1. Today: What am I: Protistan Jeopardy! Plants, Part 1

2. Defining the “Plants” Land plants form a monophyletic group of embryophytes that evolved from the green algae

3. Within the “Plants” Seven major clades of Land Plants have vascular tissue (tracheids), the other three are nonvascular

4. What Challenges Does Life on Land Present?

5. Key Adaptations to Life on Land the Cuticle the Cuticle Gametangia to enclose and protect gametes Gametangia to enclose and protect gametes Embryos (enclosed, protected young plants Embryos (enclosed, protected young plants Pigments to protect from UV Pigments to protect from UV Spore walls from sporopollenin Spore walls from sporopollenin Mutualisitic associations with fungi Mutualisitic associations with fungi

6. Exploring Non-Vascular Plants Liverworts, hornworts, and mosses Liverworts, hornworts, and mosses Challenges to life without a vascular system?? Challenges to life without a vascular system??

7. Check Out the Moss Lifecycle!

8. Cool Things About Mosses

9. Other Seedless, Non-Vascular Plants Liverworts: probably most ancient sporophyteas are shorter and often simpler lots of asexual reproduction by fragmentation (gemmae cups for dispersal by raindrops!)

10. Other Seedless, Non-Vascular Plants Hornworts differ in: the Structure of the chloroplast (plate-like) having Stomata potential for indeterminate growth of sporophytes (until transport becomes limiting!)

11. Other Seedless, Non-Vascular Plants Mosses: far more abundant today utilize apical cell division specialized cell type (hydroid) provides water channels (but no lignin)

12. Exploring the Earliest Vascular Plants (Seedless)

13. Vascular Plant Evolution From their bryophyte-like ancestors, inherit: Tissue-producing meristems Tissue-producing meristems Gametangia Gametangia Embryos and the sporo- phytes that develop from them Embryos and the sporo- phytes that develop from them Stomata Stomata Cuticles Cuticles Sporopollenin-walled spores Sporopollenin-walled spores

14. Exploring the Earliest Vascular Plants (Seedless) Vascular plants have xylem (water and minerals; made primarily of tracheids) and phloem (to transport sugars) Vascular plants have xylem (water and minerals; made primarily of tracheids) and phloem (to transport sugars)

15. The Vascular Plants: Major Changes Have true vascular tissue (phloem and xylem) Have true vascular tissue (phloem and xylem) Dominant sporophyte generation Dominant sporophyte generation Branched sporophytes Branched sporophytes These early vascular plants are all seedless These early vascular plants are all seedless

16. A Fern Lifecycle What do you remember about this lifecycle??

17. The Gymnosperms “Naked Seeds” What’s new and exciting about the gymnosperms (conifers)?? What’s new and exciting about the gymnosperms (conifers)??

18. The Gymnosperms “Naked Seeds” 3 Major Adaptations: 1. Continued reduction of gametophyte 2. Evolution of the seed 3. Evolution of pollen Arabidopsis thaliana pollen grains Microscopy by Juergen Berger, computer image manipulation by Heiko SchoofJuergen Berger

19. 1. Reduction of the Gametophyte

20. 2. Evolution of the Seed SEED = sporophyte embryo packaged with a food supply in a protective coat. The fossilized remains of the Jeholornis prima, shown in an illustration, included about 50 well-preserved seeds in the bird's stomach. (CNN.com)

21. 2. Evolution of the Seed All seed plants are heterosporous! Megaspores (+ female gametophytes) retained within parent sporophyte!

22. OVULE OVULE (Integument + Megaporangium + Megaspore) After fertilization, the ovule develops into a SEED. 2. Evolution of the Seed

23. 3. Evolution of Pollen Microspores develop into pollen grains Pollen grains mature to become male gametophtyes Transfer of pollen to ovule = pollination Doesn’t require water!!

24. Gymnosperms Ovules and seeds develop of the surface of specialized leaves called sporophylls

25. Gymnosperm Evolution

26. Gymnosperm Diversity Four extant phyla: 1. Cycads 2. Ginkgos 3. Gnetophyta 4. Conifers Few species of tropical, palm-like trees Symbiotic with N-fixing bacteria Toxic to livestock!

27. Gymnosperm Diversity One remaining species! Popular ornamental (pollution resistant) Produces Gingko and stinky, fleshy seeds Four extant phyla: 1. Cycads 2. Ginkgos 3. Gnetophyta 4. Conifers

28. Gymnosperm Diversity 3 very different genera: Welwitschia, Gnetum, and Ephedra Four extant phyla: 1. Cycads 2. Ginkgos 3. Gnetophyta 4. Conifers

29. Government announces ban on ephedra Wednesday, December 31, 2003 Posted: 7:58 AM EST (1258 GMT) The debate over the safety of ephedra heated up after pitcher Steve Bechler died February 17.

30. Gymnosperm Diversity Largest group (pines firs, spruces, larches, yews, junipers, cedars, cypresses and redwoods) Mostly evergreen; dominant in N. hemisphere (where growing seasons are relatively short) Four extant phyla: 1. Cycads 2. Ginkgos 3. Gnetophyta 4. Conifers

32. Scale from an Ovulate Cone

33. Thought Question For You… Why to Conifers do so well here? Shouldn’t they be outcompeted by the angiosperms (flowering trees)??

34. Cool Coniferous Adaptations

35. Minor Modifications Both gymnosperms and angiosperms use tracheids in their xylem. Angiosperms also use vessel elements, and reinforce with fiber cells !

36. Major Modification: the Flower 4 circles of modified leaves: 1.Sepals (Calyx) 2.Petals (Corolla) 3.Stamens 4.Carpels

37. Hypothetical Origin of the Carpel

38. Describing Flowers Flowers may be complete (have all four basic organs) or incomplete (lacking one or more) The Magnolia, a complete flower! Photo: Daniel Mosquin

39. Plants may be monoecious (one house) or dioecious (two houses)

40. One Strategy…

41. Describing Flowers Flowers may be described as bilateral or radial.

42. Describing Flowers Flowers may be clustered together to form an inflorescence

43. Fruits are Mature Ovaries Fruits protect seeds and aid in their dispersal Ovary wall becomes the pericarp (thickened wall of the fruit )

44. Fruits are Mature Ovaries

45. Types of Fruit 1. Simple Fruit- derived from a single ovary 2. Aggregate Fruit- derived from a single flower with several carpels 3. Multiple Fruit- develops from a group of flowers tightly clustered together (inflorescence) 4. Accessory Fruits – develop from additional parts

46. Angiosperm Evolution and Diversity

47. The Angiosperms Evolution of the Flower! Traditional taxonomy = 2 Classes MonocotsandDicots Jack-in-the-Pulpit, Arisaema triphyllum

48. Not Monophyletic!

49. Angiosperm Lifecycles Like the Gymnosperms: Heterosporous Heterosporous Flower of the sporophyte produces microspores (will form male gametophytes) and megaspores (will form female gametophytes) Flower of the sporophyte produces microspores (will form male gametophytes) and megaspores (will form female gametophytes)

50. Angiosperm Lifecycles In Angiosperms, Each pollen grain has two haploid cells. Ovules develop within the ovary, contain the female gametophyte or embryo sac. (Even further reduction of gametophyte generation!)

52. Double

53. zygote SPOROPHYTE (2n) GAMETOPHYTE (n) GREEN ALGABRYOPHYTEFERNGYMNOSPERMANGIOSPERM Sporophyte Dominant: An Evolutionary Trend

54. Cross-Pollination Some flowers can self- pollinate, but most use diverse strategies to ensure cross-pollination

55. Angiosperms Shape Evolution By the end of the Cretaceous (65 mya) angiosperms are the dominant plants on Earth. Plants and their pollinators and dispersers are a good example of coevolution (mutual evolutionary influence)

56. Other Notes about Angiosperms - Ecologically important - Major human food source - Major human food source - Source of unique secondary compounds (drugs!) - Source of unique secondary compounds (drugs!) “Diversity is a non-renewable resource!”