILIZATION
Zygote 2n
Figure 29.5 Derived traits of land plants
Mitosis
Sporophyte
(2n)
Alternation of generations

19. Life cycle
Seed plants
Gametophyte are nutritionally dependent on the sporophytes
Gametophyte generation gets smaller
More specialized for land

20. Plant diversity Nonvascular plants: Lack vascular tissue
Contain water-conducting xylem
Food-conducting phloem
Stems, leaves and roots

21. Groups 1. Nonvascular land plants 2. Seedless vascular plants
Mosses, liverworts, hornworts
2. Seedless vascular plants
Club mosses
Ferns
3. Gymnosperms (naked seed)
4. Angiosperms (flowering plants)

22. Figure 29.7 Highlights of plant evolution1
Origin of land plants (about 475 mya) 2
Origin of vascular plants (about 420 mya) 3
Origin of extant seed plants (about 305 mya)
Liverworts
Nonvascular
plants
(bryophytes)
Land plants
ANCES-
TRAL
GREEN
ALGA 1
Hornworts
Mosses
Lycophytes (club mosses,
spike mosses, quillworts)
Seedless
vascular
plants 2
Vascular plants
Pterophytes (ferns,
horsetails, whisk ferns)
Figure 29.7 Highlights of plant evolution
Gymnosperms 3
Seed plants
Angiosperms
500
450
400
350
300 50
Millions of years ago (mya)

23. Table 29-1
Table 29.1

24. Liverworts, hornworts

25. Seedless vascular plants

26. Gymnosperms

27. Angiosperms

28. Nonvascular land plants
Usually small
Lack vascular tissue to carry water to aerial parts of the plant
Found in damp, shady habitats
Need water to reproduce sexually
Gametophytes are photosynthetic
More visible (green)
Sporophytes are attached to the gametophytes

29. Nonvascular land plants
Mosses (Bryophytes)
Rhizoids: “roots”
Cells to absorb water
“leaves”
Green, haploid, single cell layer thick
Most abundance in the tropics
Very sensitive to air pollution

30. Moss

32. Seedless vascular plants
Earliest form of vascular plants
Need external water for fertilization
No seeds
Sporophyte more complex
Both sporophyte & gametophyte are photosynthetic
Live independently

33. Ferns

35. Seed plants 425 million years ago Seeds gives the plant advantages
1. Protection of embryo by sporophyte
2. Easier to disperse
3. Dormant stage

36. Seed plants 2 kinds of gametophytes Male (pollen grains)
Female (ovule)
No need for external water
Sperm move to egg in a pollen tube

37. Gymnosperms Gymnos Greek for “naked” Sperma “with seed”
Lack flowers and fruit
Ovules are naked at time of pollination
Pines, firs, spruces, larches, yews, junipers, cedars, cypresses, and redwoods.

40. Angiosperms Flowering plants
Ovules are closed by diploid tissues at time of fertilization
Angeion means “vessel” in Greek
Sperma “seed”

41. Flower structure Receptacle: Where flower parts are attached Sepals:
Green leaf like
Protect the immature flower

42. Flower structure Petals: Colored, attract pollinators
Stamens (male gametophytes)
Anther: Pollen producing
Filament: a stalk
Carpels (female gametophytes)
Ovule(base), ovary, stigma and style (connects the stigma to the ovary)

43. Flower structure

44. Life cycle Pollination Pollen transfers to the stigma
Self-pollination or from another plant
Produce a germinating seed
Young sporophyte (diploid)

45. Life cycle

47. Benefits Food Rice, wheat, potatoes Coffee, tea, cocoa Medicines
Digitalis (heart med)
Morphine (pain relief)
Fuel
Wood