Isn’t Darwinian evolution : “descent with modification”?
Let’s not talk about astronomy just yet, but antibiotic resistance.
Resistance to antibiotics and other antimicrobials is often claimed to be a clear demonstration of “evolution in a Petri dish.”
I will concede the word “demonstration”, but for me, the word CLEAR is too premature.
Analysis of the genetic events causing this resistance reveals that they are not consistent with the genetic events necessary for evolution.
Rather, resistance resulting from horizontal gene transfer merely provides a mechanism for transferring pre-existing resistance genes. Horizontal transfer does not provide a mechanism for the origin of those genes.
Spontaneous mutation does provide a potential genetic mechanism for the origin of these genes, but such an origin has never been demonstrated. Instead, all known examples of antibiotic resistance via mutation are inconsistent with the genetic requirements of evolution.
These mutations result in the loss of pre-existing cellular systems/activities, such as porins and other transport systems, regulatory systems, enzyme activity, and protein binding. Antibiotic resistance may also impart some decrease of “relative fitness” (severe in a few cases), although for many mutants this is compensated by reversion.
The real biological cost, though, is loss of pre-existing systems and activities. Such losses are never compensated, unless resistance is lost, and cannot validly be offered as examples of true evolutionary change. NOT YET.
So ribosomes with mutations resistant to antibiotics that targeted them existed before the antibiotics? Why, when they don't work as good as ‘wild type’ ribosomes? Why would they exist?
“never been demonstrated” is absolutely incorrect. Mutations to an enzyme that make the new antibiotic (based upon Penicillin) that previously didn't bind, now get bound and metabolized - as well as mutations that lead to the overexpression of said mutated enzyme - HAS been demonstrated. That is why Methocillin, that previously was immune to degradation by penicillinase, now has resistance present in some populations. Through mutation of the penicillinase gene.
So how do you explain why a bacteria would HAVE an error prone DNA polymerase, or why it would be expressed during stress?