From: Chris Taylor (Christopher.Taylor@man.ac.uk)
Date: Fri 20 Jun 2003 - 22:15:14 GMT
Goddamn I just wasted a lot of time waffling on about quasispecies. I
wish this list wasn't so high volume in some ways...
I think the difference is interesting between basins of attraction
(mostly from people talking about stable thermodynamic states
originally, and therefore not really a cultural influence as such), and
fitness peaks (an idea from an american, and affirmed by hard-working
protestants everywhere) where you 'strive'. This from Sewell Wright, who
was so intelligent, is so the wrong analogy to pick for blind nature,
and says a lot about the power of culture.
Cheers, Chris.
Dace wrote:
>>From: "Ray Recchia" <rrecchia@mail.clarityconnect.com>
>>Subject: Re: Precision of replication
>>
>>All of this gets back to Manfred Eigen's notion of 'quasi-species' which
>>can be identified mathematically using the concept of a multi-dimensional
>>fitness landscape. In a fitness landscape, higher points in one
>>dimension of the landscape indicate more reproductive success while lower
>>points in that dimension indicate lower reproductive success. Offspring
>>placed higher at the top of a fitness peak will be more successful than
>>those at the bottom. Because variation is constantly occurring, no
>>particular member of a species is exactly the same as any other but all
>>hover about the same fitness peak. Species then becomes defined by the
>>presence of a group of organisms sitting on a slope that is directed
>>towards the same local peak.
>
>
> Very interesting. What intrigues me about Eigen's model is that it's
> exactly the opposite of C.H. Waddington's model of development. Waddington
> also uses a hill to illustrate his point, except that in this case the goal
> is to go down the hill rather than up. Picture a hillside with many grooves
> ("chreodes") carved into it. If an embryo has gene A, it will take one set
> of grooves down the hill, and if it has gene B, it will take a different set
> to the bottom, where it will land at a different place, i.e. it will end up
> with a different set of characteristics.
>
> It makes perfect sense to envision evolution as an uphill climb while
> looking at development as a downhill descent. The reason is that evolution
> is a struggle to attain greater fitness in order to be environmentally
> selected. Development, on the other hand, is all about following the path
> of least resistance. You simply slide down the trail your ancestors blazed
> before you. To a limited degree, development is a recapitulation of
> evolution, except that instead of forging a path through struggle over many
> generations, an embryo merely follows the path already laid out. Evolution
> is all about creativity (the true "creationism"), while development is all
> about following ingrained habit. Individuals can be regarded as belonging
> to a common species when: 1) they reside on slopes directed to a common
> fitness peak and 2) their offspring descend through a common developmental
> pathway.
>
> Culture involves the same dual process. On the one hand, we create and
> promote ideas based on their fitness. On the other hand, when an idea is
> repeated enough, it becomes habitual, and our thinking merely follows the
> synaptic patterns already laid out for it. When a habitual pattern of
> thought is transmitted and becomes a culturally-shared habit, it's a meme.
>
> My point is that "habit" is the missing middle term in memetics. While a
> new idea must be consciously reconstituted each time it appears, a habit of
> thought takes on a "life of its own" and continues promoting itself long
> after its originator has consciously forgotten it. A meme, then, is simply
> a habit of thought that replicates across many minds as it becomes
> culturally ingrained.
>
> Ted
>
>
>
> ===============================================================
> This was distributed via the memetics list associated with the
> Journal of Memetics - Evolutionary Models of Information Transmission
> For information about the journal and the list (e.g. unsubscribing)
> see: http://www.cpm.mmu.ac.uk/jom-emit
>
-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Chris Taylor (chris@bioinf.man.ac.uk) http://pedro.man.ac.uk/ »people»chris ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ =============================================================== This was distributed via the memetics list associated with the Journal of Memetics - Evolutionary Models of Information Transmission For information about the journal and the list (e.g. unsubscribing) see: http://www.cpm.mmu.ac.uk/jom-emit
This archive was generated by hypermail 2.1.5 : Fri 20 Jun 2003 - 22:23:43 GMT