The unprecedented impact that humans are having on the planet is well known to us all. Scarcely a day passes by without a media report or two on the effects of human economic activity on the world’s climate or some charismatic species under threat because of illegal wildlife trade or logging.
Our impact on the planet is so profound in fact that some scientists are urging that our period in history be dubbed the ‘Anthropocene’, owing to the fact that humans have become the dominant influence on the planet, discernible even in the geological record.
But did you know that humans are now responsible for an explosive new shift in evolution? That the changes we are making to the planet have become so profound that we seemingly hold the evolutionary fate of millions of species in our hands?
Just what are these changes that are so profoundly shaping evolution? Pollution, eutrophication, urbanisation, land clearance, habitat fragmentation, global climate change, over-hunting/fishing, invasion by exotic species, domestication, emerging new diseases and disappearing old ones, to name just a few.
Many (probably all) of them are having evolutionary effects. Impacts that can be measured today, on contemporary timescales. Some of them are playing out on a global scale - such as anthropogenic climate change - while others are more local - including pollution and growing urbanisation.
Just how rapidly and profoundly our modern lifestyle and economic systems are shaping evolution is outlined in a series of scientific studies published just last month. New research by Marina Albert and her team published in PNAS and a set of articles just published in Philosophical Transactions of the Royal Society B leave little room for doubt that humans are responsible for a new and rapid burst of evolutionary change.
A few examples will help to illustrate the point.
It’s well known among biologists that commercial fishing has had a profound impact on wild fish species. By targeting large animals, as commercial fisheries have typically done, some species have become smaller and an increasing proportion have reached maturity at a younger age and smaller size.