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Biology - Chp 22 - Plant Diversity - PowerPoint

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Biology - Chp 22 - Plant Diversity - PowerPoint

  1. 1. Chapter 22 Plant Diversity
  2. 2. 22–1 Introduction to Plants
  3. 3. Objectives• Explain what a plant is• Describe what plants need to survive• Describe how plants first evolved
  4. 4. What Is a Plant?• Plants are members of the kingdom Plantae• Plants are multicellular eukaryotes that have cell walls made of cellulose. They develop from multicellular embryos and carry out photosynthesis using the green pigments chlorophyll a and b
  5. 5. The Plant Life Cycle• Plants have life cycles that are characterized by alternation of generations• the two generations are the haploid (N) gametophyte, or gamete-producing plant, and the diploid (2N) sporophyte, or spore- producing plant.
  6. 6. What Plants Need to Survive1. Sunlight2. Water and Minerals3. Gas Exchange4. Movement of water and nutrients
  7. 7. Early Plants• The first plants evolved from an organism much like the multicellular green algae living today.
  8. 8. The First Plants• The first true plants were still dependent on water to complete their life cycles, similar to today’s mosses in that they were simple in structure and grew close to the ground.
  9. 9. • From these plant pioneers,several major groups of plantsevolved.
  10. 10. Mosses
  11. 11. Ferns
  12. 12. Cone Bearing Plant
  13. 13. Flowering plant
  14. 14. Overview of the Plant Kingdom• Botanists divide the plant kingdom into four groups based on three important features:1. Water conducting tissues2. Seeds3. Flowers
  15. 15. 22 – 2 Bryophytes a.k.a (Non-vascular plants)
  16. 16. Objectives• Describe the adaptations of Bryophytes
  17. 17. bryophytes• Type of early plant with no vascular tissue that draw water in their cells by osmosis.
  18. 18. Moss
  19. 19. Liverwort
  20. 20. Hornwort
  21. 21. • During at least one stage of their life cycle, bryophytes produce sperm that must swim through water to reach eggs of other individuals.• Therefore, they must live in places where there is rainfall or dew for at least part of the year
  22. 22. AsexualReproductivePartSexualReproductive/Photosynthetic Part
  23. 23. 22–3 SeedlessVascular Plants
  24. 24. Objectives• Explain how vascular tissue is important to ferns and their relatives• Describe the three phyla of spore- bearing plants• Identify the stages in the cycle of ferns
  25. 25. • In just a few million years, plants grew to a whole new scale on the landscape.Q: What caused this increase in size?A: Vascular Tissue
  26. 26. Vascular tissue• A type of tissue that is specialized to conduct water and nutrients through the body of the plant
  27. 27. Evolution of Vascular Tissue• Both forms of vascular tissue— xylem and phloem—can move fluids throughout the plant body, even against the force of gravity.
  28. 28. Xylem• Carry water upwards from the roots to every part of the plant
  29. 29. Phloem• Transports nutrients and carbohydrates produced by photosynthesis from the leaves down to the roots
  30. 30. • Vascular plants also evolved the ability to produce lignin, a substance that makes cell walls rigid.• The presence of lignin allows vascular plants to grow upright and tall
  31. 31. Ferns and Their Relatives• Seedless vascular plants include club mosses, horsetails, and ferns.• Like other vascular plants, ferns and their relatives have true roots, leaves, and stems.
  32. 32. Roots• Absorb water and minerals
  33. 33. Leaves• Collect light for photosynthesis
  34. 34. Veins• Made of xylem and phloem
  35. 35. Stems• Used for support, connect roots and leaves, carry water between them
  36. 36. Club Mosses
  37. 37. Horsetails
  38. 38. Ferns Underground Stem
  39. 39. 22 – 4 Seed Plants
  40. 40. Objectives• Describe the reproductive adaptations of seed plants• Describe the evolution of seed plants• Identify the four groups of gymnosperms
  41. 41. • Over millions of years, plants with a single trait—the ability to form seeds—became the most dominant group of photosynthetic organisms on land.• Seed plants are divided into two groups:
  42. 42. Gymnosperms• Cone plants• Bear their seeds directly on the surfaces of conesEx.) conifers, pines, spruces, cycads, ancient ginkgoes and gnetophytes
  43. 43. Angiosperms• Flowering plants• Bear their seeds within a layer of tissue that protects the seedEx.) grasses, flowering trees shrubs, wild flowers
  44. 44. Reproduction Free From Water• Unlike mosses and ferns, however, seed plants do not require water for fertilization of gametes.Q: Why was this an advantage?A: They could live further away from water• Adaptations that allow seed plants to reproduce without water include flowers or cones, the transfer of sperm by pollination, and the protection of embryos in seeds.
  45. 45. Cones and Flowers
  46. 46. Cones• Seed bearing structures of gymnosperms
  47. 47. Flowers• Seed bearing structures of angiosperms
  48. 48. Pollen
  49. 49. Pollen grain• Contains the male gamete
  50. 50. Pollination• The transfer of pollen from the male gametophyte to the female gametophyte
  51. 51. Seeds
  52. 52. seed• An embryo of a plant that is encased in a protective covering and surrounded by a food supply
  53. 53. embryo• Early development stage of a sporophyte plant• The seed’s food supply provides nutrients to the embryo as it grows
  54. 54. Seed Coat• Surrounds and protects the embryo and keeps the contents of the seed from drying out• Can be specialized for dispersal
  55. 55. Evolution of Seed Plants• Over a period of millions of years, continents became much drier, making it harder for seedless plants to survive and reproduce.• For that reason, many moss and fern species became extinct. They were replaced by seed plants with adaptations that equipped them to deal with drier conditions.
  56. 56. Gymnosperms—Cone Bearers• The most ancient surviving seed plants are the gymnosperms.• Gymnosperms include:
  57. 57. Gnetophytes
  58. 58. Cycads
  59. 59. Ginkos
  60. 60. Conifers
  61. 61. 22–5 Angiosperms - Flowering Plants
  62. 62. Objectives• Identify the characteristics of angiosperms• Explain what monocots and dicots are• Describe the three different life spans of angiosperms
  63. 63. • Flowering plants originated on land and quickly came to dominate Earth’s plant life.• The vast majority of living plant species reproduce with flowers.
  64. 64. Flowers and Fruits• Angiosperms have unique reproductive organs known as flowers.Q: Why are flowers evolutionary adaptations?A: they attract animals that pollinate them
  65. 65. • Flowers contain ovaries, which surround and protect the seeds• After pollination, the ovary develops into a fruit, which protects the seed and aids in its dispersal.
  66. 66. Fruit• Ripened ovary, thick wall of tissue that surrounds the seed
  67. 67. Diversity of Angiosperms• The angiosperms are an incredibly diverse group. Not surprisingly, there are many different ways of categorizing these plants.
  68. 68. Monocots and Dicots• Monocots and dicots are named for the number of seed leaves, or cotyledons, in the plant embryo. Monocots have one seed leaf, and dicots have two seed leafs
  69. 69. Woody and Herbaceous Plants• Woody plants – Have woody stemsEx.) trees, shrubs, vines
  70. 70. Herbaceous Plants• Plant stems that are smooth and nonwoodyEx.) dandelions, petunias, and sunflowers
  71. 71. Annuals, Biennials, and Perennials
  72. 72. Annuals• Angiosperms that complete a life cycle within one growing season
  73. 73. Biennials• Angiosperms that complete their life cycle in two years• In the first year, biennials germinate and grow roots, stems, leaves• During their second year, biennials grow new stems and leaves and then produce flowers and seeds
  74. 74. Perennials• Flowering plants that live for more than two years

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