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Terreson Profile
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Punctuated Equilibrium


Here is a brief field note posted on a work night.

In a revision of the Darwinian theory of evolution there is a concept that delights the beejesus out of me. It is called punctuated equilibrium. It is the product of two then young paleontologists back in 1972. Classic Darwinian evolutionary theory holds that species evolution is gradual, cumulative, taking place over long periods of time. But in '72 two young turks in the science community (Nigel and that ever so chatty Stephen J. Gould) proposed a different model. In their terms evolutionary change appears in a single individual of a species, but rarely. Through natural selection (reproduction) a new trait gets transmitted to the enire species one individual at a time. Also because of the rules of natural selection an individual showing a desirable trait would get selected by her or his mate. But the (punctuated) phenotypical change gets followed by long periods of leveling (equilibrium), a stasis of sorts.

Observational work conducted on the Galapagos Islands over a period of twenty years, and involving a variety of finches, gives credence to the notion.

I've been loving this idea for a couple of decades. It absolutely romances me. And for two reasons. First, there is the notion that a single individual of a species is responsible for each and every evolutionary change. Secondly, and more poetically, I remember the first time I came across the concept. My gut reaction was immediate. I figured then and still do that every Romantic type personality can personally relate to the idea. All Romantics know that sudden life-altering change gets followed by long periods of leveling. The punctuated moment followed by the dry periods.

http://en.wikipedia.org/wiki/Punctuated_equilibrium

Tere

Last edited by Terreson, Jan/14/2009, 9:06 pm
Jan/14/2009, 7:40 pm Link to this post Send Email to Terreson   Send PM to Terreson
 
GaryBFitzgerald Profile
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Re: Punctuated Equilibrium


           Time

   Unfathomable Sea! whose waves are years,
     Ocean of Time, whose waters of deep woe
Are brackish with the salt of human tears!
     Thou shoreless flood, which in thy ebb and flow
Claspest the limits of mortality!

   And sick of prey, yet howling on for more,
Vomitest thy wrecks on its inhospitable shore;
     Treacherous in calm, and terrible in storm,
       Who shall put forth on thee,
          Unfathomable Sea?


- Percy Bysshe Shelley


Last edited by GaryBFitzgerald, Jan/25/2009, 5:09 pm
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Terreson Profile
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Re: Punctuated Equilibrium


Good stuff, Gary. I especially like the notion of dialogueing through poetry. They say the ancient Celtic bards did much the same.

Tere
Jan/15/2009, 7:14 pm Link to this post Send Email to Terreson   Send PM to Terreson
 


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