Honest question about evolution.. Bacteria vs. Penicillin

[banjosareunderrated]

No claims, no flames....Honest question for those in the know: how do strains of bacteria become immune to antibiotics without evolution? I've accepted the idea that in a population of billions of bacteria, only those few that are immune to penicillin would be left to propagate. That population would then be the target of amoxycillin, zithromax, etc.

Is this a fair argument for natural selection or not? If not, why?

thx.

[lenidog]

1. Well evolution and natural selection are intimately tied together

through natural selection you get evolution over eons of time.

[funflower]

2. I'm not a scientist, but

it seems to me that at least a higher percentage of the immune bacteria would reproduce relative to the number of non-immune bacteria that would reproduce, thus increasing the overall population of immune bacteria over a number of generations.

Antibiotic resistance seems to this amateur to be an example of the evolution of species that we can see during our own lifetimes, because, of course, bacteria generations are far shorter than human ones.

[longship]

3. Putting it simply

When administered, antibiotics do not kill all the bacteria. Those that survive have de facto higher resilience to the antibiotic than those which died. Subsequent offspring populations then have higher gene density for that trait. Over many generations this can give rise to populations which are completely immune to the antibiotic.

It's more complicated than that, but that's the basic deal.

[oscar111]

4. Its EVOLUTION IN YOUR BODY

right in your body.

fast, because bacteria generations are short.

i have read it put in just the words of my title.

AIDS viruses were the bugs spoken of.. how they become resistant.

other fast evolution... the moths of England's towns. during industrialization, white moths living on smokestaks.. the stacks became black with soot... only dark moths lived.. eventually the species became black.

also.. the crabs off Japan who came to look .. design on back.. like the outline of a deity the locals revered. they threw back in the water, crabs somewhat looking like the deity... till it got to looking very like the deity.

[izzie]

5. Does not breeding of animals fit into all this?

We may be doing it with force and because we like the results but it is done in front of us and we do see the results in one life time.Long time,Maybe-- in place of crabs just happening, but all the same it is some what the same. Then their is the 'inter-breeding' of races of people and they do change. Science can just about tell you what color eyes your kids will have if brown eyed people marry blue eyed people. This must fit into all this stuff.