Perplexed in Peoria  wrote or quoted:
> "Tim Tyler"  wrote in message
news:cfql3m$129r$1{at}darwin.ediacara.org...

[What does it mean to say that fitness increases in evolution]

> > However - there *is* a sense in which progress could be painted as an
> > increase in absolute fitness [:]
> >
> > Recreate a number of historical time periods, millions of years apart.
> >
> > Take a sample (using some sort of random sampling process) of organsms
> > from each time period - and test their survival in each of the other ones.
> >
> > The hypothesis that evoultion is progressive in character in the way
> > I suggest would strongly suggest that the later organisms would exhibit
> > better survival (over all the environments) than the earlier organisms
> > would.
> >
> > Such an experiment avoids the criticism that fitness must be evaluated
> > in the same environment before comparisons can be made - by evaluating
> > each organism in each environment. [...]

> [...] I am not sure that it is best to take the samples millions of
> years apart.  I suspect that this is something like defining Newtonian
> velocity - you get the best results in the limit as the delta-t becomes
> smaller.  A single generation is the best, or perhaps a small number
> of generations if you wish to smooth fluctuations.

The problem there is that - when considering small time intervals -
local fluctuations - i.e. noise in the data - can swamp the effect
you are interested in.

By analogy, if you are looking at the effect of the gulf stream
on the motion of plankton, you had better not sample *too* rapidly -
or what you will be looking at will be the effect of brownian motion -
rather than the effect of the gulf stream.

Sampling frequently might be OK - provided you took
a large number of samples to eliminate such noise.
-- 
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