It seems that you can't have a conversation about evolution that doesn't end with everyone involved feeling frustrated. You can't even mention the word 'evolution' without bringing up a political philippic, religious rant or scientific squabble. Unfortunately, this keeps everyone from the conversations that really matter - of course, I'm talking about the fun ones.
No, I don't mean the ones that are fun to paleontologists looking for the origins of limbs or biologists searching for the mechanics of fat accumulation. I mean the ones that are really fun, to just about everyone, save, perhaps, a die-hard creationist who is simply offended.
I say the past is soooo last-era. Let's think about the future! Too often we look forward with a glass-half-empty, doom and gloom attitude. So what if we're in the sixth mass-extinction event, and perhaps the largest, in history? If the past has taught us anything, it's that extinction is the norm, not the exception. After all, 99.9% of all species that have ever lived are currently extinct. And if those species hadn't gone extinct, we wouldn't have the species we cling to so strongly today.
The fun of evolution isn't in looking back - it's in looking forward. So let's take just one moment to release a barrel of monkeys into evolution and the future we're so upset about. Instead of the glass being half-empty, it's merely awaiting the next set of species to fill it. And what will those be? Ah, see! That's the fun part!
Who doesn't enjoy a lovely little flight of fancy every once in a while? Close your eyes and imagine the Earth in a few million years...
Peter Ward, a professor at the University of Washington, envisioned what might be in store for our planet in his book "Future Evolution." In his future, human activities have shaped biological diversity. Because large animals require space, they don't survive the ever-expanding human population. "It is visible in the rear-view mirror, a roadkill already turned into geologic litter -- bones not yet even petrified -- the end of the Age of Megamammals," he writes. Instead, super-survivors like rodents, weeds, crows and cockroaches diversify rapidly to fill in the remaining habitats - cities and cropland. All other animals will be directly human-created, including bioengineered food species (maybe like purple tomatoes?) and others kept alive or brought back from extinction to feature as exotic pets or theme park attractions.
However, I find it is a bit arrogant to think that in millions of years our species, out of all the species on the planet, will survive, let alone champion. With the possibilites of nuclear holocaust or any other number of ways we might kill ourselves off (let alone be out-competed), whose to say we're the ultimate survivors? After all, we've been around for what - 200,000 years? - nothing, compared to other species, and we're pretty fragile as far as organisms go, too. Douglas Dixon takes the opposite approach as Peter Ward in his books - envisioning a world after the extinction of man. In "The Future is Wild," a companion to a seven-part Animal Planet series, Dixon envisions the world over the next 200 million years unfolding in stages. 5 million years into the future is the next Ice Age (similar to his book "After Man"), full of larger than life rodents (are we seeing a trend?) and super-sized primate-eating birds. 100 million years from now, the Ice Age ends, a great sea covers much of the earth, and the temperature skyrockets. Antarctica is a tropical forest, where colorful birds and monsterous insects roam freely. Finally, 200 million years in the future a mass extinction eliminates most of the life on earth and the continents have collided, forming Pangea II. A colossal inland desert occupies much of Pangea II while the oceans are dominated by the ultimate predators, sharks, who prey upon colossal squid and flying fish that have adapted to fill in the niche of the extinct birds. Of course, in the forests that do exist live the terrestrial squid, who might evolve into 'intelligent' life.
If we do survive the test of time, will we not evolve ourselves? Imagine looking at a modern human from Lucy's perspective, and wonder what she would think of what her lineage became. She would be baffled by the complexity of our communications, amazed at how quick our minds are. And, OMG, look at our tools! How will our descendants amaze us? Or do you buy that they will they be the same as we are now, that humans aren't evolving? Biologists like Stuart Pimm and Ken Miller predict a homogenized human species, a UniHuman, with low genetic variability. Of course, if this occured, we'd be far more susceptible to a single catastrophic event drastically cutting populations or even splitting us into different species, like in Stephen Baxter’s novel “Evolution,” where an environmental-military meltdown causes humans to evolve into separate species of eyeless mole-men, neo-apes and elephant-people herded by their super-rodent masters (boy, everyone's high on the rodents). Personally, I think people value being 'different' and 'unique' too much to lose individuality and meld into a single, blurred race. If people gain the technology to choose their child's attributes, I picture people trying to make their kids 'special' - like punk rock pink hair or purple eyes. I think fashion might be less of what you wear but how you look - literally, from birth. Green skin or asian eyes will be fashionable at some point in the future like snakeskin miniskirts were in the 80's.
Of course, pharmacological and genetic improvements are becoming more and more feasible. Joel Garreau argues that these kinds of changes represent a new form of evolution. This kind of evolution moves much more quickly than biological evolution, which can take millions of years. In his book “Radical Evolution,” Garreau describes drugs and high-tech enhancements that could occur within the near future. He describes three different kinds of humans: the enhanced, the naturals and the rest - the enhanced are those who have the money and enthusiasm to do as they wish, the naturals will be those who 'stay true' for moral reasons (like today's Vegans), and then there’s the rest, who don’t get enhanced only because they can’t. The possibility is real - just ask Ramez Naam. His book, "More Than Human," explores what we already can do today, and what other options are not far off. Our future could be one full of 'PostHumans,' a species whose basic capacities so radically exceed those of present humans as to be no longer unambiguously human by our current standards.
Of course, technology could lead us down a different path, where the line between man and machine blurs out of existence. Who doesn't like a good cyborg? After all, we already have mechanical hearts and limbs. Is it really so far to stretch to think we might be able to install a computer in our brains to do math problems? Or like the image on the right, avoid the pain of pregnancy with our own internal incubators? We may end up creating entirely mechanic species- one that is capable of the core tenants of life: growth, reproduction and adaptation. Maybe political leaders will be debating whether robots should have rights, like in Bicentennial Man starring Robin Williams. We may even become the 'aliens' we fear may already be visiting us, once we have the technology to survive a lot longer and travel a lot faster than we can now, so we could make it somewhere else.
Of course, super-bacteria, resistant to every possible antibiotic, could take over and wipe everything out - making the world start at step one and evolve multicellular organisms from scratch. Hey, it's possible!
*sigh* I guess we can't spend all day in dreamland.
I don't know about you, but I find the future to be exciting, not depressing. I wish I could be the fly on the wall in the next few million years! Albeit we don't know if flies will survive... Well, you get what I mean. The next time you hear how such and such is dying out and on the brink of extinction, remember this: evolution is not dead.
That doesn't mean don't do what we can to conserve today. While we may sound noble when we talk about how terrible ecosystem shifts will be on other species, the truth is, we don't know if we can survive drastic global climate change. In human history, rapid climate changes like the Ice Age and warming around 11,000 years ago (Younger Dryas) likely decimated our European populations (for some review, see this essay). We might as well try and keep the status quo on Earth - it suits us well, which is how we've become so dominant. We may be the ultimate survivors, but, of course, I'm sure that's what the dinosaurs would have said at their height, too. The best motivation for us to cut carbon emissions or protect species may be entirely selfish.
In the end, if species do die as the environment changes, other species will be born from their ashes like glorious, unpredictable phoenixes. Who knows what the future holds? While it may not be the world we have now, there will always be a world - at least until we get knocked off our orbit or the sun explodes. With any luck, our species will be around to see what becomes of this mess we call Earth - but even if we don't, as they say, 'the show will go on,' and the world will evolve.
**UPDATE: This post was published in the Open Laboratory 2008! Go buy your copy!
**UPDATE: This post is up as a nominee for the 3 Quark's Daily Top Quark: Science! Go Vote For It Here!! (scroll down to the Os)