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← How did plants change our planet? | California Academy of Sciences

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Showing Revision 1 created 10/02/2019 by thuuyen.

  1. music
  2. today my job is easy
  3. i get to tell you about my favorite thing
    in the world, plants
  4. the very first plant plants to be exact
  5. it is a lovely story about how overtime,
  6. tiny plants can rise to
    more complex plants
  7. that is basically changed the world
  8. let's go back millions
  9. and millions

  10. of years
  11. we're not going to see the dinosaurs, sorry
  12. we are going to go back further in time
    to the time of the very first plant plants
  13. I wouldn't wanna live here
    but who would?
  14. these plants woulds
  15. the first plants on land was tiny
  16. they did not have roots or vascular system
  17. plant has roots to take up water from soil
  18. because these early plants did not
    have roots
  19. they had to live close to water
  20. like rivers and ponds
  21. a vascular system is how water and
    nutrients are moved around the plants
  22. but that would be pluming plants can
    grow in large
  23. because some part would get water
  24. the first plans were similar to
    that we see today
  25. they also don't have real roots
  26. so after few million years, plans develop
    roots and pluming
  27. the roots allow them to tap into water
    into ground
  28. helping them move away from whatever areas
  29. with pots carry water of its stems
  30. plants can grow as taller and taller
  31. as they can start to compete with
    each other for sunlight
  32. and here is when the story get
    really interesting
  33. as plants develop roots
  34. they physically and chemically change
    the surface in our planet
  35. first, they create soil
  36. roots penetrate rocky and at the
    same time of the surface
  37. and as they grow deeper and deeper
  38. they break the rock up into smaller
    and smaller pieces
  39. the roots also use carbon dioxide to
    produce acid
  40. to break down the rock in further
  41. finally, as plants dive into cave
  42. they add nutrients making the soil much richer
  43. but that's not all these early plant
    plans are doing
  44. they are also affecting the climate
  45. plants take in carbon dioxide from
    the atmosphere
  46. throw far
    plants use light from the sun
  47. to convert that carbon dioxide plus water
    into sugar and oxygen
  48. they release the oxygen back
    into the atmosphere
  49. but they use the energy from the sugar
    to grow
  50. a lot of the sugar becomes
    the warm material
  51. that makes up the structure of the plants
  52. a centrally locking up the carbon from
    the carbon dioxide
  53. it originally absorb in its tissue
  54. when the plans die, they on the
    ground
  55. and some of that plan material
    including its carbon
  56. get trapped in the soil
  57. but why this more
  58. remember how the plans use carbon dioxide
    to produce acide
  59. to react with rocky soil
    even more carbon dioxide
  60. the carbon dioxide in the atmosphere
    our planet are warm
  61. so with lesser in the air
  62. The planet slowly cool down
    during its period
  63. see how plants drastically transform
    our planet forever
  64. we actually have evidence for
    most of this story
  65. we do have fossil of them
  66. how do we know these plants
  67. well, because the look a lot like the
    plants we still have nowadays
  68. here we have a living liver wood
  69. and here is the magnificent of
    of the fossil one
  70. so this show is the plants were really
    small
  71. without and without roots
  72. so when plants develop roots and
    pluming
  73. they could grow in different places
    and they also get more
  74. so that means the record
    get better and better
  75. uh hum,
    what are we looking at here,Cindy?
  76. well, here I have a fossil of the
    plants I was still relatively small
  77. here are their stems
  78. and you can see that it wasn't
    getting very big
  79. now compare that with this younger one
  80. this is a stem as well
  81. it's cross section
    have its trunk actually
  82. so this was a tree
  83. and we also have the branches
    that's grand it, over here
  84. we have fossil like soil, too
  85. and they can save soil from
    volcanic today
  86. we can use that information to understand
  87. how early plant plan creat soil
  88. at the same time, as plants are getting
    bigger and bigger
  89. the temperature of the planet
    start to drop
  90. and this is where the evidence
    for this lies
  91. and the shells of
    the ancient marine organism
  92. what's amazing is that scientist
    can actually measure
  93. the temperature the environment
    where these shells warm
  94. and we can do the same
    with fossil soil too
  95. see how plants drastically transform
    our planet forever
  96. thanks plants
  97. music