Magus55 #fundie

Magus55 #fundie iidb.org

Very very bad example of evolution. The bacteria gets 'used' to the antibiotics and eventually becomes immune to it. Same concept as weight lifting. If you keep doing the same exercises over and over with no variation, your muscles will get used to the exercise and never increase. That and evolution is a process of gradual change over long periods of time, not a couple days in your school bio lab.

5 comments

old comment by David B.

@szena:

The same way we can get used to poisons like arsenic. If you are not exposed to a fatal dose, you can build up a tolerance over time.

Magus55 appears to be arguing that anti-biotic resistance is the result of a bacterium's increased tolerance to ABs in the face of weak exposure, combined with the asexual nature of bacterial division.

Unlike us, bacteria do not 'reset' their physiology from one generation to the next. The 'children' of a dividing bacterium will have the same biochemistry active in their cells as their parent as well as the same genome. Hence a reaction to a non-fatal exposure to antibiotics could be passed on in a very Lamarkian fashion.

But this is clearly not what actually happens. Analysis of the genomes of resistant and susceptible strains of the same bacterial phylotype show that the difference is genetic. Culturing resistant bacteria without antibiotics does not lead to a sudden reversion to susceptibility (just gradual genetic drift).

Magus55 is right that AB resistance on its own is a poor example of evolution, as (unlike in, say, fungicide resistance) a feasible alternative explanation can be given. However, he is wrong about how bacteria gain resistance, and wrong that evolution cannot occur over a couple of days, or in a school bio lab.

Magus55 #fundie iidb.org

5 comments

Confused?