Study suggests humans can speed evolution
HUMAN INVENTIONS such as the Internet, mobile phones and fibre optic cable have increased the speed of communication, making it possible for someone to be virtually in two places at once.
It is no secret that life in the 21st century moves at a rapid pace. But can the rate of one of nature's most basic and slowest processes, evolution, be speeded up by humans?
That humans may have sped up the evolutionary clock for one species of fish is suggested by a study by J. Todd Streelman, new assistant professor of biology at the Georgia Institute of Technology.
`Lightning speed'
The cichlid fish of Africa's Lake Malawi, well known to biologists for their rapid rate of evolution, are estimated to have formed 1,000 new species in only 500,000 years, lightning speed in evolutionary terms, as it takes many animals thousands of years to form new species.
A fish exporter may have unwittingly set the stage for an evolutionary explosion when he introduced individuals of the species Cynotilapia afra to Mitande Point on the lake's Thumbi West Island. As of 1983, the species hadn't budged from Mitande Point. The fish had evolved into two genetically distinct varieties in less than 20 years when Streelman, then at the University of New Hampshire, Durham, and colleagues went to the island in 2001.
The study appears in Molecular Ecology.
Growing list
"This is a great example of human-induced evolution in action," said Streelman. "It adds to a growing list of cases, including introduced salmon, flies and plants, where human disturbance has set the stage for contemporary evolution on scales we've not witnessed before." The fish have evolved into two genetically distinct and differently coloured populations, one on the north side of the island, the other on the south, said Streelman.
These distinct markings may promote the evolution of new species as cichlid colour patterns are important in mate selection.
Streelman is eager to find the answer to the question whether or not that happens and how long it will take. "It could be that we'll have new species in another 20 years, although this depends on a number of factors. ''
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