So what if some type of stress leads to an increase in bacterial mutations?
Is that necessarily a “good” thing? Apparently, like a lot of other things, it should be done in moderation. Otherwise, overdoing it leads to “development of cancer and other genetic disorders in higher organisms.” Not exactly a recipe for onward and upward evo.
I think what’s really phenomenal is that, despite furiously mutating in response to the no doubt innumerable stressful periods experienced over the supposed 3 billion years, bacteria are still bacteria.
So, how does your linked article further the case of macro-evolution?
Well, Science has an explanation at the ready for why bacteria increase their mutation rate in response to stress, all you have is “so what?”. Hard to build up a system of reliable information on “so what?”.
Bacteria are still bacteria, they are also mitochondria and chloroplasts, they are enteric bacteria that we carry around in our gut to help us digest, bacteria are the natural fauna that cover our skin, bacteria are the reason why the first thing a newborn calf does is eat a piece of its mother's feces, so its own enteric bacteria culture can grow. Bacteria have evolved to occupy the most stressful conditions on earth, and have evolved to digest synthetic substances that were never present upon the Earth until humans invented them and mass produced them.
Every piece of evolutionary data needn't directly address the issue of “macroevolution” or common descent to show that evolution through natural selection of genetic variation is the mechanism whereby bacteria cultures adapt and evolve to stressful conditions.
But if your really interested in the data for common descent (or “macroevolution”) then check out ERV data. ERV’s are endogenous retroviral sequences that have incorporated into the genome. The interesting thing about ERV’s is that if you find one within a species’ genome that is very similar to an actual viral sequence it is likely only found within that species, or only in very closely related species EXACTLY as if it had incorporated itself into the genome very recently. And if you find an ERV sequence in a species’ genome that is highly degraded from the original viral sequence it is likely to be found in many different species in the same genus, EXACTLY as if it had incorporated itself a long time ago when all those species shared a common ancestor. Why would ERV’s form this system of ‘nested hierarchies’ other than common descent?
Once again Biology has an answer at the ready to explain this phenomenon, Creationist once again have no answer.