Discussion in 'Science and Technology' started by JBeukema, Sep 23, 2010.
How We Are Evolving: Scientific American
Another older beneficial mutation that has been very critical in some populations survival is the ability to digest milk as an adult.
I keep getting confused over this "mutation" business. You mean a gamma ray hit a cell and magically altered the DNA?
Well Frank, try thinking with your larger head.
Most mutations are not beneficial. However, given a large population, there will be a few that are. Sometimes, not even noticably beneficial, because the environement in which they increase the organisms survival chances is not the present one.
The mutatations can come about from many factors other than radiation. And lose the SciFi Movie mentality. Most mutations are very subtle, involving the way proteans work. Over long lengths of time, they do produce a differant specie, one that looks differant, and cannot breed with the parent specie.
If you really want to learn how evolution works, read Earnst Mayr and Stephen Jay Gould.
Mankind started dramatically changing the genome when we went from migratory hunter gatherers to a more collective system of farming.
First the genome changed because our diets changed, secondly since we lived closer together those with better immunity systems thrived.
The next major impact on the human genome began (and is probably still impacting it) because of industrialization. Since that system rewards those with superior mechanical skills, and those rewards insure a biofeedback system whereby those with those skills tend to do better, hence breed better than those without those talents.
Now we're rapidly approaching a technology where machines are doing out thinking for us.
Ironically, this might have the effect of dumbing down the average human genome.
Man is a social animal.
So as society changes, the genome of mankind is likewise effected over time.
It's a socio-bio-feedback effect.
Consider that the natives of the most primative place in the world (New Guini) actually have statistically significant higher IQs than people in industrialized world.
Because they NEED higher IQs to survive in that primative (and very violent) world of theirs.
I SUSPECT that their higher range and the rest of industrialized mankinds were once on a par, but the effect of civilized life (since we started farming and living in more dense demographics) makes people with superior auto-immune systems more likely to breed successfully than those with superior IQs.
Ironic, isn't it?
A primative man has to have superior intelligence and mastery over his society's every technology to make it.
We living in highly evolved societies mostly have NO mastery over our technologies and yet we can breed like rabbits.
rocky, that was not the way to convince anybody.
DNA is very complex, and does not copy over very well. the collapse of the copy system is one of the causes of aging.
From generation to generation, mutations in the copy mechanism make for differences in the genome. 99% of them are really bad ideas. Humans miscarry at a level of 40% of all pregnancies. Lots of mutations don't make it out of the oven.
Of those that do, the majority cause problems, but in the natural order, most of them die in a hurry. Prior to the 20th century, no more than 20% of children born in normal households survived to maturity. And lots of those who did, died in wars or famines. there is a huge selection pressure on the species, partly due to the fact that most of the human population lives far away from its natal areas. (And East africa is even more miserable for raising up a child in a natural state than anywhere else on the planet, what with lots of horrible parasites and large cats and dogs who regard us as lunch.)
So if you throw away 90% of the changes, the few remaining might be beneficial.
A good way to think of DNA mutations is like a poker hand. The average normal hand is say, for example, the King, queen, jack and 9 of spades and a nine of diamonds. It is a pat hand. In the world of evolution, you have to turn in a card. If you turn your nine of diamonds, and get a two, you are busted. You might get a nine of hearts or a nine of clubs, and you are back where you started. but if you get a 10, you have a winner, and if you get a 10 of spades, you are better yet.
You always have mutations. Most of the time, you bust. 'Sometimes you stay static, and sometimes you get real real lucky.
Magically? That would be creationism not evolution, Frank.
Alligators haven't evolved in over 300 million years, but man evolved in less than 3,000 years? You sure you have a solid grasp on this mutation business?
Aligators don't change because the pressure is on them not to change. You make a change, you don't survive.
Humans are in all kinds of weird environments. And we make our own. Human populations are spread all over the place. there are huge pressures that make for huge differentiations.
Alligators can't do much about the fact that they need hot temperatures and fresh water.
Humans are everywhere, and we are infinitely adaptable. But our environments all put different pressures on us which can cause large cosmetic changes in very few generations.
Let's not forget the Incredible Hulk and the X-Men.
I evolved once when I fell into a vat of toxic ooze!
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