Lab 5 Origin Of Plants


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  • Lab 5 Origin Of Plants

    1. 1. Origin of Plants 1.) No Quiz 2.) Lab report due next week, turn in graphs now 3.) Lecture on Plant diversity (have diversity terms handout ready) 4.) Cladistics exercise -- turn in worksheet 5.) Lab practical next week – study plant diversity slides on bioviewer & names of phyla, orders, etc.
    2. 2. Principal Biological Concepts <ul><li>A. Charophytes as probable ancestors to terrestrial plants. </li></ul><ul><li>B. Terrestrial adaptations. </li></ul><ul><li>C. Alternation of generations. </li></ul><ul><li>D. Archegonia/ antheridia. </li></ul><ul><li>E. Vascular tissues. </li></ul><ul><li>F. Seeds. </li></ul><ul><li>G. Characters and synapomorphies of plant clades </li></ul>
    3. 3. Cyanobacteria
    4. 4. Marine life was already diverse (~550 Ma) before the rise of the land plants (~450 Ma) why didn’t plants evolve earlier and colonize the land?
    5. 5. CO2 today is ~380 ppm Why?
    6. 6. CO2 today is ~380 ppm Cyanobacteria -- 2.7 billion 1 st land plants 425 million yrs ago
    7. 7. Paleozoic = 542 to 251 million years ago
    8. 8.
    9. 9. Million years of evolution: Plant adaptations? Kingdom PLANTAE Land Plants (embryophytes)
    10. 10. Million years of evolution: Plant adaptations? Adaptations to land
    11. 11. Adaptations to terrestrial existence <ul><li>1. Support - rigid tissues, weight no longer borne by water. </li></ul><ul><li>2. Water transport and conservation - need to protect against desiccation. </li></ul><ul><li>Characteristics... </li></ul><ul><ul><li>a. vascular tissues - xylem and phloem </li></ul></ul><ul><ul><li>b. apical meristems </li></ul></ul><ul><ul><li>stems, roots, leaves - </li></ul></ul><ul><ul><li>with vascular tissues (except Bryophytes) </li></ul></ul><ul><ul><li>d. waxy cuticle </li></ul></ul><ul><ul><li>e. stomata in leaves </li></ul></ul>
    12. 12. Kingdom Chlorophyta Photosynthetic life moves onto land – What did this look like? <ul><li>Non-vascular plants </li></ul><ul><li>Vascular Plants (no seeds) </li></ul><ul><li>Vascular seed Plants </li></ul><ul><li>Flowering Plants </li></ul>Liverworts Hornworts Mosses Lycophytes Horsetails Ferns Cycads Ginkgo Conifers Gnetum Angiosperms Green Algae Next week
    13. 13. One of the most important events in the history of the Earth: The complete plant colonization to the land Occurred between the Ordovivian – Silurian ~450 – 440 Ma Cooksonia – now extinct
    14. 14. Cooksonia – now extinct
    15. 15. 10 m tall!! Early land plants did not have roots – formed symbiotic associations with fungi from 420 mya
    16. 17. Kingdom Chlorophyta <ul><li>Chlorophytes </li></ul><ul><li>(Ancestors to vascular plants.) </li></ul><ul><ul><li>1. Starch as a storage product - deposited within chloroplasts. </li></ul></ul><ul><ul><li>2. Have chlorophyll a and b , and carotenoids. </li></ul></ul><ul><ul><li>3. Cell wall of cellulose . </li></ul></ul><ul><ul><li>4. Similar chloroplast structure - thylakoids stacked as grana. </li></ul></ul>
    17. 18. Kingdom Chlorophyta <ul><li>Non-vascular plants </li></ul><ul><li>Vascular Plants (no seeds) </li></ul><ul><li>Vascular seed Plants </li></ul><ul><li>Flowering Plants </li></ul>Liverworts Hornworts Mosses Lycophytes Horsetails Ferns Cycads Ginkgo Conifers Gnetum Angiosperms Green Algae
    18. 19. Phylum CHLOROPHYTA - green algae <ul><li>1. Mostly freshwater, some marine. </li></ul><ul><li>2. About 7,000 species. </li></ul><ul><li>3. Wide diversity of forms </li></ul><ul><ul><li>a. Single celled </li></ul></ul><ul><ul><li>b. Filamentous </li></ul></ul><ul><ul><li>c. Sheets, aggregates, colonies </li></ul></ul><ul><ul><li>d. True multicellularity </li></ul></ul><ul><li>4. Sexual and asexual reproduction. </li></ul><ul><li>5. Not important commercially. </li></ul><ul><li>7. In lab: </li></ul><ul><ul><li>a. Volvox (no. 19-1) </li></ul></ul><ul><ul><li>b. Ulva - wet </li></ul></ul><ul><ul><li>c. Acetabularia - wet </li></ul></ul>Volvox
    19. 20. Phylum CHAROPHYTA - Charophyceans or stoneworts <ul><li>Distinct from other Chlorophytes and </li></ul><ul><li>are thought to be most closely related </li></ul><ul><li>to true plants. </li></ul><ul><li>Differentiated from other green algae by ultrastructural differences in cell plate </li></ul><ul><li>formation during cell division. </li></ul><ul><li>Charophytes form a &quot; phragmoplast &quot; - a perpendicular orientation of the spindle </li></ul><ul><li>relative to the cell wall. This feature is </li></ul><ul><li>common to all land plants. </li></ul><ul><li>3. In lab: Spirogyra (no. 19-2) and Chara </li></ul>
    20. 21. Within charophyceans there is increase in body complexity that is thought to have given risen to early land plants
    21. 22. Spirogyra - conjugating alga
    22. 23. Charophyceans: Chara (top) Coleochaete: orbicularis (bottom)
    23. 24. Kingdom PLANTAE Land Plants (embryophytes) <ul><li>4 groups </li></ul><ul><ul><li>1. Bryophytes - non-vascular plants </li></ul></ul><ul><ul><li>2. Pteridophytes - non-seeded vascular plants </li></ul></ul><ul><ul><li>3. Gymnosperms - seeded vascular plants </li></ul></ul><ul><ul><li>4. Angiosperms - flowering plants </li></ul></ul>
    24. 25. Kingdom Chlorophyta <ul><li>Non-vascular plants </li></ul><ul><li>Vascular Plants (no seeds) </li></ul><ul><li>Vascular seed Plants </li></ul><ul><li>Flowering Plants </li></ul>Liverworts Hornworts Mosses Lycophytes Horsetails Ferns Cycads Ginkgo Conifers Gnetum Angiosperms Green Algae
    25. 26. <ul><li>Some definitions: </li></ul><ul><li>Gametophyte: gametophyte is the multicellular structure, or phase, that is haploid, containing a single set of chromosomes. The gametophyte produces male or female gametes (or both), by a process of cell division called mitosis </li></ul><ul><li>Sporophyte: the plant in which meiosis occurs and produces spores </li></ul><ul><li>Monoecious: male and female gametes produced on the same plant </li></ul><ul><li>Dioecious: male and female gametes produced on separate plants </li></ul><ul><li>Antheridia: the male sperm-bearing organ </li></ul><ul><li>Archegonia: the female egg-bearing organ </li></ul>
    26. 27. Gametangia: Archegonium of Marchantia (left) Antheridium of a hornwort (right)
    27. 28. Alternation of generations Diploid Haploid
    28. 29. Alternation of generations <ul><li>1. Alternation between sporophyte (spore-producing) and gametophyte (gamete-producing), diploid and haploid . </li></ul><ul><li>2. Transitions of generations marked by meiosis and syngamy (fertilization) . </li></ul><ul><li>3. Evolutionarily important - haploid genes in plant gametophytes are transcribed (unlike those in animals). Gives the possibility of rapid selection. </li></ul>
    29. 30. Land plants: Apical meristems of shoots and roots shoots roots
    30. 31. &quot; BRYOPHYTES &quot; - non-vascular land plants <ul><li>A. Gametophyte dominant – sporophyte reduced </li></ul><ul><li>B. Often with separate sexes ( dioecious ). </li></ul><ul><li>C. Antheridia - produce flagellated sperm. </li></ul><ul><li>D. Archegonia - produce egg and house developing embryo (sporophyte). </li></ul><ul><li>E. Antheridia and archegonia, or modifications thereof, are found in all early plant groups (through ferns). </li></ul><ul><li>F. Water required for sperm transfer. Sperm are flagellated (i.e., motile). This is true of all primitive plants. </li></ul>Hornwort Liverwort Moss Moss
    31. 32. Kingdom Chlorophyta <ul><li>Non-vascular plants </li></ul><ul><li>Vascular Plants (no seeds) </li></ul><ul><li>Vascular seed Plants </li></ul><ul><li>Flowering Plants </li></ul>Liverworts Hornworts Mosses Lycophytes Horsetails Ferns Cycads Ginkgo Conifers Gnetum Angiosperms Green Algae
    32. 33. Two phyla <ul><li>1. Phylum Hepatophyta - liverworts </li></ul><ul><ul><li>a. antheridia and archegonia borne on gametangiophores - antheridiophores and archegoniophores , respectively. </li></ul></ul><ul><ul><li>asexual reproduction with gemmae cups . </li></ul></ul><ul><li>2. Phylum Bryophyta - mosses </li></ul><ul><li>NO VASCULAR TISSUE - therefore - small size (limits of diffusion), moist habitats, close to ground. </li></ul>
    33. 34. Liverworts Liverworts Marchantia polymorpha Gemmae cups Archegoniophore Antheridiophore Asexual
    34. 35. The life cycle of Polytrichum, a moss Diploid Haploid
    35. 36. Moss life cycle
    36. 37. VASCULAR PLANTS &quot;TRACHEOPHYTES&quot; <ul><li>A. Vascular tissues </li></ul><ul><ul><li>1. Xylem </li></ul></ul><ul><ul><ul><li>a. transport of water and dissolved minerals. </li></ul></ul></ul><ul><ul><ul><li>b. tracheids and vessel elements - lignified, spiral thickenings of cell wall - dead at maturity. </li></ul></ul></ul><ul><ul><ul><li>c. also provide support for the plant body. </li></ul></ul></ul><ul><ul><li>2. Phloem </li></ul></ul><ul><ul><ul><li>a. transport of photosynthate (product of photosynthesis). </li></ul></ul></ul><ul><ul><ul><li>b. sieve-tube cells - elongate, tapered with sieve area in cell plate, living. </li></ul></ul></ul><ul><ul><ul><li>c. companion cell - controls movement of food through seive tubes. </li></ul></ul></ul><ul><li>B. Sporophyte dominant - gametophyte becomes increasingly diminutive. </li></ul>
    37. 38. Kingdom Chlorophyta <ul><li>Non-vascular plants </li></ul><ul><li>Vascular Plants (no seeds) </li></ul><ul><li>Vascular seed Plants </li></ul><ul><li>Flowering Plants </li></ul>Liverworts Hornworts Mosses Lycophytes Horsetails Ferns Cycads Ginkgo Conifers Gnetum Angiosperms Green Algae
    38. 39. SEEDLESS VASCULAR PLANTS Lycophyte (top left), whisk fern (top right), horsetail (bottom left), fern (bottom right)
    39. 40. Phylum LYCOPHYTA - club mosses and quillworts <ul><li>1. True stems, roots, and leaves. </li></ul><ul><li>2. Leaves are small and scalelike with traces of vascular tissue = microphylls . </li></ul><ul><li>3 . Strobilus = cluster of sporophylls (specialized leaves bearing sporangia ), at tips of branches ( Lycopodium ) or along branches ( Selaginella ). </li></ul><ul><li>4. Free-living gametophyte. </li></ul>
    40. 41. Lycophyte
    41. 42. Lepidodendron - Ancient Lycopds (club mosses)
    42. 43. Phylum PTEROPHYTA ferns and fern allies <ul><li>1. Whisk ferns ( Psilotum ) </li></ul><ul><ul><li>a. Well developed xylem and phloem in stem. </li></ul></ul><ul><ul><li>b. No true roots or leaves - secondarily lost . </li></ul></ul><ul><ul><li>c. Rhizome (underground stem - absorptive) with rhizoids and with myccorhizae. </li></ul></ul><ul><ul><li>d. Sporangia borne on shoots - unique character. </li></ul></ul><ul><ul><li>e. Gametophytes are free-living, nonphotosynthetic, saprophytes with associated mycorrhizae. </li></ul></ul>
    43. 44. Psilotum nudum
    44. 45. Horsetails ( Equisetum ) <ul><li>a. Ribbed, jointed (nodes) stems with silica crystals = &quot;scouring rushes.&quot; </li></ul><ul><li>b. Leaves are non-photosynthetic microphylls . </li></ul><ul><li>c. Underground rhizomes - asexual reproduction. </li></ul><ul><li>d. True roots. </li></ul><ul><li>e. Terminal strobili on reproductive shoots. </li></ul><ul><li>f. Equisetum is only living genus. </li></ul>
    45. 46. Horsetails
    46. 47. This is how a forest of Calamites and Asteroxylon may have appeared just about anywhere on the Earth 390 million years ago. The Calamites are the slender &quot;Christmas tree&quot; shaped plants. They grew as tall as many of today's conifers, though they are the ancestors of the much smaller modern horsetails. The  snake-like curlicue plants in the foreground are the now-extinct Asteroxylon, which emerged at the beginning of the Devonian period about 417 million years ago
    47. 48. Ferns <ul><li>a. Sporophyte dominant but dependent on gametophyte at first. </li></ul><ul><li>b. Independent (free-living, photosynthetic) gametophyte ( prothallus or prothallium ) - without vascular tissues. Has antheridia and archegonia. </li></ul><ul><li>c. True roots and stems (underground rhizomes) and leaves (megaphylls called fronds ). </li></ul><ul><li>d. Sporangia clustered in sori , often protected by indusium . </li></ul><ul><li>e. In lab: </li></ul><ul><ul><li>i. Cyrtomium (no. 5) </li></ul></ul><ul><ul><li>ii. fern prothalium (no. 6) </li></ul></ul><ul><ul><li>iii. fern sporophyte (no. 7) </li></ul></ul><ul><ul><li>iv. live fern </li></ul></ul>
    48. 49. The life cycle of a fern Haploid Diploid Homosporous (mostly)
    49. 50. Fern sporophyll, a leaf specialized for spore production Indusium
    50. 51. Life cycle of a fern: mature sporangium
    51. 52. Fern gametophyte
    52. 53. Fern archegonia
    53. 54. Fern sporophytes growing out of fertilized gametophytes
    54. 55. Mature fern sporophyte – produces spores
    55. 56. Ferns
    56. 57. Carboniferous forest – ferns abundant
    57. 58. SEED PLANTS &quot; SPERMATOPHYTES &quot; <ul><li>A. Seed = plant embryo protected by integument (“seed coat”). </li></ul><ul><li>B. &quot;GYMNOSPERMS&quot; - &quot;naked seeds&quot;- seeds without protection of ovary. </li></ul><ul><li>C. Sporophyte dominant - gametophyte reduced to very small size. </li></ul><ul><ul><li>1. Megagametophyte - multicellular archegonium. </li></ul></ul><ul><ul><li>2 . Microgametophyte - pollen grains - 3 or 4 cells. No antheridia. </li></ul></ul><ul><ul><li>3. “Mega” and “micro” are used in higher plants to denote the larger female structures and the smaller male ones. </li></ul></ul>
    58. 59. Kingdom Chlorophyta <ul><li>Non-vascular plants </li></ul><ul><li>Vascular Plants (no seeds) </li></ul><ul><li>Vascular seed Plants </li></ul><ul><li>Flowering Plants </li></ul>Liverworts Hornworts Mosses Lycophytes Horsetails Ferns Cycads Ginkgo Conifers Gnetum Angiosperms Green Algae
    59. 60. Seed fossil
    60. 61. From ovule to seed
    61. 62. Phylum GINKGOPHYTA ginkgo <ul><li>A. Only one species living ( Ginkgo biloba ). Common ornamental - tolerant of pollution. </li></ul><ul><li>B. Branches made up of long shoots and short shoots (= spur shoots). Leaves and fruits on spur shoots. </li></ul><ul><li>C. Fan-shaped leaves. </li></ul><ul><li>D. Dioecious . Female ovules fleshy - foul smelling. </li></ul><ul><li>E. Flagellated sperm in pollen tube. </li></ul>
    62. 63. Phylum Ginkgophyta: Ginkgo biloba Heterosporous
    63. 64. Phylum Ginkgophyta: Ginkgo biloba 1945
    64. 65. Ginkgo has free swimming sperm! Ginkgo and the cycads are the only living seed-producing plants (spermatophytes) that have motile or free swimming sperm – discovered in 1896 in a botanical garden in Tokyo
    65. 66. Chlorophyta Charophyta Liverworts Hornworts Moss Lycophyta Pterophyta Ginkgophyta Cycadophyta Coniferophyta biflagellate sperm multiflagellate sperm pollen Flagellae
    66. 67. Phylum CYCADOPHYTA - cycads <ul><li>A. Tropical and subtropical. </li></ul><ul><li>B. Palm-like with large, pinnate leaves. </li></ul><ul><li>C. Terminal cones - plants are dioecious . Strobili and seeds may take 10 years to mature. </li></ul><ul><li>D. Sperm are multiflagellated, wind-blown to female cone or some carried by beetle pollinators. Enters fluids secreted around micropyle. Pollen tube carries sperm nuclei to egg. </li></ul><ul><li>E. In lab: </li></ul><ul><ul><li>1. live Cycas </li></ul></ul><ul><ul><li>2. live Zamia - only cycad native to United States. </li></ul></ul>
    67. 68. Cycads
    68. 69. Cycads haven’t changed too much since the Paleozoic (origin) This Antarcticycas grew in Antarctica during the Triassic Period ~250 Ma
    69. 70. Phylum CONIFEROPHYTA <ul><li>500-600 species &quot;evergreens” </li></ul><ul><li>pines, firs, larches, spruce, etc. </li></ul><ul><li>Tallest = redwood 372 feet </li></ul><ul><li>Oldest = bristlecone pine >4,900 years </li></ul><ul><li>Most massive = Sequoia 102.6 feet circumference at base. </li></ul>
    70. 71. The oldest conifer fossil so far discovered is Swillingtonia denticulata , which dates from the Carboniferous of c.310 Ma. 
    71. 72. Conifers dominant
    72. 73. Sequoia Sempervirens ( Cupressaceae ) Tallest redwoods over 300 feet
    73. 74. Over 4,000 years old
    74. 75. <ul><li>A. Monoecious </li></ul><ul><li>B. Strobili = cones - borne on spur shoots </li></ul><ul><ul><li>1. Staminate cones - male - microsporangia on microsporophylls . </li></ul></ul><ul><ul><li>2. Ovulate cones - female - ovules on ovulate scales with woody bract. </li></ul></ul><ul><ul><ul><li>a. Ovule = female gametophyte (haploid) surrounded by nucellus and integument (both diploid). Mature ovule = seed. </li></ul></ul></ul><ul><li>C. Wind-blown pollen enters the ovulate cones when they are very small. Pollen tubes (immotile sperm) grow very slowly. So - fertilization may not occur for many months, even years, until the seed cones and the megagametophytes have matured. </li></ul><ul><ul><li>1. Two sperm nuclei in pollen tube but only one is functional; the other degenerates. </li></ul></ul><ul><li>D. Reproduction does not depend on water . </li></ul><ul><li>E. Well over 1 year passes between pollination and fertilization. Seeds usually not mature until 2nd summer. </li></ul><ul><li>F. Fire very important to many of these species. </li></ul>&quot;Fire Ecology&quot;
    75. 76. Pine female strobili
    76. 77. Staminate pine cones
    77. 78. The life cycle of a pine
    78. 79. Spores developing in male cones Turn to page 99 in your lab manual
    79. 80. Pine pollen
    80. 82. Kingdom Chlorophyta <ul><li>Non-vascular plants </li></ul><ul><li>Vascular Plants (no seeds) </li></ul><ul><li>Vascular seed Plants </li></ul><ul><li>Flowering Plants </li></ul>Liverworts Hornworts Mosses Lycophytes Horsetails Ferns Cycads Ginkgo Conifers Gnetum Angiosperms Green Algae
    81. 83. Chlorophyta Charophyta Liverworts Hornworts Moss Lycophytes Monilophytes Gymnosperms Angiosperms chlorophyll a and b/ Starch as a storage product/Cell wall of cellulose phragmoplast Cuticle, multicellular gametangia, embryo, multicellular sporophyte BRYOPHYTES Gametophyte dominant Gametophyte vs. sporophyte dominance
    82. 84. Principal Biological Concepts A. Charophytes as probable ancestors to terrestrial plants. B. Terrestrial adaptations. C. Alternation of generations. D. Archegonia/ antheridia. E. Vascular tissues. F. Seeds. G. Characters and synapomorphies of plant clades. Slides - Chap 7 Lab model - Marchantia Recommended Bioviewer activities
    83. 85. Cladistic Analysis exercise <ul><li>Data sheet (Relationships of Plant Taxa), pp. 103-104. </li></ul><ul><li>You must complete the taxon-character matrix. Complete everything except that for Magnolia and Gladiola this week. </li></ul><ul><li>Due at the end of class today </li></ul>