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I'm listening to TED talks at work, currently Paul Ewald on creating gentler germs, by creating conditions that select for lower virulence.
Interesting stuff, and very clearly put -- if a parasite requires a living host for transmission, strains that quickly kill the host will die off. So, reducing opportunities for non-person-to-person transmition will create an evolutionary disadvantage for virulent strains. Cool!
Then I see this in the comments:
"But this is not domestication, this is out-competition. In other words, the organism did not ADAPT to be less of a severe pathogen, severe pathogens did not have any further advantage over milder forms."*
They forget to mention that severe pathogens actually have a disadvantage, because they incapacitate their host before the host can transmit infection.
The commenter is saying that what happens is NOT evolution...but it is, even by their own explanation. Evolution is not individual adaptation; evolution happens over populations. If the virulent strain in a viral population is "out-competed" to extinction, then the population has become less virulent.
On the happy hand, real discussion takes place in the comments! Woo!
Interesting stuff, and very clearly put -- if a parasite requires a living host for transmission, strains that quickly kill the host will die off. So, reducing opportunities for non-person-to-person transmition will create an evolutionary disadvantage for virulent strains. Cool!
Then I see this in the comments:
"But this is not domestication, this is out-competition. In other words, the organism did not ADAPT to be less of a severe pathogen, severe pathogens did not have any further advantage over milder forms."*
They forget to mention that severe pathogens actually have a disadvantage, because they incapacitate their host before the host can transmit infection.
The commenter is saying that what happens is NOT evolution...but it is, even by their own explanation. Evolution is not individual adaptation; evolution happens over populations. If the virulent strain in a viral population is "out-competed" to extinction, then the population has become less virulent.
On the happy hand, real discussion takes place in the comments! Woo!
no subject
Date: 2009-09-21 11:47 pm (UTC)From:The misguided idea that evolution is somehow "headed" somewhere or progressing, or that the current is nessecarily a flat improvement on the old, crops up again and again with those who don't understand the theory, but it wasn't the issue I was seeing here.
no subject
Date: 2009-09-22 01:02 am (UTC)From:no subject
Date: 2009-09-22 01:22 am (UTC)From:The most common seems to be the myth/meme of "Directional" evolution. It's kind of quasi-religious, and I think it's something we're kind of hard-wired to 'get', even though it's dead wrong. Of course, all those "Ape to man" t-shirts don't help...people who don't really bother to study at all wind up with this idea of evolution.
The second huge misconception I've seen more among the extremely religious: people who think that evolution = individual organisms adapting, rather than populations. I honestly thought that was so silly I never realized that some people honestly misconstrue the theory that way until I started encountering the writing of ID-ers. It seems too Pratchet-esque (keep dropping the turtle, eventually one will fly!).
By the way, I've now read farther down the comments, and while I still think they guy's argument was silly, there is informed discussion going on, and he does (later) get that evolution = traits becoming more/less dominant in a population, not individuals adapting.