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While the tuatara holds the top speed record for evolution, scientists are beginning to make a list of runners-up. In order, below the tuatara, they are as follows: Adelie penguin, auroch, Mappin's moa, bison, brown bear, cave bear, cave lion, ox and horse. The new finding counters prior theories about what factors determine genetic evolutionary rates. For example, it was thought that animals that grew and matured quickly would have high rates. The tuatara, in contrast, can grow as old as 100 years and may only give birth after 10 to 15 years of age with offspring possible at two to five-year intervals. It was also believed that cold-blooded animals had slow rates of evolution. The tuatara, however, is cold-blooded, and can only survive in temperatures above 77 degrees Fahrenheit. "Many things (from the distant past) survived in New Zealand -- a survivor's paradise, I would say," Lambert explained. The tuatara is now rare and listed as vulnerable by conservationists. Although the discovery about the tuatara's speedy evolution goes against conventional wisdom, it supports a prediction made 40 years ago by evolutionary biologist Allan Wilson of New Zealand, who supported the then-controversial notion that "the rate of molecular evolution was uncoupled from the rate of morphological [body shape] evolution." Wilson even applied this approach to human evolution, something Lambert and his colleagues hope to investigate as well. "We want to go on and measure the rate of molecular evolution for humans," he said. "There are human mummies in the Andies and some very good samples in Siberia where we have some collaborators." Related Links: |
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