Survival during treatment with an antibiotic is a substantial change that allows pathogenicity instead of eradication.
The ONLY way to explain how a bacterial population could develop antibacterial resistance through mutation, and why such mutations (or those gained via horizontal gene transfer) would be selected for as long as the antibiotic was in use.
There IS NO OTHER SCIENTIFIC EXPLANATION.
The only way to describe how bacteria gain antibiotic resistance and how it accumulates and persists within a population is the theory of natural selection of genetic variation.
There is no need for the bacteria to speciate or to change into something else for it to be the mechanism.
Your argument is as delusional as saying that unless a Planet or Sun formed, gravity didn't take place - because gravity explains how Planets and Suns form - so unless a Planet or Sun formed - it wasn't gravity.
Speciation is not necessary for evolutionary change to take place.
For example, changes in skin color did not make human populations into different species - yet evolution through natural selection of genetic variation is the only scientific mechanism that explains it.
“Speciation is not necessary for evolutionary change to take place.”
I don’t think anyone really has a problem that bacteria might mutate and in so doing achieve a level of resistance. If this is evolution, then we are all evolutionists. You win the semantics battle but do not win many minds over to believe that this mechanism can account for whole new complicated structures and functionalities. I have read somewhere (other than Seek and Find’s posts) that when a bacteria develops resistance through mutation, the gene that mutates really suffers regarding the function it serves to the cell. The bacteria survives but is less robust and contains no new information that puts the bacteria on the road to more complexity. Hence, bacterial mutation to allow survival cannot be used as an example of descent with modification.
RE: Bacteria need not become anything other than bacteria to exhibit evolution through natural selection of genetic variation, yet you seem fixated upon the delusion that it does.
Well then, we are simply using the term “evolution” in different ways. I see it as adaptation with its environment, with little siginifcant change, you seem to see it differently and then call people who disagree delusional ( is this the way you discuss things? This habit of yours seem to permeate this thread with other posters as well ).
But then of course we disagree.
If you simply suggest an awareness of on-going changes in pathogenic bacteria, I would concur. Bacteria do acquire resistance quickly, and many older drugs no longer work in hospitals and clinics.
But then I don’t see how this observation per se makes for instance, a Darwin Sceptic different from a Darwinian. Both are interested in finding new drugs that will work and seek to heal the sick.
A conclusion made by many scientists in experiments is that acquiring antibiotic resistance through mutation or horizontal transfer is “costly.” There is a tradeoff: for survival in a clinical environment (i.e., antibiotics prevalent), there is a metabolic cost in terms of slower growth. This is called antagonistic pleiotropy.
Antagonistic pleiotropy refers to the genetic expression of multiple competing effects, some beneficial, but others harmful to the organism. It often involves a case where reproduction and viability counter each other in biological fitness.
The gene provides a benefit in one circumstance, but has cost in another.
Don’t get me wrong, the results of various experiments do show that bacteria can change quickly. But although the we have acquisition of antibiotic resistance, I am not sure if we can call it Darwinian evolution.
All it does is demonstrate that bacteria were endowed to change and adapt very quickly in an almost constantly changing environment.
Bacteria have tremendous variability, yet there are limits to such change: the continuity, stability, and reliability of such bacteria are well known.