Micro and Macro while fairly similar aren't exactly the same, and it isn't a matter of size or time scale. Microrganisms are well lets be fair aren't that slick in how they go about mutation. Hell it isn't even all that random. They often just pick up garbage they find lying around. Many of them when they find a piece of genetic code just incorporate it into their bodies. Doesn't matter where it comes from. You can literally bleed into a petry dish and in a week come back, and test the bacteria, and you will find human genes in their genome. The mutation isn't so much random with some bacteria, as it is driven by instinct. They naturally diversify even in the absence of radiation, or replicating errors. Many of them seem to even be fairly oblivious to their DNA.
This isn't a critique of Evolution. Just being fair here, because I know the creationists are basically ignorant about the terms they use in a vain effort to refute the evidence. Basically the plethora of bugs in the biosphere, aren't evolving at all as most people would understand evolution. Idiotically the creationist lobby just latched on to a defense that conceded a point they didn't need to concede. Pretty damning proof that they know they are full of it in my opinion.
Bacteria just mutate constantly as a survival mechanism. They aren't changing over time in response to the environment so much as they are mutating prior to environmental change. By constantly changing shit up they are basically ahead of the game. Unlike in Macro Evolution it isn't a try and fail venture. All outcomes are equally desirable. Further more it isn't even a linear progression. The bacteria just mutate in circles. They aren't getting more complex, or coming up with massively new mechanisms. Think of it more like changing clothing over and over and over again.
Don't get me wrong it is proof positive of Natural Selection. Just not in the way that the creationists obviously thought that it was. Had they just actually read rather then skimmed. They would have seen a logical counter argument. Beyond oh shit mutation making different things we are so fucked. Mutation in microbes isn't about random change so much as it is a active survival mechanism. Take a pond full of bacteria today, and test them against a pond full of bugs from three hundred million years ago, and you would find bugs with the exact same DNA. No it isn't that they did not change, but that they have gone full circle billions of times.
The fact that Bacteria basically don't give a shit about the genetic code they take in has been a boom for science, and frankly for industry. You can put any genes you like in the bugs, and you can have them churning out all sorts of drugs, and industrial chemicals. Kind of ironic that the study of Natural Selection is probably going to lead to cheaper drugs that can treat thousands of conditions in the future, because Microbes don't give a shit like their bigger cousins.
Just trying to keep it a little fair, and before Creationists make the argument for the sake of reason do a little reading on this subject. Seriously don't be so handicapped that a believer in Natural Selection has to present you with a logical defense to your side of the equation. Stop hiding in the corner.
