SmarterThanHick
Senior Member
- Sep 14, 2009
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Second, I want someone to explain to me how evolution works, how is it propagated, what is the mechanism driving it forward? I'm especially interested in a coherent explanation of "Random mutation"
Third, have human beings stopped evolving? What's next, genetic prosthetics, clairvoyance, wings?
Evolution works through a process called natural selection, which is a fancy way of saying that natural pressures weed out less viable organisms and/or allow better adapted organisms to survive. The mechanism is the environment of the organism, which is why evolution tends to appear faster when environments drastically change.
Let's take the example of a bacteria. When exposed to penicillin, our model bacteria dies. Game over. But let's say our bacteria friend reproduces one million times, something it can accomplish in 20 divisions, which some bacteria can get through in 7 hours. Say it gets a random fluke mutation in its genes one in every 1000 reproductions. Now most of those mutations will be absolutely useless. Most will actually result in death. But some will appear harmless, and of no benefit to our friendly bacteria. Until. We expose it to penicillin again. This time, that seemingly useless mutation allows the bacteria to barely survive a small dose of antibiotic, whereas all of its brothers and sisters get completely wiped out.
How sad. One little bacteria all alone. With the mutation that just happens to save it from low doses of antibiotic. 7 hours later, it has a million offspring, and the cycle repeats itself. Perhaps a high dose of penicillin will kill the original saving mutation, but at that point, a new mutation has arisen that protects the offspring from even high doses, making it invincible to penicillin. Even if all its siblings get eradicated, it remains to repopulate with the strong genes.
This is evolution in a nutshell: random mutations creating non-random selection.
As you can tell from the example, mutations do not happen IN RESPONSE to events. They happen BEFORE the environmental pressure, but are strengthened and selected for by the pressure. So we don't get cool traits such as wings or clairvoyance just because we want it. There must be an environmental influence that selects for traits over generations.
Let me know if you have questions.