You’ve got the right idea that animals tend to change to become better suited to their environments. Perhaps a population of humans could develop wings. We can imagine an awful artificial selection program, carried out by a dynasty of 'mad scientists’. Ignoring some complexities, a sketch of their dastardly plan might look like this:

Put a population of humans on an island, and enforce isolation from the rest of the world. At some point early in each male islanders life, he would be made to take a test. The test might measure the speed at which the boy can run up a steep incline (The ability to quickly run up inclines is hypothesised to have been a selection pressure that lead to the development of dinosaur wings). The bottom scoring 50% of the boys tested would be sterilised.

Over the generations, we would expect the incline-running ability of the islanders to steadily increase. Small mutations that made arms better suited to producing lift would quickly spread in the population and be passed to future generations. After many generations perhaps we might expect to see arms that were distinctly more wing-like. Perhaps they would have the beginnings of feathers, or a skin flap that would assist in pushing back air.

Once a distinct 'proto-wing’ was fixed in the population, the test might change to measure gliding ability, or vertical running, to further approach the ultimate goal of true flight.

You might notice that the conditions in the prehistoric world were very different from the experiment described here, and wonder how it was possible for flight to have evolved without the 'help’ of mad scientists. But the mad scientists were necessary only because we were interested in how to achieve a particular outcome (flight) relatively quickly. By contrast natural selection didn’t set out to produce flying animals at all, and was in no hurry for them to appear.

Posted: October 23rd 2009

See all questions answered by bitbutter

There are basic physical limitations that work against any organism of your size developing wings. If you double an organism’s length, height and width, its volume increases by a factor of 8. Its mass might not increase by quite that much, but it takes much more to support it. You can see this if you look at an elephant’s legs: they need to be incredibly thick, and therefore heavy, just to support the weight of the elephant.

You can see this with birds, too: the very largest (emu, ostrich) grew so large that they could no longer fly: if their survival had depended on flight, they would be extinct, but they survived, their wings became a hindrance subject to negative selection, and they shrunk.

So, if the human race ever shrinks down to a fraction of its size, and there’s a mutation that leads to them developing wings, and that proves beneficial, then yes, your descendants may one day have wings. Unlikely, but not impossible.

Posted: October 22nd 2009

See all questions answered by brian thomson

Not really a question about atheism, but I’ll try to answer.

Individuals don’t evolve. Species evolve, though it may take a long period of time and many generations (say, 100,000 years and 40,000 generations) to see big changes.

So, I think you’re stuck without wings.

Posted: October 22nd 2009

See all questions answered by Eric_PK

Natural selection is changes already present making the difference between an animal (or plant) living or dying more often than its neighbours.

You can’t force yourself to grow wings because the genome has no control over itself. It can’t make deliberate adjustments in real time. Besides, any adaptive changes you make won’t be written to your genome, and it won’t be passed on to your descendants either.

Let’s say you take your family and move to a commune in a set of treehouses, high up in a forest somewhere, and you all stay there for millions of years. Suddenly the ability to survive a big fall may well save lives.

That means that if people try to slow their falls by holding their arms out, those with longer arms and floppier arm skin will be a tiny bit more likely to survive and have more children who survive, all other things being equal. Every generation, the proportion of floppy-armed people would grow in proportion to the skinny-armed people, and the average outstretched arm width would increase.

After generations and generations, your family’s arms would be huge and floppy, and at least begin to look like wings. At no point would anyone’s body have deliberately tried to make the arm bones longer, or the skin stretchier. Whoever had the biggest arms in each generation, due to normal variation between individuals, had the best chance of passing on their genes. Being based on one lot of selection every generation, it’s a slow process.

The premier ongoing experiment in evolution today, run by Richard Lenski, uses bacteria. It produces results after thousands of generations, not just a few and certainly not within one. An individual cannot evolve, only adapt. If you want your own wings, make 'em out of cardboard.

Posted: October 22nd 2009

See all questions answered by SmartLX