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5 December 2013 11:26 am ,
Vol. 342 ,
Dyslexia, a learning disability that hinders reading, hasn't been associated with deficits in vision, hearing, or...
Exotic, elusive, and dangerous, snakes have fascinated humankind for millennia. They can be hard to find, yet their...
Researchers have sequenced and analyzed the first two snake genomes, which represent two evolutionary extremes. The...
Snake venoms are remarkably complex mixtures that can stun or kill prey within minutes. But more and more researchers...
At age 30, Dutch biologist Freek Vonk has built up a respectable career as a snake scientist. But in his home country,...
Since arriving on the island of Guam in the 1940s, the brown tree snake ( Boiga irregularis ) has extirpated native...
An animal rights group known as the Nonhuman Rights Project filed lawsuits in three New York courts this week in an...
Researchers have been hot on the trail of the elusive Denisovans, a type of ancient human known only by their DNA and...
- 5 December 2013 11:26 am , Vol. 342 , #6163
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Lizards Take Convergent Evolution to Extreme
27 March 1998 6:00 pm
If evolution started all over again, would it repeat itself? In today's issue of Science, a real-life version of this thought experiment suggests that the answer may be yes--at least for island lizards.
Evolutionary ecologist Jonathan Losos of Washington University in St. Louis and his colleagues report that anole lizards on the four islands of the Greater Antilles--Hispaniola, Cuba, Jamaica, and Puerto Rico--independently evolved the same set of habitat-specialized traits. Although examples of convergent evolution, such as wings on bats and birds, are well known, "what's remarkable here is the degree of similarity that has evolved on all four of the islands," says Douglas Futuyma of the State University of New York, Stony Brook.
Losos and his team measured six characteristics that are linked to habitat, including mass, size of toepads, and length of body, tail, and legs, in about a dozen lizards from each of 46 species. They found that each species was, on average, most like those living in the same habitat on other islands--even if the species were only distantly related. The researchers conclude that the original lizard immigrants--likely a different species for each island--were subjected to similar evolutionary pressures and independently evolved into similar forms. "In this case, the power of natural selection is so strong that it overwhelms any differences between the islands and what has gone on there before," Losos says.
But not everyone is convinced. Futuyma points out that nature's experiment didn't produce exactly the same results on every island: Two kinds of lizards are missing from Jamaica and one from Puerto Rico. Still, says evolutionary ecologist Dolph Schluter of the University of British Columbia, it seems that at least in some cases, "history can repeat itself over and over."