Has the environment (presence of antibiotics) stressed the bacteria population killing many of them? Yes
Do bacteria mutate? Yes.
Do some mutations make bacteria immune to some of these antibiotics? Yes
Has the genetic code been modified? Yes
Do other bacteria “descend” from these modified bacteria? Yes
Do they survive in the same environment? Yes
Could we say that this is descent with modification? Yes
Can the mutated gene still carry out its original function? Possibly, but probably (and in most instances) not as well
Are these mutations on the road to developing new genes for more complex biological functions? No - at least the ones we know about.
Are these bacteria on the road to ever being anything other than bacteria? No, not that we can tell.
Do these bacteria, with their mutations, environmental selection, descent with modification, prove that this mechanism can lead to greater biological complexity? No
Does this prove that uni-cellular organisms can evolve into multi-cellular organisms? No. Is this mechanism proven out to the point that we can say it is the mechanism whereby cold blooded creatures can modify and descend into warm blooded creatures; flightless creatures can modify and descend into winged creatures; creatures with gills can modify and descend into creatures with lungs; sightless creatures can modify and descend into the creatures with sight - complete with the brain functionality to interpret what they “see”; etc, etc. No.
The chasm is large. Time doesn’t help when there is no mechanism to result in the change needed.
The mechanism of mutation, selection, descent with modification has been proven for bacteria gaining immunity but has not demonstrated that it can lead to more complex biological functions, it is assumed that this mechanism can cross the chasm but never demonstrated. And to many of us, it seems a very poor, shaky assumption. — and this is the gist of the matter, semantics aside. The only thing we have seen descended from bacteria, fruit flys, and people are more bacteria, fruit flys, and people, whether changed, unchanged, mutated, adapted, “evolved”, etc.
THAT is why a bacteria has an error prone DNA polymerase with controlled expression during stress. To create that variation that selection will act upon.
The development of an enzyme that can digest nylon IS the developing of a “new” gene with a new complex biological function - and it was done using the EXACT SAME MECHANISM.
A bacteria becoming something other than a bacteria is no more necessary towards saying that evolution happened than a planet forming is necessary towards saying that gravity happened.
Evolution does not necessarily increase “complexity” either. Nor does it necessarily involve mutlicellular life arising from unicellular life.
But the mechanism is the same.
The “chasm” is quite small. Only a 2% genetic DNA and a 6% genomic DNA difference exists between humans and chimps. A rat and a mouse are separated by a larger “chasm”.
Now given that.....
1) DNA is the hereditary material
2) DNA cannot be copied with 100% accuracy
3) Variations are subject to natural selection
What is going to STOP this “descent with modification” such that over six million years a 2% genetic and 6% genomic DNA difference accumulate in separate populations?
What is going to stop it?