Since the late 1980s, Harvard biologist Jonathan Losos and his colleagues have been dropping lizards onto tiny islands in the Caribbean. Sounds odd, sure, but what they’ve been doing is toying around with evolution, testing out the controversial theories behind the 70-year-old founder effect.
After Hurricane Frances swept through the Caribbean, Losos wondered what would happen if he dropped a pair of anole lizards onto each of the seven tiny islands in the Bahamas. Would they go extinct? Or, would they survive and begin building new colonies? Well, as it turned out, the couple thrived. And not only did they thrive, but they helped create 40 new lizards, according to the Washington Post.
Alright, I get it; this is how you test evolution. What’s so intriguing? Beyond the fact that Harvard biologists are dumping lizards castaway-style on remote islands, they’ve actually seen significant changes in their adaptation patterns. Within just a few generations, the back legs of the lizards began to shrink. The shorter the legs, the more agility a lizard has, and the more agile, the more insects they can catch. All of that feeds into the founder effect.
First proposed by biologist Ernst Mayr in the 1940s, the founder effect has fallen on deaf ears, primarily because Losos said you can’t observe the founder effect in nature. Defined, simply, as a loss of genetic diversity, it typically occurs when a new population is established by a very small number of individuals from a larger population (i.e. two lizards).
Losos has been one of the first ones to examine the effect, and what he’s found is that over the last five years, the average length of the lizards’ hind legs had decreased on all seven islands. Although islands that were founded by long-legged lizards at the beginning still had the longest-legged lizards at the end, fellow biologist Jason Kolbe from the University of Rhode Island told the Post “that’s the signature of the founder effect.”
Whether or not new species will develop from these lizards, biologists say it’s too early to tell. Losos does plan on revisiting in May, though. Since Hurricane Irene blew through the region last August, Losos said the team will soon see whether the lizards even survived. What he’s hoping for, however, is that there’s a greatly reduced population on each island, because that would create a second founder effect. According to researchers, “it’s repeated squeezing and winnowing of a population that drives the development of a new species.”
Could Harvard be breeding a new pool of lizards? Perhaps. Speaking as someone who went to an arts and communication college, I’m the first to admit my studies of Darwinism and evolution don’t extend beyond high school biology. Imagining these biologists dropping off lizards, in what I pretend to be parachute style, is fascinating, though.