Posts by JackElder
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I agree, asexual replication doesn't mean there will be no copying errors. Perhaps it was Rich who was saying that?
No, you were very clear about this from the start - even in asexual reproduction there will be occasional mutations when the copying goes slightly wrong. But you seemed to be arguing that asexual reproduction would have an evolutionary advantage over sexual reproduction, as it wouldn't have the problem of mutations reducing the fitness of individuals. That's the position I was arguing against.
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It's not what drives evolution though. According to the theory at least - it's natural selection of replicators, not natural selection of replicators one generation down the line. Not sure where you got that from - and I'm not saying sarcastically, I'd like to know where you got that from. Perhaps I misunderstand you or the theory.
True; I guess I'm talking about the broader sense of inclusive fitness (as in, it can be a useful construct to think of an organism as "more fit" if its descendents are similarly more likely to reproduce). This is a theoretical framework to consider the general movement of evolution across generations. Because, of course, evolution only happens across generations - individuals live, possibly reproduce, and then die, and the resulting change to the gene pool is evolution. Any given individual themself doesn't evolve (except in relation to their ancestors or descendents).
But do you get my point about asexual vs sexual reproduction? I guess the point I'm making is that you seem to be arguing that asexual reproduction would avoid mutation and hence confer an advantage, but I think that one of the reasons that most species use sexual reproduction is because this isn't so. Even in species that are perfectly capable of reproducing asexually, the majority also still go through the tedious business of having sex to make babies as well.
Apologies if I've missed your point, but. ;)
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Evolution doesn't care about the population, nor about long term surviva of the species,
Evolution doesn't care any more than gravity does. ;)
it cares about the single organism's ability to reproduce one more time
No, what makes the difference is an organism's ability to have offspring that survive to be able reproduce themselves.
ence if it was somehow possible for a "stop mutating" mutation to develop, it would give an advantage to the carriers, and soon enough nobody would mutate anymore.
Only if the environment remained static. As soon as the environment changes - and the one thing you can guarantee is, the environment will change - a perfectly asexual reproducing being is going to be at a relative disadvantage to an imperfectly reproducing one with a greater variation in the population. Adaptation is inter-generational rather than intra-generational; the environmental change applies selection pressure to the population, and members more suited to the new environment gain a comparative advantage in survival/reproduction.
Plus: there's no such thing as absolute advantage/disadvantage in nature; it's all about how you're doing relative to all other organisms competing for the same resources. If everyone's the same, it's basically going to be a lottery; if everyone's just a little bit different, you can expect small relative advantages to be reflected in genetic change over time.
So I'm arguing that a purely asexual reproduction isn't adaptive. Even species that can reproduce asexually (say, most plants) also usually reproduce sexually, as it's advantageous to have some variation within the population.
[Disclaimer: I've been to a live Wiggles concert in addition to watching both Wiggles & Hi-5 on TV!]
We saw the Wiggles earlier this year. Best atmosphere at a concert I've been to in years. Standout moment was my five-year old turning to me in astonishment and saying "Daddy! They're REAL!"
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Yeah, OK, probably true, but aren't there a lot of goods we rich westerners buy which cause suffering elsewhere?
Indeed. When I read that, my first thought was that a lot of the negative consequences that Monbiot talks about are direct results of the prohibition structure. These things are not specific to drugs. For example, there's a lot of farmers in Tasmania growing opium poppies (Tasmania is the largest producer of legal opium alkaloids in the world, fact fans - http://www.regional.org.au/au/asa/2001/plenary/1/fist.htm), and I don't see that causing the kind of direct social ills to the growers and their communities that Monbiot mentions in connection with cocaine. Remove the prohibition, legalise the production, and you're left with people growing a cash crop with slightly interesting side effects. I'm sure there'd still be some abuses, but probably no more than already exist in the coffee or chocolate trades.
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Reproduction is a messy process, even for a bug, its imperfections are consistent with the elements of casuality that we find in other physical phenomena everywhere else in nature. And of course the vast majority of mutations are disadvantegeous, so there is no evolutionary advantage in the process being error-prone per se; in other words, if mutation itself was a characteristic that organisms were somehow able to lose, they would have by now.
A better argument is that imperfect reproduction is a good way of ensuring a range of physical characteristics within a population. Within a population, as long as the median physiological characteristics of the population cope nicely with the environment, you're fine. Outliers (individuals with atypical physiologies) will usually be less successful at reproducing, as you note. But if the environment changes, the presence of outliers enables the population as a whole to converge on the form most advantageous to the new environment.
Or: you don't want perfect, asexual reproduction all the time, because you need some variation in the population in case the environment changes. Yes, severe mutation is likely to be severely disadvantageous; but minor mutation isn't likely to be bred out too quickly.
This is just a point about how a minor degree of mutation can be adaptive when considered at a population level. Mind you, it's astonishing what's adaptive when you look at it at a population level. ;)
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... The Wiggles. BTW, am I the only one that finds it a little weird that, in a world prone to moral panics about child molestation, three rather creepy child-imitators are Australia's all-time top-grossing act?
No offence, but how much Wiggles have you watched? For one thing, there's four of them. Plus, the major strength of the Wiggles is that they don't imitate children - they are clearly depicting adults, who occasionally interact with children. And I have it on good authority that their special Wiggly gesture (extend forefingers on each arm, make rapid back and forth hand gestures) is intended specifically so that you can always see where their hands are when they're having photos with young fans.
I wouldn't sit down and watch The Wiggles for protracted periods by myself. But of the child-targeted media out there, I personally really rate the Wiggles as one of the better franchises. They beat the hell out of, say, Hi-5, who are genuinely a bit creepy and are sailing a little too close to the sexualisation of the presenters for my liking.
Don't mind me, I'm still hacked off about the upcoming redesign of Dora the Explorer...
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Funny, I never suspected you as being behind Whaleoil, Kiwiblog and Cactus Kate.
These would be his id in action.
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You see, you guys in the 70s had prog. Us children of the 90s had ambient - it's like prog, but with less lyrics, and more drum machines. Hands up anyone who owns the Orb's first two albums, or any of the longer works by the Future Sound of London? I still put ISDN on late at night to encourage people to leave parties.
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I've never (knowingly) heard any Yes, because the album covers scared me too much.
But I have a great fondness for Tangerine Dream.
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My favourite MJ anecdote is the apocryphal one that surfaced in popbitch a few years ago, about Quincy Jones' freakout during the recording of Billie Jean.