Driving Evolution on Earth

Mounting evidence suggests humans are now a major driving force of evolution on Earth. From selective breeding to environmental modifications, we're altering so much of our world that we're not only now driving the climate, but the direction of life itself.

Now, in a massive project involving 287 scientists across 160 cities in 26 countries, researchers examined how urbanization has influenced evolution on a global scale. They used white clover (Trifolium repens) as a model – a plant native to Europe and west Asia, but found in cities all around the world.

"There has never been a field study of evolution of this scale, or a global study of how urbanization influences evolution," said evolutionary biologist Marc Johnson from the University of Toronto Mississauga (UTM).

Collecting more than 110,000 samples along gradients that extended from the cities, through suburbs and out to the country, they found that clover in cities is now more similar to clover in another city a world away than it is to that found in nearby farmland or forests, regardless of climate.

This is an example of parallel adaptive evolution – when separate populations are shaped by the same selective pressure for specific traits in different locations. It shows that the ways humans have changed the environment are having a bigger influence in shaping these traits than natural phenomena like local population genetics and climate.  READ MORE...