Evolution takes time. Hundreds of generations are needed to separate favorable mutations and pass them through a population. That's at least on the order of thousands of years, if not millions, to ensure stability of a species. One of the reasons global warming is so threatening is that it is projected to take place over a relatively short time scale. For the most part, climate change in the past has taken thousands upon thousands of years to occur, giving rise to generational adaptations. Abrupt changes in the environment lead to mass extinctions. Global warming will happen in an eye blink in evolutionary time scales.
Have you seen squirrels cross a road by way of the overhead power line? The more direct route is faster and easier, but we know what the likely outcome of that choice is...squirrel genes are smeared across the pavement instead of being passed on to subsequent generations. Perhaps adaptive behavior is taking place. Deer, unfortunately, have yet to learn to walk that tightrope. The sudden arrival of highways and roads have created unnatural barriers still begging for adaptation in most animals. Perhaps one day, deer will not only learn to look both ways, but also suppress their penchant for being easily spooked, that natural survival trait which is now working against them (they frequently make the wrong decision when faced with oncoming headlights).
But what about homo sapiens? We are subject to the same pressures of natural selection, but we are also changing our "natural environments" at a mind-numbing pace. Besides developing a larger brain, the ability to walk upright set us apart from our ancestors. Nowadays, walking is no longer the preferred mode of transportation (at least in the U.S. of A.) Trains, planes, and automobiles allow us to sit for long stretches of time. Comparing pedometers, it is likely we walk one-tenth the number of steps as our founding fathers did...and they had the horse. So what's the evolutionary impact? "Fat ass" becomes a euphemism?
How's your eyesight? A lot of people wear glasses, contacts, or have corrective eye surgery. What selection pressure, then, is there to weed out these annoying genes? Short of mandating Buddy Holly eye wear, glasses can be a sign of intelligence, confidence, wealth, at sexiness - at least that's what I keep telling myself.
I think this is a great topic for speculation of how people will evolve. I imagine brain capacity will continue to grow as technology and the information age explode around us. As countries struggle out of poverty, their middle class will wait a little longer each generation to have kids. This will lead to longer natural life spans (as opposed to expected life span, which depends on living conditions, availability of medicine, stress factors, etc.) as well as weeding out genes that might fell a 30 year old...and later a 40 year old. I.e. cancers and "old age" maladies will be shifted to even older ages. But, new ills will present themselves to populations living beyond their natural life span. We see examples of this today in the form of arthritis, Alzheimer's disease, etc.
Then again, the biomedical field will outpace our ability to evolve these problems away. We can envision nanobots targeting and disposing of unwanted viruses, eliminating cancerous cells, repairing weak blood vessels, rejuvenating aging heart muscles, scrubbing neurons, optimizing body chemistry (whatever that means) - in short, we can imagine technology taking over the functions previously performed by the natural laws of evolution to make a better human.
But will it in fact be a better human or just the same human? When evolution grinds to a halt, will we look the same a million years from now as we do today? With questions like these rattling around in my head, I was delighted to come across
this article:
Evolution's end
Hay festival 2008: Could humans really have moved beyond biology's driving force?
The Hay festival's very own scientific rock star, Steve Jones, kicked off the first weekend with a provocatively-titled lecture on whether evolution was coming to an end for humans.
It was, perhaps, a risky proposition for a man who has built his career elegantly proving and communicating the truth behind Darwin's great idea. Evolution by natural selection irrevocably linked humans into the lineage of animals, negated the need for a creator and showed that we were as malleable as any life on Earth.
But no scientist can ignore the evidence piling up in front of him. To a packed auditorium, Jones wondered if our ability to cure diseases that would normally have killed us, the ways we move around the world, and our huge level of control over our bodies and our environments have conspired to take power away from the natural forces of evolution.
How do you think evolution of our species will be affected by technology? Is this where the evolution of the human being stops?
