Six-week evolution
“WE’RE beginning to see evidence of evolutionary processes playing out in real time,” says Hanson, with “genetic change occurring rapidly”. Just look at the anole lizard on the Turk and Caicos islands in the Caribbean.
Scientists surveyed the lizards ahead of a recent hurricane season, measuring the creatures and charting their body types. Not long after the study, says Hanson, “two category five hurricanes flattened the islands”. The same team of scientists returned six weeks later to see what effect the wild weather had on the lizards. The results were astounding, showing that evolution can now take place in just a matter of weeks thanks to humans tampering with nature … those hurricanes were made more deadly by climate change caused by us, after all.
Of the lizards which survived, all had larger toes, bigger front legs and shorter back legs than the average pre-hurricane population. Put simply, lizards which had similar characteristics could hang on better to trees and survive storms while those with shorter toes and front legs and longer back legs just blew away and died. All lizards on the islands now have these new characteristics. “The scientists saw survival of the fittest in action. They saw a step in the evolution of these lizards driven by climate change play out in six weeks. It’s truly amazing,” Hanson says.
Scientists then investigated the lizard populations of other Caribbean islands and found that wherever extreme storms hit, lizards had evolved these new physical characteristics. The “long-term evolution” of the lizards has now been changed forever by the actions of humanity.
Other creatures aren’t so adept at adaption – like the killer whales off the north-west coast of America. “Their populations have become specialists,” Hanson says. The orcas are experts at catching one fish: chinook salmon, the choicest, fattest fish in the sea. The orcas “are now in a world of hurt because the salmon are dwindling from habitat loss and climate change, so those whales are absolutely struggling at the moment”.