1. The Wonderful World of Green Plant Diversity and Evolution Biol 366 Spring 2014

2. Tree of Life: The Big Picture EukaryotesArchaeaBacteria ca. 4 bya now >3.5 bya >2 bya membrane-bound nucleus, organelles, etc.

3. Fig. 1.1 from Simpson

4. Green plants share: Chlorophylls a (ancestral) and b Starch storage Stellate flagellar structure Certain gene transfers from the chloroplast to the nucleus And other features (see Ch. 3)

5. Green plant diversity: Ca. 350,000 species Two major groups: 1) chlorophytes (marine and other green algae) and 2) streptophytes [freshwater green algae and embryophytes (= land plants)] A major branch (clade) in the eukaryotic Tree of Life

6. Fig. 3.1 from Simpson

7. Some definitions Clade = branch on an evolutionary tree, a lineage, includes an ancestor and all its descendants. Ex.: Green plants, chlorophytes, land plants. Paraphyletic group = a group that includes an ancestor and some (but not all) of its descendants, indicated by double quotation marks. Ex.: “Green algae”

8. Chlorophytes

9. Fig. 3.1 from Simpson

10. Basal streptophytes desmids Spirogyra Chara Nitella (Judd et al. 2008)

11. Conjugation in Spirogyra Haplontic life cycle (haploid dominant or zygotic meiosis) The only diploid cell Is the zygote zygote (2n) haploid body

12. biology.unm.edu mason.gmu.edu Charales Haplontic but some have multicellular gametangia (gamete-producing structures) ♀ ♂

13. Generalized charophyte life cycle: Alternation of generations X X gametangia gametophyte

14. Embryophytes (land plants) share: Cuticle Alternation of generations (multicellular sporophyte and multicellular gametophyte) Multicellular gametangia (gamete-producing structures) Multicellular sporangium (spore-producing structure) Embryo (young sporophyte) Parenchyma? (more likely ancestral)

15. Generalized embryophyte life cycle: Alternation of generations

16. Bryophytes Hornworts, liverworts, mosses Gametophyte-dominant No vascular tissue (except conducting cells in a few mosses) Separate male and female gametophytes Sperm must swim to the egg, therefore need water for fertilization and therefore must remain small

17. hornworts liverworts mosses

18. Plant Tree of Life: Embryophtes Tracheophytes (vascular plants) Hornworts Liverworts ca. 450 mya now Mosses “Bryophytes”

19. Liverwort gametophyte

20. Liverwort thallus showing air pores

21. Liverwort Multicellular gametangia (male = antheridia)

22. Liverwort Multicellular gametangia (female = archegonia) Oogamy Retention of zygote within the female gametophyte Multicellular embryo

23. Hornworts G S

24. Moss male gametangia (= antheridia) Capsule = sporangium of the sporophyte

25. Generalized embryophyte life cycle: Alternation of generations

26. Tracheophytes (vascular plants) Vascular tissue (tracheids) present Include lycophytes (quillworts, clubmosses, spikemosses), monilophytes (ferns, horsetails, whisk ferns), and spermatophytes (seed plants)

27. Fig. 4.1 from Simpson

28. Lycophytes & Monilophytes Quillworts, clubmosses & spikemosses (= lycophytes); ferns, whisk-ferns, & horsetails (= monilophytes); Independent gametophytes and sporophytes Sperm must still swim to the egg Most are homosporous; a few evolved heterospory Many homosporous ferns have means of avoiding self-fertilization

29. Lycophytes Selaginella (spikemoss) Lycopodium and friends (clubmosses) Isoetes (quillwort)

30. Whisk-fern (Psilotum) Ferns (Leptosporangia) Monilophytes (ferns, horsetails, whisk ferns) horsetails

31. 1n 2n 1n spores gametophyte sporophyte Nutritionally independent sporophytes and gametophytes

32. Fern Life Cycle, Fig. 4.32, Simpson

33. Lignophytes (woody plants) & Spermatophytes (seed plants) Secondary xylem (wood) & bark, heterospory, seeds, eustele, pollen (also pollen tube, pollination droplet) Includes gymnosperms and angiosperms

34. Fig. 5.1 from Simpson

35. Gymnosperms Conifers, gingko, cycads, Gnetales Molecular data support this group as having a single common ancestor No obvious defining character (see characters for Lignophytes & Spermatophytes)

36. Female cone with each scale bearing usually two ovules; directly exposed to pollen Male cones with each scale bearing two or more microsporangia

37. biology.ualberta.edu pine pollen pine microsporangia male female

38. Fig. 5.7 from Simpson

39. Angiosperms “Dicotyledons”, monocotyledons Heterosporous (ancestral) Sporophyte-dominant (ancestral) Pollen = male gametophyte (ancestral) Archegonia lost; embryo sac = female gametophyte; ovules enclosed in carpels (indirect pollination) Double fertilization produces zygote + primary endosperm nucleus

40. Flower = a short, determinate shoot bearing highly modified leaves, some of which are fertile (i.e., bearing either microsporangia or megasporangia), with the megasporangia in carpels

41. Animal pollination syndromes

42. Wind pollination

43. A wide range of fruit types…

44. Fig. 5.7 from Simpson

45. http://www.mun.ca/biology/scarr/Angiospermae.html

46. over 300,000 species of angiosperms The wonderful world of land plant diversity