Wonderfulcross said:
gluadys said:
Just because evolution doesn't know that a certain mutation is needed doesn't mean the mutation won't happen. If it happens (and that's not a sure thing) then it will be of benefit to the organism in which it originated. At to its children, and to its grandchildren.
It can't just be any mutation.
Did I say it could be just any mutation? Of course not. It would have to be the mutation that was needed.
Sometimes they get a lucky mutation at the right time too
You are trusting in a theory that depends on a lucky mutation that only happens sometimes??????
The point is that mutations are occurring all the time. But nothing tells DNA which mutations are needed when. So a mutation may occur a million years before its needed, or 5 months before its needed or 30 days after the need arises or 5 years after the need arises or it may never occur at all. That is one of the things that is meant when we say mutations are random. They occur randomly in reference to need.
So our evolving giraffe population may already have the necessary genetic recipe for adapting to a longer neck length. But it wasn't developed earlier because it wasn't needed. Or a new mutation (or mutations) may occur after a slight lengthening of the neck so that the adaptation to longer neck length occurs in tandem with the growth of neck size.
Had the mutation not occurred either before or during the time-frame of neck-lengthening, then giraffes would still have short necks, because if they could not adapt to longer necks, longer necks would have been harmful and only short-necked giraffes would have survived.
Same reasoning applies to bacteria. If they are exposed to a new anti-bacterial agent, they must either depend on resistance they acquired earlier before it was needed, or they must depend on a new mutation occurring before they are wiped out. It has been shown that mutation rates tend to increase in situations of stress. This would improve the likelihood of the necessary resistance mutation appearing (just like buying extra tickets in a lottery improves your chances of holding the winning ticket.)
Either you worded that wrong or that is just the saddest most comical thing I ever heard of. Also, if this mutation happened only sometimes, explain how there are still more than trillions of trillions of trillions of bacteria on earth.
They breed fast. Ever see those commercials for mouthwash that show you how many bacteria are in your mouth before using the product and how few are left after you rinse your mouth?
What they don't show you is that about 20 minutes later the population of bacteria has recovered to where it was before you used the mouthwash. And the new bacteria all come from those few that survived your mouthwash--so they are born with the greater resistance their parents had. That's why anti-biotics have to keep changing too.
Of course even if you were right and the number of harmful mutations was much greater than the beneficial mutations, it would not matter. Ever hear of natural selection?
Yes I have. Now explain how that is relavent.
If you don't understand the relevance, you don't understand natural selection. What do you think the effect of natural selection is on a population in which there is a harmful mutation? What do you think the effect of natural selection is on a population with a beneficial mutation?
You also missed my last question. Why do mutations make life-span irrelevant when it comes to evolution?
If you truly read the rest of that, you would understand.
If you truly read the rest of that, you would understand.
Read what? The rest of your post? I already did. You were describing a sort of Lamarckian theory of evolution which has long since been falsified. So it is you who needs to improve your understanding of how evolution works.