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How Predictable Is Evolution?
sciencehabit (1205606) writes "If the clock rewound, would organisms evolve the same way they did before? Humble stick insects may hold the answer to that long-running question in biology. Through studies of these bugs, whose bodies match the leaves the insects live on, researchers have found that although groups of the bug have evolved similar appearances, they achieved that mostly via different changes in their DNA. 'I think it says that repeatability of evolution is very low,' says Andrew Hendry, an evolutionary biologist at McGill University in Montreal, Canada, who was not involved with the work."
Convergent evolution suggests it is somewhat predictable, unrelated species having evolved similar solutions to similar problems. If a solution is clearly better nature will tend to go there given sufficient time and experimentation (mutation).
The fact that a trait may be expressed by different DNA sequences doesn't really seem to undermine this. The DNA sequences are implementation details. Evolution is about solutions and environments not DNA sequences.
Looking at cows, dolphins and horses genetic proximity shows unexpected results, as cows and horses are not the closer in the trio, despite their similar features.
That suggests environment drives evolution in a predictable way, while the genetic evolution is not. This is the really amazing point: evolution find similar solutions to similar problems, but it does so through different ways.
no, a better example is - we handed the spec to a bunch of different developers...
They each gave us wildly different code to achieve the same goal.
If we give the same specs to other developers, we expect the same result. That the code will be wildly different each time for the same goal - so we can't predict what it will look like.
It's not that simple. Something like a blind spot can't just be evolved away. There needs to be a pathway from "has blind spot" to "doesn't have blind spot" that doesn't go through "vastly decreased eyesight" along the way. Otherwise evolution will stick with what it has, and no amount of selection pressure can cause it to change.
We're vastly suboptimal in many ways. We're not perfectly tuned machines, we're cobbled-together from evolutionary scraps, and you can see it by looking at any part of our physiology. That's precisely the thing that makes intelligent design a stupid idea. Yet, we "work", and are capable of survival, and that's enough.
A fool and his hard drive are soon parted.