Originally posted by: Frackal
Originally posted by: BrownTown
its easy to see evolution occur in small leaps in the type of time frame human minds easily comprehend. For example bacteria evolve resistance to drugs, to the point where they actually have specialized protiens in their cell walls that detect and pump out certain drugs. Now this is a complicated protien we are talking about with no purpose except to fight drugs, chemicals that 30 years ago didn't even exist, so obviously we are talking evolution here. The problem comes in expanding the small changes that can happen in a few years out to hundreds of millions of years. Peopls minds just find such lengths of time hard to grasp. And therefore it hard to understand how a very comlicated thing like an eye (obviously much more ocmplicated than a single protein) can develop.
Yes, very interesting, but doesn't it seem as though this is a directed process? I mean, it seems rather unlikely that random mutations within the last 30 years just happened to allow these bacteria to form the complicated proteins to fight off drugs
You have to understand the principle of "selective pressure". Random mutations are necessary, but the changes within the population are not.
For example, let's take drug resistance.
A population of 1'000'000 bacteria is exposed an antibiotic. The antibiotic disables the enzyme that supports the bacterial cytoskeleton. This antibiotic is so strong, that it will kill 99% of the bacteria in 30 minutes. However, due to random mutation, there is a small population of 100 bacteria (that came from 1) in the population, whose enzyme is 10X more resistant to the antibiotic. If the generation time for the bacteria is 30 minutes, then this is what would happen in the next few hours, assuming the antibiotic halflife is 30 minutes as well.
Minutes Resistant Bacteria Labile Bacteria Total Enzyme Activity Percentage of Resistant Bacteria
0_____100 999900 1000000 100.00% 0.01%
30____20 19998 20018 50.00% 0.10%
60____8 800 808 25.00% 0.99%
90____6 64 70 12.50% 9.09%
120___10 10 20 6.25% 50.00%
150___33 3 36 3.13% 90.91%
180___210 2 212 1.56% 99.01%
210___2684 3 2687 0.78% 99.90%
240___68719 7 68726 0.39% 99.99%
270___3518437 35 3518472 0.20% 100.00%
As you can see, in under 5 hours 100% of the bacteria are now resistant... and all it took was 1 mutation.