Super-Predators: Humans Force Rapid Evolution of Animals

Hunting and fishing by individual sportsmen as well as large-scale commercial fishing are also outpacing other human influences, such as pollution, in effects on the animal kingdom. The changes are dramatic and may put the survival of some species in question.

In a review of 34 studies that tracked 29 species across 40 different geographic systems, harvested and hunted populations are on average 20 percent smaller in body size than previous generations, and the age at which they first reproduce is on average 25 percent earlier.Dr Eric Palkovacs from the University of California Santa Cruz explains: "We have removed the large fish and that has a direct effect on the size structure of a population. Subsequent populations will feel that impact because those smaller fish contribute more genes to the population." In other words, the genes for "smallness" prosper while genes for "largeness" are selectively removed by fishing.

By hunting sheeps and elks with big horns and fishing large fish we are paying a "Darwinian debt" for generations to come.

http://www.bbc.com/news/science-environment-35462335

http://www.livescience.com/3224-super-predators-humans-force-rapid-evolution-animals.html