Very Rapid Evolution in the London Underground

The future is always a rumor, and the past is always hearsay.

Over at Wired magazine, they note that while an excess of humans is killing off thousands of species, we are also creating some new ones too, a point I made back in 2005, in a post entitled Thinking About Species Loss in which I ruminated that,

It's worth remembering that even as we are losing species, we are also gaining them -- new types of chickens, pigs, apples, corn, and trees. New hybrids of canaries, geese, ducks, pigeons, cattle, horses, falcons, eagles, dogs and cats. And we are doing it with wild birds too.

The last time I flipped through a Sibley's Audubon guide to birds, I counted one extinct species of parrot (the Carolina parakeet), but 27 new species of introduced parrots that are found in wild flocks in the U.S. (65 species have been encountered in Florida alone). In California and Florida these wild-flocking parrots are already creating new hybrids. Wild parrot colonies are not just found in warm climates by the way -- they are found near my home in suburban Virginia, and in downtown parks in Seattle and Chicago. One hundred and fifty years from now my great grandchildren may find hybridized variations of these same birds listed as entirely new "American" species of parrots (the Sibley guide already notes the presence of many Amazon hybrids in Florida and California).

The theme is echoed in the Wired article, but with a very interesting example:

During World War II, Londoners often sought shelter from German bombs in the city’s subway tunnels. There, they encountered another type of enemy: hordes of voracious mosquitoes. These weren’t your typical above ground mosquitoes. They were natives of the metro, born in pools of standing water that pockmarked the underground passageways. And unlike their open-air cousins, London’s subterranean skeeters seemed to love biting humans.

Fifty years after the war ended, scientists at the University of London decided to investigate the subway population. They collected eggs and larvae from subway tunnels and garden ponds and reared both populations in the lab. The tunnel bugs, they confirmed, preferred feeding on mammals over birds. And when the scientists put males and females from different populations in close quarters designed to encourage mating, not a single pairing produced offspring. That sealed the deal: The underground mosquitoes were a whole new species, adapted to life in the subway tunnels people had built.

A whole new species! And created in less than 50 years! Amazing. And yet, as the article notes, is some variation of the phenomenon not occurring all the time?

The most obvious way that people create new species is through domestication. By picking out the traits in a wild population that are most beneficial to humans and breeding for them, people can “force evolution in different species,” [conservation scientist Joseph Bull] says. Wolves become dogs, nubby grass becomes maize, wild boars become pigs.

But humans can drive speciation in other, less purposeful ways. “It’s important to think about the creation of new species as a process,” Bull says. One of the most dramatic ways people put that process in motion is by moving members of an existing species from one place to another. Sometimes those individuals die in the new environment. Sometimes they hang on and interbreed with native species. And sometimes, they take over, like kudzu in the American South or snakes on Guam. Over time, the new environment exerts different pressures on the invasive population, causing it to diverge from its ancestors.

Right. Speciation is a process not an event, it is occurring all the time all around us, and at the raggedy starts and stops it's really a question of definitions. That said, how do the numbers add up? Are we creating about as many species as we are pushing off the edge to extinction?

Keeping these mechanisms in mind, Bull tallied up humans’ impact on species in a paper published today by the Proceedings of the Royal Society B. During the last 12,000 years, scientists have recorded 1,359 plant and animal extinctions. Meanwhile, humans have relocated 891 plant and animal species, and domesticated 743 —- for a total of 1,634 species. It seems that human-driven speciation could be as much a mark of the Anthropocene as extinction is.

Maybe. Who knows? Merely relocating a species does not create a new species. If that's the assertion made by Wired, then it's simply wrong. That said, there are so many types of chickens, turkeys, pigeons, sheep, goats, cows, horses, pigs, roses, marigolds, corn, soybean, tomatoes, potatoes, cabbage, wheat, rice, etc, that I suspect a very strong case can be made that, under some definition, there are More Species Now than Ever Before.

It's also almost certainty true that most of the new species being created (it's a process not an event) are going to be demonstrably more useful to humans than any of the species that have been wiped out, which tend to skew towards island-endemic birds.

The future, immediately ahead, promises a dramatic growth in species development thanks to leaps forward in the world of genetic modification. Bull notes that "Even in a region like Europe, where the use of GMOs in agriculture is relatively uncommon, there are 146 distinct variants of genetically engineered plant are approved or awaiting approval for commercial cultivation."

Of course, the battle between taxonomic "splitters" and "lumpers" is never ending.  That said, it is also pretty pointless.  It is what it is.  One can argue that a mosquito created in an artificial environment does not count as a new species, and that it is only a temporal "mutant" of an existing species, same as a dog is simply a wolf that took a wrong turn on the way to its den.  Whatever, and we shall see.

The velocity of change in this modern world is phenomenal, and it appears that it has never been as slow and clock-work-like as some would imagine.  Are we racing toward an apocalypse full of a few "weedy" species, or a bright new world in which there will be more species, and more useful species, than ever before? We shall see. Or not. It will be what it will be.

The future is always a rumor, and the past is always hearsay.