1. Kingdom Plantae Bryophyta: Nonvascular Plants
Lycophyta, Sphenophyta, Pterophyta: Seedless Vascular Plants
Gymnosperms: Coniferophyta

2. Setting the Stage for Plants
Earth’s atmosphere was originally oxygen free
Ultraviolet radiation bombarded the surface
Photosynthetic cells produced oxygen and allowed formation of a protective ozone layer

3. Invading the Land
Cyanobacteria were probably the first to spread into and up freshwater streams
Later, green algae and fungi made the journey together
Every plant is descended from species of green algae

4. The Plant Kingdom Nearly all are multicelled
Vast majority are photoautotrophs
Energy from sun
Carbon dioxide from air
Minerals dissolved in water

5. zygophytes, related groups
Evolutionary Tree for Plants
flowering plants
green
algae
zygophytes, related groups
charophytes
bryophytes
lycophytes
horsetails
ferns
cycads
ginkgos
conifers
gnetophytes
seed plants
euphyllophytes
embryophytes (land plants)
vascular plants
(closely related groups)
Figure 23.3 Page 387

6. Nonvascular Plants Bryophytes Fewer than 19,000 species Three groups
Liverworts
Hornworts
Mosses

7. Vascular Plants Majority of plants
Have internal tissues that carry water and solutes
Two groups
Seedless vascular plants
Seed-bearing vascular plants

8. Seedless Vascular Plants
Arose during the Devonian
Produce spores but no seeds
Four main groups
Whisk ferns
Lycophytes
Horsetails
Ferns

9. Seed-Bearing Vascular Plants
Gymnosperms arose first
Cycads
Ginkgos
Gnetophytes
Conifers
Angiosperms arose later
Monocots
Dicots

10. Evolutionary Trend zygote SPOROPHYTE (2n) GAMETOPHYTE (n) GREEN ALGA
BRYOPHYTE
FERN
GYMNOSPERM
ANGIOSPERM

11. Adaptations to Land Root systems Shoot systems Vascular tissues
Waxy cuticle

12. Traits of Seed-Bearing Plants
Pollen grains
Arise from megaspores
Develop into male gametophytes
Can be transported without water
Seeds
Embryo sporophyte inside nutritive tissues and a protective coat
Can withstand hostile conditions

13. Bryophytes Small, nonvascular, nonwooody
Gametophyte dominates life cycle; has leaflike, stemlike, and rootlike parts
Usually live in wet habitats
Flagellated sperm require water to reach eggs

14. Moss Life Cycle
Zygote grows, develops into a sporophyte while still attached to gametophyte.
mature sporophyte
zygote
Diploid Stage
Fertilization
Meiosis
Haploid Stage
Spores germinate.
sperm-producing structure
male gametophyte
egg-producing structure
female gametophyte
Figure 23.5 Page 388

15. Phylum Bryophyta “Mosses”
The gametophyte of mosses consists of a leafy shoot that is anchored to the substrate by branched multicellular rhizoids.

16. Leaf arrangement is normally spiralled.

17. The initial stage of gametophyte development, resulting from germination of the spore,

18. is a filamentous branched structure known as the protonema.

19. Moss, highly branched with sporophytes terminating lateral branches.

20. Antheridia are equally elongated with a long narrow stalk

21. General morphology are seen in Sphagnum

22. Sporophyte

23. Habit shot of female shoots with terminal sporophytes and male shoots with clusters of orange antheridia surrounded by leaves. Copyright by Alan Heilman (Univ. Tenn.).

24. Close-up of gametophyte with orange antheridia (right) and sporophyte (left).

26. Marchantia: A Liverwort
Do not post on Internet
Reproduces asexually by gemmae
Gametophytes are male or female
Female gametophyte
Figure Page 389

27. Seedless Vascular Plants
Lycophytes (Lycophyta)
Whisk ferns (Psilophyta)
Horsetails (Sphenophyta)
Ferns (Pterophyta)

28. Ferns (Pterophyta) 12,000 species, mostly tropical
Most common sporophyte structure
Perennial underground stem (rhizome)
Roots and fronds arise from rhizome
Young fronds are coiled “fiddleheads”
Mature fronds divided into leaflets
Spores form on lower surface of some fronds

29. Phylum Pterophyta “ferns”

30. Pattern of uncoiling “fiddle heads”.

31. young “Fronds”

33. Fern Life Cycle Sporophyte still attached to gametophyte sorus zygote
rhizome
Diploid Stage
fertilization
meiosis
Haploid Stage
Spores
are
released
Spores develop
egg
sperm
mature
gametophyte
Spore germinates

34. On the back (abaxial) side of the frond occur the spore-producing structures called sori (singular sorus).

35. The sori are covered by a thin structure called an indusium.

36. Male (left)  Bisexual (Right)
Prothallus (gametophyte)

37. On the underside (ventral) of the prothallus, archegonia are frequently clustered around the apical notch as evidenced by the protruding archegonial necks seen in this SEM photo (by Joan Nester-Hudson).

38. Biflagellated sperm

39. At the moment of fertilization, the nuclei of sperm and egg fuse and a diploid zygote is formed. This begins the sporophytic generation again. The zygote divides mitotically to form and embryo and eventually a tiny sporophytic plant. These can often be seen still attached to the notch area of the prothallus.

41. Division Lycophyta “Club Mosses”

42. The sporophyte is relatively simple with dichotomously to pseudomonopodally branched green stems and spirally arranged microphylls (simple leaves with single veins).

43. Typically, the shoot system is separated into upright aerial shoots and morphologically distinct creeping rhizomes from which adventitious roots arise.

44. Sporangia are positioned on the adaxial side of specialized leaves that in turn are arranged in zones along the stem or in a terminal series, known as strobili

45. Division Sphenophyta “Horsetails or Scouring Rushes”

46. The sporophyte of Equisetum is differentiated into an underground rhizome that bears adventitious roots and an upright, photosynthetic stem with whorls of microphylls. The stem is jointed, i.e., the nodes are clearly defined by whorls of leaves.

47. Species in the subgenus Equisetum produce abundant branches that arise in whorls at the nodes.

48. The eusporangia of Equisetum are aggregated in terminal branched units known as strobili.

49. Strobili

51. Thousands of rounded spores are produced in each sporangium

52. Antheridia and biflagellated spermatozoids

54. Division Coniferophyta “Conifers”

55. Cluster of microsporangiate strobili of Pinus resinosa

56. Longitudinal section through a microsporangiate cone of pine consisting of microsporophylls spirally arranged around the central axis bearing microsporophylls.

58. Male gametophyte: pollen grain

59. Cross section of a pine needle