Re: Article: Big-brained birds less likely to migrate


"Robert Karl Stonjek" <rstonjek@xxxxxxxxxxxxxx> wrote in message
news:daghdu$23vg$1@xxxxxxxxxxxxxxxxxxxxxx
> Published online: 29 June 2005; | doi:10.1038/news050627-8
> Big-brained birds less likely to migrate
> Michael Hopkin
> Clever species stay put for winter, while others flee.
>
> It takes brains to make it through the winter, at least if you're a bird.
> A
> new survey suggests that bird species that have evolved to fly south for
> the
> coldest months tend to be those that weren't smart enough to survive if
> they
> stayed put.

On-going work with Avida has demonstrated that a digital species will not
diversify optimally where the supply of
energy (as in food) metabolizable by a species is overly abundant. Avida's
first trial version simply supplied everything (digitally speaking) and
anything needed by the digital species under observation. Evolution did
occur, but very slowly in that environment. Also, that species will not
diversify optimally where the amount of metabolizable (by it) energy is too
little for it to do more than survive. BETWEEN these limits, however, at
what Gould aptly characterizes as the Goldilocks level, optimal
diversification occurs. (I am trying to be as brief as
possible here, but not leave out bare essentials.)

This being borne out by computer-digital results, then, let us consider what
parallel might be found in nature.

There very conceivably could be a seasonal cycle wherein there are times of
the year when there is insufficient
energy (food, reward, or what have you) to go around but enough for a
significant number of individuals (with their own particular energy
requirements and metabolic functions) to survive quite easily, while
others -- if they remain --
will not have sufficient food they can metabolize or, if they are able to
eat the same food as (in this case) the
big-brained birds, would bring about their own demise and the big birds'
demise, as well.

Migration, in such a frame of reference, would be one of -- but not the ONLY
mutationally survivable factor. Only
when viewed in the context of the ENTIRE frame of reference is this seen as
a single possible move in a far more
intricate chess game, as it were.

Even here, I have omitted some qualifications without which the ENTIRE
significance of this is remote. Hopefully I have included just enough to
make a point without distorting it.

Another ISSUE is that there are many species without big brains that are not
merely surviving but, as William Faulkner would have it in his Nobel Prize
acceptance speech in 1949, they also PREVAIL.

To be abundantly clear as to what we might imply, or infer, with regard to
the survivability (or prevailability) of big-brained creatures, we must not
fail to account for the fact they seem on the whole to be fairing poorly in
the overall
scheme of Earth's general bio-frame, while many small brained (or hardly
brained at all) seem to be fairing quite nicely. Annelids, *** roaches,
bacteria, certain insects... seem, on the other hand, to be doing very well.

There seems to be a wide-spread assumption that large brains equate to
better coping capacity. But, while I must not set out the full argument,
the contrary COULD be argued in enormous detail.

Often in reading contributions to sbe, I perceive MANY things to be implied,
or hinted at, without being stated.

One can leave things dangling and not contribute any clarity. That is easy.
It also can be misleading and defensive... in that, if one begins to have
his intended meanings blown out of the water he can deny that was what he
meant.

It would help me to understand your intended meaning if you would state it.
If, for example, you mean to imply that the large brained birds are "better"
or "smarter" in some way evidenced by their not joining in the labor of
flying south in the fall... that would seem to me a difficult premise to
support. The birds that migrate -- at least prior to incursions by humans
upon the geography in which their food supply grows, which has no bearing on
the size of their brains -- were doing very well. There is abundant,
reliable documentation of the fact that migratory birds
literally darkened the skies over many parts of the United States as
recently as 100 years ago.

I am not sure on this but believe an issue crying out to be addressed here,
also, is one of a species' being able to
grow and sustain (energy-wise and metabolically) a large brain NOT requisite
to, but as a consequence of, having
an abundance of available food. I am not going to take that as a stance. I
feel confident Avida will bear it out, however. And I fully respect your
right -- if you so wish -- to say that Avida is not nature itself.

There are so many issues not clearly set out and considered here, which you
have not asserted clearly pro or con, that
there is no clear basis as to what might be argued about it. All I can hope
to do is suggest some issues that have not
been addressed by the above.

In time, I hope to have set out enough issues, FREE OF any argumentative
arena, that we might simply refer to them and say, in effect, "What about
these...?"

I hope this does not come off as being argumentative against whatever it is
you wished to imply, in your own mind.
It is not. It is more of a disclosure, on my part, that there are so many
issues not clearly stated in your comments that very little lends itself to
being challenged. I have done no more than guess what issues you may have
had a stance on... which you might have excellent facts and arguments to
support... that just didn't get addressed here. So this is
NOT a critique, but just a few observations based on guesses as to your
possibly underpinning, but unstated, primary assumptions and/or those of the
author of the article referred to.

Let me state an assumption of mine that I believe the designers and
upgraders of Avida would agree with:

IF THERE IS A WAY TO EVOLVE A CHARACTERISTIC WITHIN THE CONFINES
OF AN EVOLUTIONARY DYNAMIC -- EVEN THOUGH IT BE BUT ONE CHANCE IN
A MILLION OF
OCCURRING -- AN EVOLVING SPECIES, GIVEN SUFFICIENT TIME AND A
CONTINUING
PROPENSITY FOR AWARD, THAT CHARACTERISTIC WILL GET TRIED, AND
SUCCEED.

I do not pose that for argument but invite you to rip it to shreds if it is
wrong.

And, to that, let me add another bold statement of what SEEMS to me to be
valid:

THERE IS NO ONE WAY THAT ENERGY CAN BE PRESENT OR AVAILED OF,
IN AN ECOLOGICAL DYNAMIC, AND NO ASSURANCE THAT ONE SPECIES OR
CHARACTERISTIC
MUST WORK TO THE EXCLUSION OF ANOTHER. (This means that if a system
supports BOTH some
migration and some non-migration, there is no rule of nature -- spoken,
written, or tacit but applying -- whereby
the one is the "right" or "better," while the other is inferior.) If both
are working simultaneously and in a way that
is interactive or parallel (as over against destructive one of the other),
then that is a system which proves both are
pragmatically "right," in that context, at that time.



> The study shows that migratory birds, which leave temperate regions in
> search of warmer climes when temperatures start to dip, have smaller
> brains
> than those who stay behind. Non-migrating species also show more
> creativity
> when it comes to finding a meal in the frugal winter months.
>
> Daniel Sol of the Independent University of Barcelona in Spain and his
> colleagues used previous observations of 134 bird species in Europe,
> Scandinavia and western Russia. They collected data on brain size, and
> also
> counted the number of times researchers had spotted the birds adopting a
> novel feeding technique.

A POSSIBLE argumentive construction of these circumstances could be built
upon the supposition that the absence of larger brains in birds that migrate
is only HALF of the story. If the migratory birds, by virtue of their
having a given amount of energy-matabolic-dynamic allotment (under any
circumstances) must cash in a percentage of that
energy by way of kinetisthetics, while the non-migrating ones do not. I am
not unaware of the issue then raised as to why the non-migratory birds
"need" larger brains if they stay. If the larger brain enables them to
"think up" new and different sources of energy (foods) or "think up" ways to
burn less energy (in addition to not flying south) that still does not
establish that non-migration is "superior" as an adaptive alternative... but
only that it is capable of coexisting with other alternatives.

After all, the human eye, the eye of a fly, the eyes of a sand crab... each
is different, yet works as a variation that is
"permitted" within the Earth ecology context. Why not, then, BOTH migration
and non-migration? And why not
even more branchings of evolutionary diversification -- and simultaneously?

I am aware of the fact there are far MORE issues here than either of us has
addressed yet on this subject.

>
> Full text at Nature
> http://www.nature.com/news/2005/050627/full/050627-8.html
>
> Posted by
> Robert Karl Stonjek


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