BBC Learnings · Section 2

Climate change and evolution

Now, when we think about famous figures in the history of science, the name of Charles Darwin often comes up.

Level: B2 · 79 sentences

Transcript

  1. Now, when we think about famous figures in the history of science,
  2. the name of Charles Darwin often comes up.
  3. Darwin is most famous for his theory of evolution
  4. the idea that animals change and adapt in response to their environment.
  5. In the 1830s he visited the Galapagos,
  6. a string of islands in the Pacific Ocean famous because of the unique animals living there.
  7. It was while in the Galapagos observing small birds called finches that Darwin started forming his theory of evolution.
  8. But today the animals of the Galapagos
  9. face the same pressures as animals across the world
  10. because of the effects of man-made climate change.
  11. Warming sea waters and more frequent extreme weather events are affecting animals as much as humans,
  12. so in this programme we'll be asking,
  13. can animals evolve to deal with climate change?
  14. But first, I have a question for you, Sam,
  15. and it's about Charles Darwin's trip to the Galapagos.
  16. In 1831, Darwin set sail around the world collecting samples of flora
  17. and fauna the plants and animals of the places he visited.
  18. But what was the name of the ship he sailed in?
  19. Was it A, HMS Beagle, B, HMS Victory, or C, SS Great Britain?
  20. Maybe it was B, HMS Victory?
  21. Are you sure?
  22. No. OK. Well, I'll reveal the correct answer later in the programme.
  23. Now, it may have been the Galapagos finches that started Charles Darwin thinking about how animals adapt to their environment,
  24. but as naturalist Kyoko Gotanda explained to BBC World Service programme The Climate Question,
  25. Darwin's first impression of the small birds wasn't very good.
  26. When Darwin got to the Galapagos Islands,
  27. he actually wasn't that interested in the finches.
  28. They were kind of a drab colour and they didn't have a very interesting song.
  29. He sampled, though, the finches from different islands.
  30. And so when he got back to England
  31. and he was looking at all the variation in beak shape and size
  32. and body size and shape,
  33. and he was recalling how certain finches were found on certain islands but not on other islands.
  34. In contrast to more colourful birds like Galapagos parrots, The finches,
  35. Darwin observed, were drab, dull and boring-looking, with little colour.
  36. Instead, what Darwin noticed were variations in the finch's beak,
  37. the hard, pointed part of a bird's mouth.
  38. Finches born with a beak that could help them get more food were more likely to survive and have babies.
  39. Over time, as the birds passed on their successful genes,
  40. they adapted to fit in with their environment.
  41. what we know as evolution.
  42. So if animals can evolve to survive their environment,
  43. can they also evolve to cope with the impact humans are having on the climate?
  44. Well, there's already some evidence to show they can.
  45. Studies on birds in the Brazilian Amazon
  46. and red deer on the Isle of Rum in Scotland
  47. show warmer temperatures have caused animals to evolve smaller bodies.
  48. It's easier to keep cool when you're small.
  49. American conservationist Thor Hansen records and measures anoli lizards in the Caribbean.
  50. He wants to see how the effects of man-made climate change – in this case hurricanes – is affecting the lizards.
  51. Listen to what Thor found out as he speaks with presenters of BBC World Service's The Climate Question.
  52. But what you can see is that large toe pads and strong front legs give some lizards a tighter grip.
  53. When they do start to let go and their body starts flapping in the air like a flag,
  54. smaller back legs reduce the drag and allow them to cling on and survive the hurricane.
  55. So the survivors were those lizards with those characteristics and they passed those traits along to their offspring.
  56. Thor's lizards develop stronger front legs and smaller back legs,
  57. allowing them to cling on,
  58. hold on to something tightly when hurricanes pass through.
  59. It's this trait, a genetically determined characteristic,
  60. that allows the lizards to survive and is passed on to their babies.
  61. Thor checked other areas of the Caribbean where hurricanes were frequent and found the same traits in lizards there.
  62. Proof of evolution in action.
  63. But whereas we often think of evolution happening over hundreds,
  64. even thousands of years,
  65. the changes in the Caribbean lizards happened in around 40 years.
  66. something that would have surprised Charles Darwin.
  67. Rich reminds me of your question, Rob.
  68. Ah yes, I asked you the name of the ship Darwin sailed around the world in.
  69. Darwin's ship was called the HMS Beagle and,
  70. appropriately enough, it was named after an animal.
  71. A beagle is a type of dog.
  72. OK, let's recap the vocabulary from this programme about evolution
  73. the way living things adapt to their environment
  74. and pass these adaptations onto their children.
  75. Flora and fauna is another way of saying the plants and animals of a place.
  76. Drab means dull and colourless in appearance.
  77. A bird's beak is the hard, pointed part of its mouth.
  78. To cling on means to hold on very tightly.
  79. And finally, a trait is a genetically determined characteristic.