full transcript

From the Ted Talk by Joao Pedro de Magalhaes: Why do animals have such different lifespans?

Unscramble the Blue Letters

For the microscopic lab worm, C. elegans life equates to just a few short wekes on Earth. Compare that with the tortoise, which can age to more than 100 years. Mice and rats recah the end of their lives after just four years, while for the bawoehd whale, Earth's longest-lived mammal, death can come after 200. Like most living things, the vast majority of animals gradually degenerate after ranceihg sexual maturity in the process known as aging. But what does it really mean to age? The drivers behind this process are varied and complicated, but aging is ultimately caused by cell death and dysfunction. When we're young, we caltnnsoty regenerate cells in order to replace dead and dying ones. But as we age, this process slows down. In addition, older cells don't perform their functions as well as young ones. That makes our bodies go into a decline, which eventually results in dsaseie and death. But if that's consistently true, why the huge vianarce in aging patterns and lifespan within the animal kingdom? The answer lies in several factors, including environment and body size. These can place powerful evolutionary pressures on animals to adpat, which in turn makes the agnig process different across species. Consider the cold depths of the Atlantic and Arctic Seas, where Greenland sharks can live to over 400 years, and the Arctic clam known as the quhoag can live up to 500. Perhaps the most impressive of these ocean-dwelling aencints is the Antarctic glsas sopnge, which can survive over 10,000 years in frigid watres. In cold eirmvenntons like these, heartbeats and mtaioelbc rates slow down. Researchers trezihoe that this also causes a sniolwg of the aging process. In this way, the enrmennvoit spehas lneoivgty. When it comes to size, it's often, but not always, the case that larger species have a longer lifespan than smaller ones. For instance, an elephant or whale will live much longer than a mouse, rat, or vole, which in turn have yraes on flies and wroms. Some small amanlis, like worms and flies, are also limited by the mechanics of their cell division. They're mostly made up of clels that can't divide and be replaced when damaged, so their bodies expire more qcukliy. And size is a powerful evolutionary driver in animals. Smaller creatures are more prone to peoartrds. A mouse, for instance, can hardly eecxpt to survive more than a year in the wild. So, it has evolved to grow and reproduce more rapidly, like an evolutionary defense mshncieam against its shorter lifespan. lreagr animals, by contrast, are better at fending off predators, and so they have the luxury of time to grow to large sizes and reproduce multiple times during their lives. Exceptions to the size rule include bats, birds, moels, and turtles, but in each case, these animals have other adaptations that allow them to escape predators. But there are still cases where animals with similar defining ferutaes, like size and habitat, age at completely different rteas. In these cases, genetic differences, like how each organism's cells respond to threats, often ancocut for the discrepancies in longevity. So it's the combination of all these factors playing out to differing deeergs in different animals that explains the virablatiiy we see in the animal kingdom. So what about us? haumns currently have an average life etaxcnpcey of 71 years, meaning that we're not even close to being the longest living inhabitants on Earth. But we are very good at increasing our life expectancy. In the early 1900s, humans only lived an average of 50 years. Since then, we've learned to adapt by managing many of the factors that cause deaths, like environmental erspxuoe and nutrition. This, and other increases in life expectancy make us psiolsby the only species on Earth to take control over our natural fate.

Open Cloze

For the microscopic lab worm, C. elegans life equates to just a few short _____ on Earth. Compare that with the tortoise, which can age to more than 100 years. Mice and rats _____ the end of their lives after just four years, while for the _______ whale, Earth's longest-lived mammal, death can come after 200. Like most living things, the vast majority of animals gradually degenerate after ________ sexual maturity in the process known as aging. But what does it really mean to age? The drivers behind this process are varied and complicated, but aging is ultimately caused by cell death and dysfunction. When we're young, we __________ regenerate cells in order to replace dead and dying ones. But as we age, this process slows down. In addition, older cells don't perform their functions as well as young ones. That makes our bodies go into a decline, which eventually results in _______ and death. But if that's consistently true, why the huge ________ in aging patterns and lifespan within the animal kingdom? The answer lies in several factors, including environment and body size. These can place powerful evolutionary pressures on animals to _____, which in turn makes the _____ process different across species. Consider the cold depths of the Atlantic and Arctic Seas, where Greenland sharks can live to over 400 years, and the Arctic clam known as the ______ can live up to 500. Perhaps the most impressive of these ocean-dwelling ________ is the Antarctic _____ ______, which can survive over 10,000 years in frigid ______. In cold ____________ like these, heartbeats and _________ rates slow down. Researchers ________ that this also causes a _______ of the aging process. In this way, the ___________ ______ _________. When it comes to size, it's often, but not always, the case that larger species have a longer lifespan than smaller ones. For instance, an elephant or whale will live much longer than a mouse, rat, or vole, which in turn have _____ on flies and _____. Some small _______, like worms and flies, are also limited by the mechanics of their cell division. They're mostly made up of _____ that can't divide and be replaced when damaged, so their bodies expire more _______. And size is a powerful evolutionary driver in animals. Smaller creatures are more prone to _________. A mouse, for instance, can hardly ______ to survive more than a year in the wild. So, it has evolved to grow and reproduce more rapidly, like an evolutionary defense _________ against its shorter lifespan. ______ animals, by contrast, are better at fending off predators, and so they have the luxury of time to grow to large sizes and reproduce multiple times during their lives. Exceptions to the size rule include bats, birds, _____, and turtles, but in each case, these animals have other adaptations that allow them to escape predators. But there are still cases where animals with similar defining ________, like size and habitat, age at completely different _____. In these cases, genetic differences, like how each organism's cells respond to threats, often _______ for the discrepancies in longevity. So it's the combination of all these factors playing out to differing _______ in different animals that explains the ___________ we see in the animal kingdom. So what about us? ______ currently have an average life __________ of 71 years, meaning that we're not even close to being the longest living inhabitants on Earth. But we are very good at increasing our life expectancy. In the early 1900s, humans only lived an average of 50 years. Since then, we've learned to adapt by managing many of the factors that cause deaths, like environmental ________ and nutrition. This, and other increases in life expectancy make us ________ the only species on Earth to take control over our natural fate.

Solution

  1. features
  2. years
  3. expect
  4. mechanism
  5. possibly
  6. account
  7. animals
  8. sponge
  9. environment
  10. expectancy
  11. theorize
  12. weeks
  13. humans
  14. quahog
  15. rates
  16. larger
  17. slowing
  18. degrees
  19. variance
  20. adapt
  21. reach
  22. reaching
  23. exposure
  24. ancients
  25. bowhead
  26. aging
  27. glass
  28. longevity
  29. moles
  30. waters
  31. constantly
  32. metabolic
  33. shapes
  34. predators
  35. quickly
  36. cells
  37. variability
  38. disease
  39. environments
  40. worms

Original Text

For the microscopic lab worm, C. elegans life equates to just a few short weeks on Earth. Compare that with the tortoise, which can age to more than 100 years. Mice and rats reach the end of their lives after just four years, while for the bowhead whale, Earth's longest-lived mammal, death can come after 200. Like most living things, the vast majority of animals gradually degenerate after reaching sexual maturity in the process known as aging. But what does it really mean to age? The drivers behind this process are varied and complicated, but aging is ultimately caused by cell death and dysfunction. When we're young, we constantly regenerate cells in order to replace dead and dying ones. But as we age, this process slows down. In addition, older cells don't perform their functions as well as young ones. That makes our bodies go into a decline, which eventually results in disease and death. But if that's consistently true, why the huge variance in aging patterns and lifespan within the animal kingdom? The answer lies in several factors, including environment and body size. These can place powerful evolutionary pressures on animals to adapt, which in turn makes the aging process different across species. Consider the cold depths of the Atlantic and Arctic Seas, where Greenland sharks can live to over 400 years, and the Arctic clam known as the quahog can live up to 500. Perhaps the most impressive of these ocean-dwelling ancients is the Antarctic glass sponge, which can survive over 10,000 years in frigid waters. In cold environments like these, heartbeats and metabolic rates slow down. Researchers theorize that this also causes a slowing of the aging process. In this way, the environment shapes longevity. When it comes to size, it's often, but not always, the case that larger species have a longer lifespan than smaller ones. For instance, an elephant or whale will live much longer than a mouse, rat, or vole, which in turn have years on flies and worms. Some small animals, like worms and flies, are also limited by the mechanics of their cell division. They're mostly made up of cells that can't divide and be replaced when damaged, so their bodies expire more quickly. And size is a powerful evolutionary driver in animals. Smaller creatures are more prone to predators. A mouse, for instance, can hardly expect to survive more than a year in the wild. So, it has evolved to grow and reproduce more rapidly, like an evolutionary defense mechanism against its shorter lifespan. Larger animals, by contrast, are better at fending off predators, and so they have the luxury of time to grow to large sizes and reproduce multiple times during their lives. Exceptions to the size rule include bats, birds, moles, and turtles, but in each case, these animals have other adaptations that allow them to escape predators. But there are still cases where animals with similar defining features, like size and habitat, age at completely different rates. In these cases, genetic differences, like how each organism's cells respond to threats, often account for the discrepancies in longevity. So it's the combination of all these factors playing out to differing degrees in different animals that explains the variability we see in the animal kingdom. So what about us? Humans currently have an average life expectancy of 71 years, meaning that we're not even close to being the longest living inhabitants on Earth. But we are very good at increasing our life expectancy. In the early 1900s, humans only lived an average of 50 years. Since then, we've learned to adapt by managing many of the factors that cause deaths, like environmental exposure and nutrition. This, and other increases in life expectancy make us possibly the only species on Earth to take control over our natural fate.

Frequently Occurring Word Combinations

ngrams of length 2

collocation frequency
life expectancy 3
powerful evolutionary 2
aging process 2

Important Words

  1. account
  2. adapt
  3. adaptations
  4. addition
  5. age
  6. aging
  7. ancients
  8. animal
  9. animals
  10. answer
  11. antarctic
  12. arctic
  13. atlantic
  14. average
  15. bats
  16. birds
  17. bodies
  18. body
  19. bowhead
  20. case
  21. cases
  22. caused
  23. cell
  24. cells
  25. clam
  26. close
  27. cold
  28. combination
  29. compare
  30. completely
  31. complicated
  32. consistently
  33. constantly
  34. contrast
  35. control
  36. creatures
  37. damaged
  38. dead
  39. death
  40. deaths
  41. decline
  42. defense
  43. defining
  44. degenerate
  45. degrees
  46. depths
  47. differences
  48. differing
  49. discrepancies
  50. disease
  51. divide
  52. division
  53. driver
  54. drivers
  55. dying
  56. dysfunction
  57. early
  58. earth
  59. elegans
  60. elephant
  61. environment
  62. environmental
  63. environments
  64. equates
  65. escape
  66. eventually
  67. evolutionary
  68. evolved
  69. exceptions
  70. expect
  71. expectancy
  72. expire
  73. explains
  74. exposure
  75. factors
  76. fate
  77. features
  78. fending
  79. flies
  80. frigid
  81. functions
  82. genetic
  83. glass
  84. good
  85. gradually
  86. greenland
  87. grow
  88. habitat
  89. heartbeats
  90. huge
  91. humans
  92. impressive
  93. include
  94. including
  95. increases
  96. increasing
  97. inhabitants
  98. instance
  99. kingdom
  100. lab
  101. large
  102. larger
  103. learned
  104. lies
  105. life
  106. lifespan
  107. limited
  108. live
  109. lived
  110. lives
  111. living
  112. longer
  113. longest
  114. longevity
  115. luxury
  116. majority
  117. mammal
  118. managing
  119. maturity
  120. meaning
  121. mechanics
  122. mechanism
  123. metabolic
  124. mice
  125. microscopic
  126. moles
  127. mouse
  128. multiple
  129. natural
  130. nutrition
  131. older
  132. order
  133. patterns
  134. perform
  135. place
  136. playing
  137. possibly
  138. powerful
  139. predators
  140. pressures
  141. process
  142. prone
  143. quahog
  144. quickly
  145. rapidly
  146. rat
  147. rates
  148. rats
  149. reach
  150. reaching
  151. regenerate
  152. replace
  153. replaced
  154. reproduce
  155. researchers
  156. respond
  157. results
  158. rule
  159. seas
  160. sexual
  161. shapes
  162. sharks
  163. short
  164. shorter
  165. similar
  166. size
  167. sizes
  168. slow
  169. slowing
  170. slows
  171. small
  172. smaller
  173. species
  174. sponge
  175. survive
  176. theorize
  177. threats
  178. time
  179. times
  180. tortoise
  181. true
  182. turn
  183. turtles
  184. ultimately
  185. variability
  186. variance
  187. varied
  188. vast
  189. vole
  190. waters
  191. weeks
  192. whale
  193. wild
  194. worm
  195. worms
  196. year
  197. years
  198. young