Read more: 鈥�Unnatural selection: How humans are driving evolution鈥�
Humans are not only causing a mass extinction 鈥� we are also the biggest force in the evolution of the species that will survive
THE Zoque people of Mexico hold a ceremony every year during which they grind up a poisonous plant and pour the mixture into a river running through a cave (pictured below). Any of the river鈥檚 molly fish that float to the surface are seen as a gift from the gods. The gods seem to be on the side of the fish, though 鈥� the fish in the poisoned parts of the river are to the plant鈥檚 active ingredient, rotenone.
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If fish can evolve in response to a small religious ceremony, just imagine the effects of all the other changes we are making to the planet. We are turning grassland and forests into fields and cities, while polluting the air and water. We are hunting species to the brink of extinction and beyond, as well as introducing new pests and diseases to just about every part of the world. And that鈥檚 not to mention drastically altering the climate of the entire planet.
It is no secret that many 鈥� perhaps even most 鈥� species living today are likely to be wiped out over the next century or two as a result of this multiple onslaught. What is now becoming clear is that few of the species that survive will live on unchanged.
鈥淢any species will be wiped out over the next century. Of the ones that survive, few will live on unchanged鈥�
Far from being a slow process, evolution can occur extremely rapidly when the environment changes (快猫短视频, 2 April, p 32). So, as we alter the planet ever faster and more drastically, we are becoming the main force driving evolution. 鈥淭he intensity of the ecological effect of man is pretty obvious,鈥� says of Stanford University in California. 鈥淭here is an amazing amount of evolutionary change as a result.鈥�
Some of the fastest rates of evolution ever measured in the wild are in plants and animals harvested by humans. The few populations for which we have data are, on average, evolving three times as fast as populations subject only to natural pressures, for example.
Over the following pages, we look at the many ways in which plants and animals are already evolving in response to human pressures. Some of these changes, such as animals evolving to survive in highly polluted areas, can be seen as a positive thing. Others are bad from our point of view, such as animals we hunt losing the traits we value most in them, or pests becoming immune to poisons. What is clear is that whether the issue is growing enough food, conserving wild animals or keeping our beds bug-free, human-driven evolution is a factor we can no longer afford to ignore.
Read next article: 鈥�Unnatural selection: Hunting down elephants鈥� tusks鈥�
