Some of my fellow ScienceBloglings have written about Conservapedia’s treatment of evolution. What has always puzzled me about creationists is the rather frequent denial of mutation. For example, in the section on macroevolution, titled “Is the theory of macroevolution true?“*–which should tell you what’s to come right away, the entry reads:
2. Differences between organisms can be explained by known mechanisms of genetic mutation.
* Counter: There has not been enough time for mutation to generate existing biological diversity.
* Counter: There has been enough time enough time to generate existing biological diversity.
* Counter: The time argument doesn’t help. Decay, scattering, extinction, defects, disasters, etc., all INCREASE over time. Besides, all mutations are harmful.–Aschlafly 23:54, 21 December 2006 (EST)
All the ‘counter’ stuff is kind of bizarre, but anyway, what’s false (or is it counter…) is that “all mutations are harmful.” The short counter: antibiotic resistance. It would be impossible to even begin to describe antibiotic resistance without raising mutation; here are three examples:
1) Ciprofloxacin resistance. Most resistance to ciprofloxacin (commonly known as ‘Cipro’) is due to mutations in gyrases or polymerases. In the presence of the antibiotic, these mutations are quite beneficial (the bacterium doesn’t die). And over time, other mutations evolve that reduce or eliminate the harmful effects of these mutations when there is no antibiotic present.
2) The ‘range expansion’ of beta-lactamases. Huh? OK, beta-lactamases are enzymes produced by many bacteria that destroy beta-lactam antibiotics such as penicillin, methicillin (the “M” in MRSA), and many others. We have actually observed the evolution of newer beta-lactamases that are effective against many different beta-lactam antibiotics from older beta-lactamases that were (and are–many of them are still found in current bacterial populations) effective against very few beta-lactams (or even just one–penicillin). We’ve also confirmed this with laboratory studies.
3) The evolution of efflux pumps. Many bacteria have efflux pumps, which export nasty things out of the bacterial cell. Many efflux pumps are active only against heavy metals (which are toxic), but others can pump out various other compounds…including antibiotics. Both the amount of exportation, the effectiveness of exportation, and the ability to export a particular compound at all can be altered by mutations.
Of course, the biological reality, as opposed to the creationist fantasy, is that genes can expand their function by mutation and then be transferred to other bacteria, they can be transferred to other bacteria and then undergo mutation, they can mutate and not transfer at all, or a given gene can be transferred and not change one bit. But I realize that’s complicated. Ick.
One group of creationists wants to deny that mutations generate antibiotic resistance, so they can claim that mutations don’t do anything useful. As a result, they always play up gene transfer–the Intelligent Designer created all those resistance genes and they’re just shuffled around. The other group claims that antibiotic resistance evolves only through mutations because resistance gene transfer would destroy their notion of the immutability of ‘kinds.’
* What the hell is a theory of macroevolution, and how is it distinct from the theory of evolution by common descent (it’s not). Someday, I’m going to have to write that post about macroevolution….