>This is exactly what selection for resistance to antibiotics has done for
>bacteria. In the 30's when penicillin was discovered, bacteria could not
>handle it. The random mutations in the bacteria eventually gave rise to a
>resistant form. Resistance began to be noticed in th 50s but it wasn't
>until the 80s that it began to become a real problem. While selection didn'
>t'look ahead' to that sequence o fdna which conveys resistance, the fact
>that bacteria which were closer to that sequence had an increased ability to
>survive forced the population in that direction. Today we hardly have any
>antibiotics which do what penicillin used to do.
Did the resistant form of the bacteria show up as a result of random
mutations, or were they already in the population and became dominant when
the non-resistant individuals were knocked off by the presence of
penicillin? Is there evidence that will decide this question?