[ExI] ‘Survival of fittest’ is disputed

[The Avantguardian]

>From: Will Steinberg <steinberg.will at gmail.com>
>To: ExI chat list <extropy-chat at lists.extropy.org>
>Sent: Tue, August 24, 2010 10:52:12 AM
>Subject: Re: [ExI] ‘Survival of fittest’ is disputed
>
>Isn't "living space" an item in a subset of survival needs like food and water? 

> I fail to see how the ability to take advantage of living space is any 
>different than an ability which facilitates gathering or reproduction. 

If you are saying that claims as to the demise of Darwin's theories are 
exaggerated, I would heartily agree. Competing for living space is still 
competition. However, one of my college buddies from UCLA named Nathaniel 
Hallinan (now a doctoral candidate at UC Berkley) did a lot of work that is as 
of yet still unpublished in this arena. In brief, it is known from the fossil 
record that evolution is not a steady slow change in species but is instead a 
discontinuous process of long periods of stability punctuated with abrupt 
dramatic changes. This is called punctuated equilibrium and the mechanism behind 
it is informally called the evolutionary pump, or periods of alternating "feast 
and famine".

What my friend realized and called the "Eden hypothesis" was that the adaptive 
radiation phase of punctuated equilbrium, i.e. when you see scads of new species 
diversify from a given lineage, generally occured during periods of relatively 
easy living. During certain periods such as immediately after a mass extinction, 
competive pressures were minimal because there was lots "living space" so to 
speak. Because of this, exploratory mutations were penalized much less than they 
would be during periods of high selective pressure, when the environment is at 
carrying capacity. On the other hand, during high pressure phases of evolution, 
"fine tuning" mutations to maximize the efficiency of expoiting a particular 
niche were favored over any radical changes.

A good metaphor for understanding this is to think in terms of the fitness 
landscape as being an actual landscape of hills and valleys. Hills represent 
high fitness and valleys represent low fitness. Selective pressure can be 
thought of as the "water level" on the fitness landscape. During "hellish" 
phases, the water level is high, and you are better off climbing the hill you 
are already on to its peak and hope it is high enough in case the water level 
rises higher, rather than going down and potentially drowning. During "Eden" 
phases, the water level is low, and you are able to go down into the valleys and 
search around for other potentially higher hills elsewhere. Thus during "Eden" 
phases, many more "hills" become occupied and you get mass speciation or 
adaptive radiation.

That's Nat Hallinan's Eden Hypothesis in a nutshell. Now I gotta go.

 
Stuart LaForge
"Old men read the lesson in the setting sun.
Beat the cymbal and sing in this life, or wail away the hours fearing death.
Their choice is their fortune." - I Ching