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

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 lgrae surface area would be ill-suited to the desert, trrnipisnag massive amounts of water under the baking sun. The dramatically rdueced surface area of the spines limits water loss. They also shade the ccutas and reflect the sun’s rays, reducing the plant's core tuerramptee during the heat of the day. Then, at night, when air temperatures plummet, the snepis act as an inliunastg layer, keeping the cactus from cooling down too much. These functions are just as iaropnmtt, if not more, than defending against predators.

Open Cloze

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 _____ surface area would be ill-suited to the desert, ___________ massive amounts of water under the baking sun. The dramatically _______ surface area of the spines limits water loss. They also shade the ______ and reflect the sun’s rays, reducing the plant's core ___________ during the heat of the day. Then, at night, when air temperatures plummet, the ______ act as an __________ layer, keeping the cactus from cooling down too much. These functions are just as _________, if not more, than defending against predators.

Solution

  1. important
  2. insulating
  3. transpiring
  4. temperature
  5. reduced
  6. large
  7. cactus
  8. spines

Original Text

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. amounts
  4. area
  5. baking
  6. cactus
  7. cooling
  8. core
  9. day
  10. defending
  11. desert
  12. dramatically
  13. functions
  14. heat
  15. highly
  16. important
  17. insulating
  18. keeping
  19. key
  20. large
  21. layer
  22. leaves
  23. limits
  24. loss
  25. massive
  26. modified
  27. night
  28. normal
  29. pear
  30. plummet
  31. predators
  32. prickly
  33. rays
  34. reason
  35. reduced
  36. reducing
  37. reflect
  38. shade
  39. spines
  40. sun
  41. surface
  42. temperature
  43. temperatures
  44. transpiring
  45. water