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16 lecture presentation

  1. 1. © 2010 Pearson Education, Inc. COLONIZING LAND • Plants are terrestrial organisms that include forms that have returned to water, such as water lilies.
  2. 2. Terrestrial Adaptations of Plants Structural Adaptations • A plant is – A multicellular eukaryote – A photoautotroph, making organic molecules by photosynthesis © 2010 Pearson Education, Inc.
  3. 3. © 2010 Pearson Education, Inc. • In terrestrial habitats, the resources that a photosynthetic organism needs are found in two very different places: – Light and carbon dioxide are mainly available in the air – Water and mineral nutrients are found mainly in the soil
  4. 4. © 2010 Pearson Education, Inc. • The complex bodies of plants are specialized to take advantage of these two environments by having – Aerial leaf-bearing organs called shoots – Subterranean organs called roots
  5. 5. Reproductive structures (such as those in flowers) contain spores and gametes Leaf performs photosynthesis Cuticle reduces water loss; stomata regulate gas exchange Shoot supports plant (and may perform photosynthesis) Surrounding water supports the alga Roots anchor plant; absorb water and minerals from the soil (aided by fungi) Whole alga performs photosynthesis; absorbs water, CO2, and minerals from the water Alga Plant Figure 16.1
  6. 6. © 2010 Pearson Education, Inc. • Most plants have mycorrhizae, symbiotic fungi associated with their roots, in which the fungi – Absorb water and essential minerals from the soil – Provide these materials to the plant – Are nourished by sugars produced by the plant
  7. 7. © 2010 Pearson Education, Inc. • Leaves are the main photosynthetic organs of most plants, with – Stomata for the exchange of carbon dioxide and oxygen with the atmosphere – Vascular tissue for transporting vital materials – A waxy cuticle surface that helps the plant retain water
  8. 8. © 2010 Pearson Education, Inc. • Two types of vascular tissue exist in plants: – Xylem transports water and minerals from roots to leaves – Phloem distributes sugars from leaves to the roots
  9. 9. Phloem Xylem Oak leaf Vascular tissue Figure 16.3
  10. 10. © 2010 Pearson Education, Inc. Reproductive Adaptations • Plants produce their gametes in protective structures called gametangia, which have a jacket of protective cells surrounding a moist chamber where gametes can develop without dehydrating.
  11. 11. © 2010 Pearson Education, Inc. • The zygote develops into an embryo while still contained within the female parent in plants.
  12. 12. Embryo Maternal tissue LM Figure 16.4
  13. 13. © 2010 Pearson Education, Inc. The Origin of Plants from Green Algae • The algal ancestors of plants – Carpeted moist fringes of lakes or coastal salt marshes – First evolved over 500 million years ago
  14. 14. © 2010 Pearson Education, Inc. • Charophytes – Are a modern-day lineage of green algae – May resemble one of these early plant ancestors
  15. 15. LM LM Figure 16.5
  16. 16. © 2010 Pearson Education, Inc. PLANT DIVERSITY • The history of the plant kingdom is a story of adaptation to diverse terrestrial habitats.
  17. 17. © 2010 Pearson Education, Inc. Highlights of Plant Evolution • The fossil record chronicles four major periods of plant evolution.
  18. 18. Ancestral green algae Origin of first terrestrial adaptations (about 475 mya) Origin of vascular tissue (about 425 mya) Origin of seeds (about 360 mya) 600 500 400 300 200 100 0 Origin of flowers (about 140 mya) Millions of years ago Angiosperms Gymnosperms Ferns and other seedless vascular plants Bryophytes Charophytes (a group of green algae) Landplants Vascularplants Seedplants Seedless vascular plants Nonvascular plants (bryophytes) Figure 16.6
  19. 19. © 2010 Pearson Education, Inc. • (1) About 475 million years ago plants originated from an algal ancestor giving rise to bryophytes, nonvascular plants, including mosses, liverworts, and hornworts that are nonvascular plants without – True roots – True leaves
  20. 20. © 2010 Pearson Education, Inc. • (2) About 425 million years ago ferns evolved – With vascular tissue – But without seeds
  21. 21. © 2010 Pearson Education, Inc. • (3) About 360 million years ago gymnosperms evolved with seeds that consisted of an embryo packaged along with a store of food within a protective covering but not enclosed in any specialized chambers. • Today, conifers, consisting mainly of cone-bearing trees such as pines, are the most diverse and widespread gymnosperms.
  22. 22. PLANT DIVERSITY Bryophytes (nonvascular plants) Ferns (seedless vascular plants) Gymnosperms (naked-seed plants) Angiosperms (flowering plants) Figure 16.7
  23. 23. © 2010 Pearson Education, Inc. • (4) About 140 million years ago angiosperms evolved with complex reproductive structures called flowers that bear seeds within protective chambers called ovaries.
  24. 24. © 2010 Pearson Education, Inc. • The great majority of living plants – Are angiosperms – Include fruit and vegetable crops, grains, grasses, and most trees Video: Flower Blooming (time lapse)
  25. 25. © 2010 Pearson Education, Inc. Bryophytes • Bryophytes, most commonly mosses – Sprawl as low mats over acres of land – Need water to reproduce because their sperm swim to reach eggs within the female gametangium – Have two key terrestrial adaptations: – A waxy cuticle that helps prevent dehydration – The retention of developing embryos within the mother plant’s gametangium
  26. 26. Figure 16.8
  27. 27. © 2010 Pearson Education, Inc. • Mosses have two distinct forms: – The gametophyte, which produces gametes – The sporophyte, which produces spores
  28. 28. Spores Spore capsule Sporophyte Gametophytes Figure 16.9
  29. 29. © 2010 Pearson Education, Inc. • The life cycle of a moss exhibits an alternation of generations shifting between the gametophyte and sporophyte forms. • Mosses and other bryophytes are unique in having the gametophyte as the larger, more obvious plant. Blast Animation: Non-Flowering Plant Life Cycle Animation: Moss Life Cycle Blast Animation: Alternation of Generations
  30. 30. Gametes: sperm and eggs (n) Gametophyte (n) Key Haploid (n) Diploid (2n) osis Mit Figure 16.10-1
  31. 31. Gametes: sperm and eggs (n) Zygote (2n) Gametophyte (n) Key Haploid (n) Diploid (2n) FERTILIZATION osis Mit Figure 16.10-2
  32. 32. Spore capsule Gametes: sperm and eggs (n) Zygote (2n) Gametophyte (n) Sporophyte (2n) Key Haploid (n) Diploid (2n) FERTILIZATION osis Mit to Mi sis Figure 16.10-3
  33. 33. Spores (n) Spore capsule Gametes: sperm and eggs (n) Zygote (2n) Gametophyte (n) Sporophyte (2n) Key Haploid (n) Diploid (2n) MEIOSIS FERTILIZATION osis Mit to Mi sis Figure 16.10-4
  34. 34. Spores (n) Spore capsule Gametes: sperm and eggs (n) Zygote (2n) Gametophyte (n) Sporophyte (2n) Key Haploid (n) Diploid (2n) MEIOSIS FERTILIZATION osis M it osis Mit to Mi sis Figure 16.10-5
  35. 35. © 2010 Pearson Education, Inc. Ferns • Ferns are – Seedless vascular plants – By far the most diverse with more than 12,000 known species • The sperm of ferns, like those of mosses – Have flagella – Must swim through a film of water to fertilize eggs Animation: Fern Life Cycle
  36. 36. Spore capsule “Fiddlehead” (young leaves ready to unfurl) Figure 16.11
  37. 37. Figure 16.11a
  38. 38. Figure 16.11b
  39. 39. © 2010 Pearson Education, Inc. Gymnosperms • At the end of the Carboniferous period, the climate turned drier and colder, favoring the evolution of gymnosperms, which can – Complete their life cycles on dry land – Withstand long, harsh winters • The descendants of early gymnosperms include the conifers, or cone-bearing plants.
  40. 40. © 2010 Pearson Education, Inc. Conifers • Conifers – Cover much of northern Eurasia and North America – Are usually evergreens, which retain their leaves throughout the year – Include the tallest, largest, and oldest organisms on Earth
  41. 41. Figure 16.13
  42. 42. © 2010 Pearson Education, Inc. Terrestrial Adaptations of Seed Plants • Conifers and most other gymnosperms have three additional terrestrial adaptations: – Further reduction of the gametophyte – Pollen – Seeds
  43. 43. © 2010 Pearson Education, Inc. • Seed plants have a greater development of the diploid sporophyte compared to the haploid gametophyte generation.
  44. 44. © 2010 Pearson Education, Inc. • A pine tree or other conifer is actually a sporophyte with tiny gametophytes living in cones. Animation: Pine Life Cycle
  45. 45. © 2010 Pearson Education, Inc. • A second adaptation of seed plants to dry land was the evolution of pollen. • A pollen grain – Is actually the much-reduced male gametophyte – Houses cells that will develop into sperm
  46. 46. © 2010 Pearson Education, Inc. • The third terrestrial adaptation was the development of the seed, consisting of – A plant embryo – A food supply packaged together within a protective coat
  47. 47. © 2010 Pearson Education, Inc. • Seeds – Develop from structures called ovules, located on the scales of female cones in conifers – Can remain dormant for long periods before they germinate, as the embryo emerges through the seed coat as a seedling
  48. 48. © 2010 Pearson Education, Inc. Angiosperms • Angiosperms – Dominate the modern landscape – Are represented by about 250,000 species – Supply nearly all of our food and much of our fiber for textiles • Their success is largely due to – A more efficient water transport – The evolution of the flower
  49. 49. © 2010 Pearson Education, Inc. Flowers, Fruits, and the Angiosperm Life Cycle • Flowers help to attract pollinators who transfer pollen from the sperm-bearing organs of one flower to the egg-bearing organs of another. Video: Bat Pollinating Agave Plant Video: Bee Pollinating
  50. 50. © 2010 Pearson Education, Inc. • A flower has; – Sepals – Petals – Stamens – Carpels Blast Animation: Flower Structure
  51. 51. Petal CarpelStamen SepalOvule Anther Filament Stigma Style Ovary Figure 16.17
  52. 52. © 2010 Pearson Education, Inc. • Flowers come in many forms.
  53. 53. Pansy Bleeding heart California poppy Water lily Figure 16.18
  54. 54. Pansy Figure 16.18a
  55. 55. Bleeding heart Figure 16.18b
  56. 56. California poppy Figure 16.18c
  57. 57. Water lily Figure 16.18d
  58. 58. © 2010 Pearson Education, Inc. • Flowers are an essential element of the angiosperm life cycle. Animation: Seed Development Video: Flowering Plant Life Cycle (time lapse) Animation: Plant Fertilization Animation: Fruit Development Blast Animation: Flowering Plant Life Cycle Blast Animation: Pollination and Fertilization
  59. 59. Mature sporophyte plant with flowers Sporophyte seedling Germinating seed Seed Seed (develops from ovule) Fruit (develops from ovary) Embryo (sporophyte) Two sperm nuclei Zygote Endosperm Embryo sac (female gametophyte) Egg FERTILIZATION Key Haploid (n) Diploid (2n) Anther at tip of stamen Pollen tube growing down style of carpel Ovary (base of carpel) Ovule Germinated pollen grain (male gametophyte) on stigma of carpel Figure 16.19-6
  60. 60. © 2010 Pearson Education, Inc. • Although both have seeds – Angiosperms enclose the seed within an ovary – Gymnosperms have naked seeds
  61. 61. © 2010 Pearson Education, Inc. • Fruit – Is a ripened ovary – Helps protect the seed – Increases seed dispersal – Is a major food source for animals
  62. 62. Wind dispersal Animal transportation Animal ingestion Figure 16.20
  63. 63. Wind dispersal Figure 16.20a
  64. 64. Animal transportation Figure 16.20b
  65. 65. Animal ingestion Figure 16.20c
  66. 66. © 2010 Pearson Education, Inc. Angiosperms and Agriculture • Gymnosperms supply most of our lumber and paper. • Angiosperms – Provide nearly all our food – Supply fiber, medications, perfumes, and decoration
  67. 67. © 2010 Pearson Education, Inc. Plant Diversity as a Nonrenewable Resource • The exploding human population is – Extinguishing plant species at an unprecedented rate – Destroying fifty million acres, an area the size of the state of Washington, every year!
  68. 68. Figure 16.21
  69. 69. © 2010 Pearson Education, Inc. • Humans depend on plants for thousands of products including – Food – Building materials – Medicines
  70. 70. Table 16.1
  71. 71. © 2010 Pearson Education, Inc. • Preserving plant diversity is important to many ecosystems and humans. • Scientists are now rallying to – Slow the loss of plant diversity – Encourage management practices that use forests as resources without damaging them
  72. 72. © 2010 Pearson Education, Inc. FUNGI • Fungi – Recycle vital chemical elements back to the environment in forms other organisms can assimilate – Form mycorrhizae, fungus-root associations that help plants absorb from the soil – Minerals – Water
  73. 73. © 2010 Pearson Education, Inc. • Fungi are – Eukaryotes – Typically multicellular
  74. 74. © 2010 Pearson Education, Inc. • Fungi – Come in many shapes and sizes – Represent more than 100,000 species Video: Water Mold Zoospores Video: Water Mold Oogonium
  75. 75. Orange fungi Mold Predatory fungus Budding yeast A “fairy ring” Bud Roundworm Body of fungus ColorizedSEM ColorizedSEMColorizedSEM Figure 16.22
  76. 76. © 2010 Pearson Education, Inc. Characteristics of Fungi • Fungi have unique – Structures – Forms of nutrition
  77. 77. © 2010 Pearson Education, Inc. Fungal Nutrition • Fungi – Acquire their nutrients by absorption
  78. 78. © 2010 Pearson Education, Inc. • A fungus – Digests food outside its body – Secretes powerful digestive enzymes to break down the food – Absorbs the simpler food compounds
  79. 79. © 2010 Pearson Education, Inc. Fungal Structure • The bodies of most fungi are constructed of threadlike filaments called hyphae. • Hyphae are minute threads of cytoplasm surrounded by a – Plasma membrane
  80. 80. © 2010 Pearson Education, Inc. • Hyphae branch repeatedly, forming an interwoven network called a mycelium (plural, mycelia), the feeding structure of the fungus. Animation: Fungal Reproduction and Nutrition
  81. 81. Reproductive structure Mycelium Mycelium Hyphae Spore-producing structures Figure 16.23
  82. 82. Mycelium Spore-producing structures Reproductive structure Hyphae Figure 16.23a
  83. 83. © 2010 Pearson Education, Inc. The Ecological Impact of Fungi • Fungi have – An enormous ecological impact – Many interactions with humans
  84. 84. © 2010 Pearson Education, Inc. Fungi as Decomposers • Fungi and bacteria – Are the principal decomposers of ecosystems – Keep ecosystems stocked with the inorganic nutrients necessary for plant growth • Without decomposers, carbon, nitrogen, and other elements would accumulate in nonliving organic matter.
  85. 85. © 2010 Pearson Education, Inc. Parasitic Fungi • Parasitic fungi absorb nutrients from the cells or body fluids of living hosts. • Of the 100,000 known species of fungi, about 30% make their living as parasites, including – Dutch elm disease – Deadly ergot, which infests grain
  86. 86. (a) American elm trees killed by Dutch elm disease fungus Figure 16.24a
  87. 87. (b) Ergots Figure 16.24b
  88. 88. © 2010 Pearson Education, Inc. • About 50 species of fungi are known to be parasitic in humans and other animals, causing – Lung and vaginal yeast infections – Athlete’s foot
  89. 89. © 2010 Pearson Education, Inc. Commercial Uses of Fungi • Fungi are commercially important. Humans eat them and use them to – Produce medicines such as penicillin – Decompose wastes – Produce bread, beer, wine, and cheeses
  90. 90. Truffles (the fungal kind, not the chocolates) Blue cheese Chanterelle mushrooms Figure 16.26
  91. 91. Truffles (the fungal kind, not the chocolates) Figure 16.26a
  92. 92. Blue cheese Figure 16.26b
  93. 93. Chanterelle mushrooms Figure 16.26c
  94. 94. Penicillium Zone of inhibited growth Staphylococcus Figure 16.27

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