July 19, 2013 — If you could hit the reset button on evolution and start over, would essentially the same species appear? Yes, according to a study of Caribbean lizards by researchers at the University of California, Davis, Harvard University and the University of Massachusetts. The work is published July 19 in the journal Science.
The predictability of evolution over timescales of millions of years has long been debated by biologists, said Luke Mahler, a postdoctoral fellow at UC Davis and first author on the paper. For example, the late Stephen Jay Gould predicted that if you "rewound the tape" on evolution and started over, you would get an entirely different outcome, arguing that small events -- a storm that wiped out a particular pond, a poor season for insects -- could have a disproportionate effect.
On the other hand, there are a number of examples of species in similar habitats that evolve independently into similar-looking forms, such as the cichlid fishes of African lakes.
"It's a big question in evolutionary biology, but very hard to test," Mahler said.
Mahler found his test subjects in the Anole lizards that live on four neighboring islands -- Cuba, Hispaniola (the countries of Haiti and the Dominican Republic), Jamaica and Puerto Rico. Anoles began colonizing these islands, all similar in climate and ecology, about 40 million years ago, and once there, they began to multiply, resulting in a diversity of species on each.
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