1. Plant Diversity 1: The Colonization of Land
Plant Unit
Plant Diversity 1: The Colonization of Land

2. The Colonization of Land
An Overview of Plant Evolution
Structural, chemical, and reproductive adaptations enabled plants to colonize land
The history of terrestrial adaptation is the key to modern plant diversity
The Origin of Plants
Plants probably evolved from green algae called charophytes
Alternation of generations in plants may have originated by delayed meiosis
Adaptations to shallow water preadapted plants for living on land

3. The Colonization of Land
Bryophytes
The embryophyte adaptation evolved into bryophytes
The gametophyte is the dominant generation I the life cycle of bryophytes
The three divisions of bryophytes are mosses, liverworts, and hornworts
The Origin of Vascular Plants
Additional terrestrial adaptations evolved as vascular plants descended from bryophyte-like anscestors
The branched sporophytes of vascular plants amplified the production of spores and made complex bodies possible
Seedless Vascular Plants
A sporophyte-dominant life-cycle evolved in seedless vascular plants
The three divisions of seedless vascular plants are lycophytes, horsetails, and ferns
Seedless vascular plants formed vast “coal forests” during the carboniferous period

6. Chara

7. Coleochaete

8. Charophyceans

9. Apical Meristems

10. Marchantia Embryo

11. Embryos of Land Plants

12. Alternation of Generation

13. Fern Spore

14. Hornwort
Sporangium

15. Archegonium
Antheridium
Gametangia

16. Cuticle

17. Polypodium Stem

18. Phloem and Xylem

19. Fossil Spores and Tissue

20. Plant Alternation of Generation Hypothesis

22. Thalloid Liverwort, Leafy Liverwort,
[Bryophyte collage]
Thalloid Liverwort, Leafy Liverwort,
Hornwort and Moss

23. Quillwort

24. Polytrichum Life-
Cycle

25. Gametophytes

26. Archegonium

27. Sporophytes

28. Sporangium

29. Spores

30. Protonemata

31. Moss Life Cycle

32. Sporophyte Section

33. Moss Sporangium

34. Peat Moss Bog

35. Sphagnum Moss

36. Sphagnum Leaf

37. Pteridophytes: Club Moss, Whisk Fern, Horsetail, Polypodium Fern

38. Lycophyte

39. Leaf Evolution Hypothesis

40. Fern Life Cycle

41. Mature Fern

42. Sorus

43. Sporgangium

44. Mature Sporangium

45. Germinating Spore

46. Gametophyte

47. Archegonia

48. Sporophytes

49. Polypodium Fern

50. Polypodium Sori

51. Polypodium Sorus

52. Carboniferous (replica)

55. The Colonization of Land
An Overview of Plant Evolution
Structural, chemical, and reproductive adaptations enabled plants to colonize land
The history of terrestrial adaptation is the key to modern plant diversity
The Origin of Plants
Plants probably evolved from green algae called charophytes
Alternation of generations in plants may have originated by delayed meiosis
Adaptations to shallow water preadapted plants for living on land

56. The Colonization of Land
Bryophytes
The embryophyte adaptation evolved into bryophytes
The gametophyte is the dominant generation I the life cycle of bryophytes
The three divisions of bryophytes are mosses, liverworts, and hornworts
The Origin of Vascular Plants
Additional terrestrial adaptations evolved as vascular plants descended from bryophyte-like anscestors
The branched sporophytes of vascular plants amplified the production of spores and made complex bodies possible
Seedless Vascular Plants
A sporophyte-dominant life-cycle evolved in seedless vascular plants
The three divisions of seedless vascular plants are lycophytes, horsetails, and ferns
Seedless vascular plants formed vast “coal forests” during the carboniferous period