Humans May Cause Evolution to Speed Up with Environmental Impacts

Humans may be speeding up the process of evolution. Scientists have found that human influence is causing some species to die off while others evolve quickly to take their place.

Just three years after crayfish were introduced to a B.C. lake, two species of fish that had existed in the lake for thousands of years were suddenly extinct. However, what took their place had researchers fascinated.

"When two similar species are in one environment, they often perform different ecological roles," said Seth Rudman, one of the researchers, in a news release. "When they go extinct, it has strong consequences for the ecosystem."

In this latest study, the researchers looked at the evolution that occurred in a B.C. lake. At one time, two species of endangered threespine stickleback lived in the lake; one lived in the middle of the lake and ate mostly zooplankton while the other lived closer to shore, eating insects there. In the mid-199s, though, crayfish were introduced to the lake. And between 1994 and 1997, the fish disappeared as a result of interbreedinig, leaving only a hybrid species.

The new species actually eats larger insects, so the amount of small insects around the lake have increased. In addition, leaves that fall into the lake now don't decompose as quickly as they used to.

"Much of Canada's biodiversity, particularly fish in lakes and rivers, are considered to be 'young' species that formed in the last 12,000 years or so," said Seth Rudman, one of the researchers, in a news release. "This type of evolution, known as reverse speciation, happens remarkably quickly and can cause alterations to the ecology of the ecosystem. It means we need to consider evolution in our conservation efforts."

The findings reveal how human impact can cause huge alterations in ecosystems, including the evolution of species.

The findings are published in the journal Current Biology.

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