"William Morse"  wrote in message
> "Malcolm"  wrote in
>
> I beg to differ with you. I don't know what references you have for
> your  "classic response to heavy predation pressure",and I can
> understand how growing smaller is one response,  but it is very clear
> that one of the easy ways to establish a new niche that avoids an
> existing predator is to grow larger.
>
The problem is that predators prefer big meals to little meals, and a size
increase of a few percent is unlikely to lift you over the threshold from
prey to non-prey. So generally populations respond to heavy predation
pressure by becoming smaller, though there is a complicating factor, which
is that heavy predation reduces density, increases food supply, and creates
the conditions in which bigger body sizes can be achieved.

Here's the theoretical model.

Abrams PA, Rowe L
The effects of predation on the age and size of maturity of prey
EVOLUTION 50 (3): 1052-1061 JUN 1996

And here are two examples showing populations reducing size in response to
predation.

Reznick D, Butler MJ, Rodd H
Life-history evolution in guppies. VII. The comparative ecology of high- and
low-predation environments
AM NAT 157 (2): 126-140 FEB 2001

WELLBORN GA
SIZE-BIASED PREDATION AND PREY LIFE-HISTORIES - A COMPARATIVE-STUDY OF
FRESH-WATER AMPHIPOD POPULATIONS
ECOLOGY 75 (7): 2104-2117 OCT 1994

(I don't claim that you won't find any examples of the reverse response)
>
> I don't know what Dawkins would say either. The question of moral
> authority is in any case difficult. We can disqualify science, since it is
> only concerned with empirical questions. We must also disqualify
> religion, since there are many religions and they differ in many respects
>- they can only answer religious questions.
>
You are assuming that no religion has privileged contact with the divine.
This may be the case, but the existence of contradictory religions doesn't
disqualify the genuine, just as antibiotics aren't disqualified as medicine
because of crystal healing.
>
> We are left with coming up with a philosophical basis for ethics, which
> is not necessarily a bad thing to be left with, but  is also taking us
> outside of the charter of this newsgroup.
>
You can base ethics mainly on revelation from a super-human being, mainly on
reason, or on a mixture of the two, which is the position taken by most
religions in Western society. Since ethics concerns human behaviour, and
human nature, biology has an important supporting role to play. If we were
intelligent ants then our values would be completely different.
>
> In this respect it is also interesting to note that the shift from
polytheism
> based on personal gods of limited power to monotheism and/or
> remote gods, as described by a human prophet (Confucius, Buddha,
> Jesus, Mohammed) occurred on a global scale within a remarkably
> short time period, historically speaking.
>
This is probably something to do with technology. All these societies were
literate.
>
> Perhaps you misunderstood the significance of the reference to
> "detection of cheats and freeloaders". With this mechanism
in place, an
> individual who "works against the group" will be punished so severely
> that they will in fact be at a disadvantage.
>
No, I'm talking about what happens when the group hits a natural limit to
expansion. For instance, once all the monkeys on the island have green
beards, the genes for being nice to everyone with green beards cease to have
an effect.
You can of course get cheating or fissioning of a group well before it has
reached this limit, if it is possible to gain a local advantage by avoiding
detection.
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