Re: NANFA-L-- Kin Selection
Wed, 16 Feb 2005 12:17:51 -0700


> Wow! Lot of stuff in your note, Joshua. Yes, kin selection is a very sound
> theory, and is a part of modern evolutionary theory. But, regarding this:
> >Why do certain fishes, for
> > instance,
> > guard and protect fry that aren't theirs? They're related.
> The fish that guards another parent's progeny may just not have any mechanism
> built into it that can overide the guarding behavior in the presence of eggs
> or fry. In other words, the guarding behavior is elicited by the stimulus of
> eggs or fry in a particular setting. This certainly explains why some other
> animals care for babies not their own (witness even cross-species nurturing
> in some mammals). Do you know of data that show that a fish parent is more
> likely to guard the progeny of close kin than of individuals from an
> altogether different population, but same species?
Off the top of my head, I cannot think of any examples of studies relating to
tihs among fishes. And, there are weird examples that belittle the conclusion..
such as certain darters and sculpins moving into a used nest and rearing
offspring, simply because chicks dig guys with kids.

However, I can think of one study that showed that sculpins are more likely to
eat eggs and fry that are not theirs than they are their own... not quite teh
same thing. Among certain large cichlids, offspring set up a perimeter defense
around the parents nesting site, protecting the next generation. Among
primates, a female is much more likely to give care to an infant that is her
mother's offspring than her sisters, and much more likely to care for her
sister's offspring than a "strangers." Of course, no one's yet found that
aquatic ape, so.... :)

> Of course, it is possible that the behavior is not overridden because in real
> life situations in nature, any eggs or fry encountered are likely to be
> closely related.
I don't know if I agree with this, but it depends on how we regard closely
related. Obviously, there's an advantage to a species in protecting all members
of the species, regardless! (In fact, one of the more interesting ideas is that
there's an advantage to "preventing evolution," to kill of mutations.... the
last thing your species needs is to give rise to the Next Big Thing. . . talk
about competition. :)

> Regarding this:
> (of course, you have to believe in [Neo]Darwinian
> > Evolution
> > to begin with... but that's another matter).
> I don't "believe in" evolution. Instead I accept the theory as the best
> available scientific explanation of the facts as known. That's the way
> science works. We don't have beliefs. We have conclusions. Of course,
> among the facts to be explained are such things as the fact that the kinds of
> fishes on earth today are quite different from the kinds that were on earth
> back in Silurian and Devonian times! Some consider theories something to be
> "believed in," like having faith. Oh, well. Better drop it, the lists
> managers prefer that we not discuss such matters.
Ahh, now we're talking strictly semantics. I believe in the theory of
gravitation. I believe in the theory of a round earth. I believe that I am
here, in the science building, in my office,-in-my laptop, sending an e-mail. I
believe it's snowing out. I can't /prove/ any of it, but I have faith in it.
So, yes, I believe in evolution, I have faith in it, just as I have faith that
if I let go of my mug, it's going to hit the floor, all my tea is going to spill
out, and my office mate will give me a really funny look. To me,-in-a personal
level, my belief in evolution, science, and the conclusions I've drawn from it
are as strong and sound as anyone else's belief or faith in a deity (which I
will admit I do not share). It may not be the same kind of faith -- to believe
in a deity takes a certain kind of blind, innocent faith that I've regretedly
never been able to muster for anything.

The only great difference I see is that as I learn, and as we learn, my beliefs
shift and change... they're much more fluid than the beliefs a religion may
have. Five years ago, I believed natural selection was the single greatest
factor in evolution. I really thought so. So did a lot of people. Now, we're
starting to shift that belief as we reach new conclusions and see the importance
of Sexual Selection (which I currently believe to be the single greatest factor
in evolution), multiple-species evolution (i.e., the interactions of species
pressing evolution, more than a single effect on them), Kin Theory, and so

So, while there may have been a better word choice than "belief" overall, for me
personally, it's the best choice. :)

/ This is the discussion list of the North American Native Fishes
/ Association (NANFA). Comments made on this list do not necessarily
/ reflect the beliefs or goals of NANFA. For more information about NANFA,
/ visit Please make sure all posts to nanfa-l are
/ consistent with the guidelines as per
/ To subscribe,
/ unsubscribe, or get help, visit the NANFA email list home page and
/ archive-in-