Human consumption speeding up evolutionary change: study
Last Updated: Monday, January 12, 2009 | 6:22 PM ET
CBC News
Humans are dramatically speeding up evolutionary changes in the plants and animals they hunt and harvest, according to new research.
Researchers from Canadian and U.S universities analyzed data from a variety of studies that examined trait changes — like those in antler size or reproductive age — of 29 species of organisms consumed by humans.
The study found that changes in organisms harvested by humans — among them fish, ungulates, invertebrates and plants — occur 300 per cent faster than they would in the organisms' natural environment.
This is because humans generally tend to "target large, reproductive-aged adults," says the study, which will be published in Tuesday's edition of the Proceedings of the National Academy of Science.
"Fishing regulations often prescribe the taking of larger fish, and the same often applies to hunting regulations," said lead researcher Chris Darimont in a statement. (CBC radio's Jan. 17 edition of Quirks and Quarks will have an interview with Chris Darimont.)
"Hunters are instructed not to take smaller animals or those with smaller horns. This is counter to patterns of natural predation, and now we're seeing the consequences of this management."
Animals are also breeding at a younger age and are getting smaller, the study says. Populations of some fish are on average 20 per cent smaller than 30 years earlier while other creatures are reaching reproductive maturity 25 per cent earlier.
"The public knows we often harvest far too many fish, but the threat goes above and beyond numbers," said Darimont. "We're changing the very essence of what remains, sometimes within the span of only two decades. We are the planet's super-predator."
