Steve Schaffner wrote:
"Dylan" writes:
.. . . .

No, that's not what he means. Blind cave fish *might* have lost
their
sight because blindness made them more fit, e.g. if they were able to
redirect some resources previously used for vision. But they might
also have lost their sight because their fitness became independent
of
whether they had sight or not. If a trait does not confer greater
fitness, there is an excellent chance that it will disappear because
of random mutations.

--
Steve Schaffner

.. . . .

Suppose a population of fish gets trapped in a large cave with a large
body of water in complete darkness. At first they are all sighted. But
over time a blind percentage develops. Then, over more time, a
percentage of the blind percentage develops antennae that help them
better find food. Suppose, further, that at some point in time there
are three subpopulations of equal size: original sighted, evolved
blind, and further evolved blind fish with antennae. Now my questions:

1. Which subpopulation shows the greatest "survival of the fittest"?

2. Which shows the least?

3. And why?

Thanks in advance,

Dylan
%0

On 17 May 2005 10:48:06 -0700, "Dylan"
wrote:


Bobby D. Bryant wrote:
On Tue, 17 May 2005, "Dylan" wrote:


Bobby D. Bryant wrote:
On Tue, 17 May 2005, wrote:

survival of the fitest is based on chance.

SotF describes a _bias_ to chance.

Explain, Spock.

SotF means that those that are "more fit" are more likely to survive
and reproduce. Chance still plays a role -- even the fittest might
be struck by lightning before breeding -- but chance isn't the *only*
thing that goes into the determination of which creatures reproduce
and which don't.

I.e., SotF _biases_ the chance.

--
Bobby Bryant
Austin, Texas

Do you mean that cave fish that have evolved into blindness are more
fit than their ancestors?

They are better adapted to live in total darkness. So why would a
god decide to create fish with out eyes to live in darkness?

On Tue, 17 May 2005, "Dylan" wrote:

I didn't, I just find the "survival of the fittest" concept
fascinating, and I want to learn more.

I'm not too crazy about the term myself, mostly because lots of people
seem to read too much in to it. I prefer a very detatched point of
view, namely that some individuals/populations/species propagate into
future generations and others don't. Which do and which don't is
_partly_ a matter of chance -- asteroid strikes, dangerous new prey
moves in, climate change kill off food source, etc. -- but when all
else is equal, some individuals/populations/species are better able
to avoid certain problems and/or exploit certain opportunities, and
that gives them a statistical advantage in the roll of the die that
determines which propagate and which go extinct.

Fitness isn't an absolute; what's advantageous in one context might
be disadvantageous in another. But if you've got some trait that's
advantageous in some context, *and* you're actually in that context,
then you can reap the rewards for that advantage.


Your answer is helpful. Thanks.

You're welcome.

--
Bobby Bryant
Austin, Texas

On 17 May 2005 11:40:57 -0700, "Dylan"
wrote:

I didn't, I just find the "survival of the fittest" concept
fascinating, and I want to learn more.

Well first off, forget the idea that it means survival of the biggest
and strongest and fiercest. The example I like to use is the tiger and
the bunny rabbit. Which is fiercest and strongest? Which is an
endangered species likely to soon be extinct?

Fittest means best suited in some way to survive. In the case of the
rabbit this means an ability to run fast and reproduce rapidly. It can
mean having the right protective coloration or having developed a bad
taste predators don't like. It often means fitting into some
environmental niche better than other species.

Nor does failure to survive necessarily imply a defect in a species.
If a moist fertile area like North Africa used to be becomes a desert
with the retreat of ice-age glaciers, many species will not survive
the sudden change because they are not 'fittest' in a desert
environment.

See also: http://www.talkorigins.org/faqs/faq-...o-biology.html

## A mind stretched by new ideas
## can never go back to its original dimensions.

Dylan wrote:
Bobby D. Bryant wrote:

On Tue, 17 May 2005, "Dylan" wrote:


Bobby D. Bryant wrote:

On Tue, 17 May 2005, wrote:


survival of the fitest is based on chance.

SotF describes a _bias_ to chance.

Explain, Spock.

SotF means that those that are "more fit" are more likely to survive
and reproduce. Chance still plays a role -- even the fittest might
be struck by lightning before breeding -- but chance isn't the *only*
thing that goes into the determination of which creatures reproduce
and which don't.

I.e., SotF _biases_ the chance.

--
Bobby Bryant
Austin, Texas


Do you mean that cave fish that have evolved into blindness are more
fit than their ancestors?

That may very well be the case - the cost of building eyes is not insubstantial.

--
John S. Wilkins, Postdoctoral Research Fellow, Biohumanities Project
University of Queensland - Blog: evolvethought.blogspot.com
"Darwin's theory has no more to do with philosophy than any other
hypothesis in natural science." Tractatus 4.1122

In article ,
John Wilkins wrote:

Dylan wrote:
Bobby D. Bryant wrote:

On Tue, 17 May 2005, "Dylan" wrote:


Bobby D. Bryant wrote:

On Tue, 17 May 2005, wrote:


survival of the fitest is based on chance.

SotF describes a _bias_ to chance.

Explain, Spock.

SotF means that those that are "more fit" are more likely to survive
and reproduce. Chance still plays a role -- even the fittest might
be struck by lightning before breeding -- but chance isn't the *only*
thing that goes into the determination of which creatures reproduce
and which don't.

I.e., SotF _biases_ the chance.

--
Bobby Bryant
Austin, Texas


Do you mean that cave fish that have evolved into blindness are more
fit than their ancestors?

That may very well be the case - the cost of building eyes is not
insubstantial.

And a large part of the brain to support it. It's like those battle
tgames where you are given a number of points and are allowed to buy
attributes for you characters with those points.

There are more rats in NYC than humans. And I am sure more cockroaches
than rats.

--
Guns don't kill people; automobiles kill people.

Walter Bushell wrote:

.....

Dylan wrote:

.....

Do you mean that cave fish that have evolved into blindness are
more
fit than their ancestors?

[Someone wrote:]

That may very well be the case - the cost of building eyes is not
insubstantial.

Walter Bushnell wrote:

And a large part of the brain to support it. It's like those battle
tgames where you are given a number of points and are allowed to buy
attributes for you characters with those points.

There are more rats in NYC than humans. And I am sure more
cockroaches
than rats.

.....

Dylan writes: Point taken. Now can you give me an example - such as
long feelers - which might make blind cave fish more fit than their
cousins who are still sighted but have not evolved the feelers? I'm
suggesting feelers because while you (and others) have suggested that
the blind cave fish could well be better fitted because they could
transfer some of their energy budget away from building/maintaining
eyes to something else. The theory makes sense. Any real-life examples?
Any thought-experiment examples? I learn best by contemplating
real-life examples. Thanks.

On Thu, 19 May 2005, "Dylan" wrote:

Dylan writes: Point taken. Now can you give me an example - such as
long feelers - which might make blind cave fish more fit than their
cousins who are still sighted but have not evolved the feelers? I'm
suggesting feelers because while you (and others) have suggested
that the blind cave fish could well be better fitted because they
could transfer some of their energy budget away from
building/maintaining eyes to something else. The theory makes
sense. Any real-life examples? Any thought-experiment examples? I
learn best by contemplating real-life examples. Thanks.

Just a point of clarification, that "something else" doesn't have to
be a new feature. It could be stuff it needs to build anyway, such as
skin or scales or teeth or whatever. The point is that the sightless
fish needs less food and oxygen than it would if it had to support
eyes and visual areas of the brain, and the reduced requirements
themselves can be an advantage over an all-else-equal kind of fish.

--
Bobby Bryant
Austin, Texas

In talk.origins Dylan sanoi, hitaasti kuin hämähäkki:

cousins who are still sighted but have not evolved the feelers? I'm
suggesting feelers because while you (and others) have suggested that
the blind cave fish could well be better fitted because they could
transfer some of their energy budget away from building/maintaining
eyes to something else. The theory makes sense. Any real-life examples?
Any thought-experiment examples? I learn best by contemplating
real-life examples. Thanks.

It takes a lot of developmental and maintenance energy to
run eyes. But I don't think you need to go as abstract
as an energy budget. You probably increase survival by
having less blood and fewer nerve endings concentrated in
such a vulnerable area.

rich

--
-to reply, it's hot not warm
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
\ Rich Hammett http://home.hiwaay.net/~rhammett
/ "Better the pride that resides in a citizen of the world;
\ than the pride that divides
/ when a colorful rag is unfurled."

Any ichthyologists reading this? There are deep sea fish which have
developed long feelers as an alternative to eyes. Presumably they have
had longer to adapt to their essentially lightless environment. Some
deep sea critters, as you know, are bioluminescent. Perhaps in time
some cave animals would develop this. Altho, they'd all be blind by
then...

For once google fails me, for I can find nothing but vague references
to deep sea fish with feelers and useless eyes.

Kermit