full transcript

From the Ted Talk by Lucas C. Majure: Nature's fortress How cacti keep water in and predators out

Unscramble the Blue Letters


If you were a jackrabbit hopping through the derset, you’d be glad to stumble— well, maybe not stumble— across a cactus: the succulent flesh of these patlns is a water source for many desert animals. Native to the Americas and known for their spines and succulent stems, cacti of all shapes and sizes have elovved to not just survive, but trvihe, in some of the harshest desert climates on Earth. So how do they do it?

A cactus’s spines are one key to its survival— but not for the reason you might think. Take a look at the prickly pear. Its spenis are highly modified leaves. A nramol leaf’s lgare surface area would be ill-suited to the desert, transpiring massive amounts of water under the binkag sun. The dramatically reduced sarufce area of the spines limits water loss. They also sahde the cactus and reflect the sun’s rays, rduecnig the plant's core temperature during the heat of the day. Then, at night, when air temperatures plummet, the spines act as an insulating layer, kpeenig the cactus from cooling down too much. These functions are just as important, if not more, than defending against predators.

Open Cloze


If you were a jackrabbit hopping through the ______, you’d be glad to stumble— well, maybe not stumble— across a cactus: the succulent flesh of these ______ is a water source for many desert animals. Native to the Americas and known for their spines and succulent stems, cacti of all shapes and sizes have _______ to not just survive, but ______, in some of the harshest desert climates on Earth. So how do they do it?

A cactus’s spines are one key to its survival— but not for the reason you might think. Take a look at the prickly pear. Its ______ are highly modified leaves. A ______ leaf’s _____ surface area would be ill-suited to the desert, transpiring massive amounts of water under the ______ sun. The dramatically reduced _______ area of the spines limits water loss. They also _____ the cactus and reflect the sun’s rays, ________ the plant's core temperature during the heat of the day. Then, at night, when air temperatures plummet, the spines act as an insulating layer, _______ the cactus from cooling down too much. These functions are just as important, if not more, than defending against predators.

Solution


  1. surface
  2. normal
  3. plants
  4. thrive
  5. spines
  6. baking
  7. large
  8. shade
  9. keeping
  10. desert
  11. evolved
  12. reducing

Original Text


If you were a jackrabbit hopping through the desert, you’d be glad to stumble— well, maybe not stumble— across a cactus: the succulent flesh of these plants is a water source for many desert animals. Native to the Americas and known for their spines and succulent stems, cacti of all shapes and sizes have evolved to not just survive, but thrive, in some of the harshest desert climates on Earth. So how do they do it?

A cactus’s spines are one key to its survival— but not for the reason you might think. Take a look at the prickly pear. Its spines are highly modified leaves. A normal leaf’s large surface area would be ill-suited to the desert, transpiring massive amounts of water under the baking sun. The dramatically reduced surface area of the spines limits water loss. They also shade the cactus and reflect the sun’s rays, reducing the plant's core temperature during the heat of the day. Then, at night, when air temperatures plummet, the spines act as an insulating layer, keeping the cactus from cooling down too much. These functions are just as important, if not more, than defending against predators.

Frequently Occurring Word Combinations


ngrams of length 2

collocation frequency
surface area 2
limits water 2
water loss 2
rain roots 2

ngrams of length 3

collocation frequency
limits water loss 2

Important Words


  1. act
  2. air
  3. americas
  4. amounts
  5. animals
  6. area
  7. baking
  8. cacti
  9. cactus
  10. climates
  11. cooling
  12. core
  13. day
  14. defending
  15. desert
  16. dramatically
  17. earth
  18. evolved
  19. flesh
  20. functions
  21. glad
  22. harshest
  23. heat
  24. highly
  25. hopping
  26. important
  27. insulating
  28. jackrabbit
  29. keeping
  30. key
  31. large
  32. layer
  33. leaves
  34. limits
  35. loss
  36. massive
  37. modified
  38. native
  39. night
  40. normal
  41. pear
  42. plants
  43. plummet
  44. predators
  45. prickly
  46. rays
  47. reason
  48. reduced
  49. reducing
  50. reflect
  51. shade
  52. shapes
  53. sizes
  54. source
  55. spines
  56. stems
  57. succulent
  58. sun
  59. surface
  60. survive
  61. temperature
  62. temperatures
  63. thrive
  64. transpiring
  65. water