[ExI] IQ and beauty
danust2012 at gmail.com
Wed Oct 21 03:19:39 UTC 2015
On Mon, Oct 19, 2015 at 8:16 AM, John Clark <johnkclark at gmail.com> wrote:
> On Sun, Oct 18, 2015 at 10:22 PM, Dan TheBookMan <danust2012 at gmail.com>
>> The article is titled 'Female choice selects for extreme tail length in
>> This will only do for the species in question.
> One species example is enough. Nobody is saying that sexual selection is
> in fact I specifically said that generally sexual selection helps a
species. But like
> everything else about Evolution sexual selection is not perfect, it can
> like when a female uses the wrong rule of thumb to determine which male
to mate with.
It certainly sounded earlier like you were saying sexual selection is bad
in the peafowl example. E.g., you told us that they were "headed[sic] for
Yet peafowl are not listed as even endangered. That they're doing well
despite the males having huge tails should make anyone question what the
impact of huge tails is on survival. Yes, it likely has some negative
impact in some situations, but it's almost certainly counterbalanced by
other traits. (Then again, for many animals, merely appearing large can
scare off would be predators and intraspecies rivals. I don't think that's
the case here, but it would have to be tested -- rather than you and I
merely presuming we know because it's a cool story and some book we read
> The article describes an experiment, do you
> demand a experiment be
> performed on a extinct species? that would be rather difficult.
No, though the problem is when someone makes claims about a specific
species based on an abstract model when the evidence for that abstract
model isn't available or is shaky at best. In the case of Irish Elk, e.g.,
there's no unambiguous evidence that large antlers drove them to extinction
-- no evidence that makes us select the model of a runaway sexual selection
killing them off over things like habitat loss, inter-species competition,
or hunting by humans.
>> That's still a speculation with regard to the Irish Elk. There are many
theories of why it went extinct.
> And I would be astounded if the authors of any of those theories were
> to suggest that the size of the Irish Elk's antlers played no part in its
> especially when species of elk which have a large body size but much
> antlers survive to this day.
The main contending theories are ones that are neutral on antler size it
seems. I don't think this is foolish in any way. E.g., human predation on
Irish Elk wouldn't really factor in antler size. Humans at the time would
be using long-range weapons or other tactics that neutralize the antlers as
a deterrent, so large antler would have almost no impact on humans
harvesting the animals to extinction. What's more, humans likely would've
had no problem hunting herds, taking out females and young, and doing other
things that would quickly decimate these animals.
You might argue here, of course, that the antlers slowed the elk down, made
them easier to spot targets, or were so attractive to human hunters (who
wanted to collect the antlers), though humans also seemed to have little
problem hunting other animals. My guess here is it was a big animal with
lots of meat and material for use, making it a better target. Plus, simply
being larger, it probably had a longer time to maturation and was
socialized to defense against a different type of predator (ones that
fought short range). This is a speculation on my part, but it fits with
other reading of the actual data here. Remember, I'm sticking to the data
-- what we see in the fossil record -- and not to a just so story. The just
so story needs to be tested against data -- no merely accepted because it's
>> Why is not possible that range reduction and hunting by humans played a
>> much bigger role here than merely having supersized antlers?
> Human predation probably was a factor,
> I would be surprised if it wasn't,
> but the two things are not unrelated. Humans are no different from any
other animal, any predator would find that
> an animal with
> a 9 foot wide 90 pound grappling hook on top of its head would be a lot
> than hunting an animal without
> such an impediment.
No, humans would be very different from other predators -- even from
Neanderthals. (Of course, there seem to have been no Neanderthals around
7700 years ago, but when they were around they don't seem to have hunted
the Irish Elk to extinction, no?:) Other non-homo predators wouldn't have
the same kind of tools and coordination as humans. (Neanderthals, being
classified as homo, would have some of the same tools, but seem to have
been close in fighters and limited to a more forested environment. H.
sapiens seems to have been more adapted to steppe and broken forest, able
to roam long distances, better clothed, and faster breeding.) Humans would
be distance hunters with projectile weapons. This is far different than a
large cat, bear, or wolf -- all of which have to get close and risk serious
injury from their quarry. Gracile humans almost certainly would be no match
for an Irish Elk close in. So, I think we're talking about a very different
type of hunter entering the scene.
Also, in general, megafauna went extinction. Whether this was humans or
habitat loss (or a combo of the two) or something else remains an active
area of research, though it's telling that even megafauna without large
antlers went into decline and died out. This might tell us, if one accepts
the human hunting explanation that it was more simply being large --
antlers or no -- that made them more desirable and easier targets for
>> (If we're going to go back to the 1980s, e.g., check out this article:
>> http://www.sciencemag.org/content/228/4697/340 -- 'Taphonomy and
>> Herd Structure of the Extinct Irish Elk, Megaloceros giganteus.' Note
>> what the abstract states: adult males with small antlers seemed to
>> have died during winter segregation from females. What might that
>> imply, if true, about big antlers having an impact on survival?)
> It says "winterkill was the chief cause of death and was highest among
> juveniles and small adults with small antlers", well that is not
> During winter juveniles and adults of small body size almost always have
> higher death rates than larger adults, especially if the winter is
> cold as they were during the last ice age when the Irish Elk was alive,
> because physics tells us that small bodies lose heat more rapidly than
> large bodies due to the fact that small things have larger surface area
> relative to volume than large things.
Yes, though the takeaway here is we don't see large-antlered ones dying off
in these winterkills. Why?
> And we know for a fact that large
> bodied elk with small antlers survived the winters (and the summers)
> better than large bodied elk with large antlers because large bodied
> elk with small antlers are still around today.
Though these are different species and not as closely related to the Irish
Elk, so one can't be sure that's the reason they died off.
>> with extinct species like the Irish Elk. We don't have direct field
observations of their behavior.
> But we do have direct field observations
> of physics, enough to know that a 9 foot wide 90 pound anchor on top of
> a head is going to severely limit the movement of an animal,
> especially the movement of the
> most important part of the animal, the head.
> It is just not viable to maintain
> that the resulting huge increase in angular momentum of the head (never
mind the fact that the antlers would also hit things
> and further restrict
> movement) would be beneficial to a species.
Yet from this one would expect the winterkills to go the opposite way, no?
When the data doesn't fit the model, don't you question the model? The
thing is the male Irish Elk likely were otherwise adapted to have larger
antlers. These likely weren't just a spurious trait bolted on that dragged
the animal down to extinction -- in your earlier example of strapping on
large antlers to a modern elk or deer.
In fact, the shocking thing for you should be why the Irish Elk are
attested at all? The huge antlers, were they such a drag on survival,
almost certainly should've killed them off much sooner. Instead, the record
of Irish Elk is about 700K years long. It's not impossible, but it would
seem to be quite a lucky streak to last that long with such a deleterious
trait. (Of course, to be sure, any trait, in the right context, might prove
bad for survival, but that would go against the narrative of runaway sexual
selection doing in the Irish Elk, no? After all, the trait might have been
absolutely fine for survival or neutral regarding survival, but some other
factor came into play make it have a negative impact. But then the causal
explanation would have to account for that other factor rather than merely
cite runaway sexual selection.)
>> the experts here are not all lining up for big antlers did the Irish
> Can you find one single expert who maintains that gargantuan antlers were
> not a factor in extinction and if they were just a bit larger the Irish
> still be with us today?
The papers I cited were questioning just that, no?
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