Concerning Giraffes

[tapeh...@yahoo.com]

This is a question from a creationist friend...

If an animal's systems evolve only over a long period of time, without
any 'design', how did the animal survive, before all of the systems
were functional? Such as a giraffe's circulatory system? In short, why
didn't all giraffes die out before the little sponge-thingy in their
heads evolved, so as to soak up the gravity- fed blood flow before it
burst their brains?

[Boikat]

Incrementally. Does "your friend" think the giraffe's neck length
suddenly appeared, at it's present length?

Maybe "your friend" should study the litrature on evolution before
deciding he's found some flaw.

Boikat

[tapeh...@yahoo.com]

Not everyone is a troll..."Boikat"

[VoiceOfReason]

Here's one place to start.

http://en.wikipedia.org/wiki/Giraffe#Taxonomy_and_evolution

[Arkalen]

Basically, the key of evolution is that every step is functional.
Indeed, it's the constraint that every step MUST not only be functional,
but be a small improvement on the previous step that makes determining
how this or that feature evolved sometimes a difficult task.

That we don't know exactly by what path this or that feature evolved
isn't in itself a problem for the overall statement that evolution
happened and through what general mechanisms (mutation, natural
selection, drift) because there is a ton of other independent evidence
for those things.

Of course, knowing how every feature evolved is in itself an interesting
scientific question, the answers to which can even help shed some more
light on how evolution happens in general, even though it has nothing to
do with proving or disproving the theory of evolution as a whole.

As to your specific question on the giraffe's circulatory system, I
admit I find it confusing. How would gravity, which usually attracts
things in a downward direction, make the blood flow so as to burst
giraffes' brains ? (which tends to be on top of the giraffe ?) It sounds
like you're talking about an important feature of giraffe anatomy but
either you or your friend or me is confused on the specifics of how this
feature works.

As far as I've seen, those questions about how a mysterious new feature
appeared have two types of answers : either it turns out the mysterious
new feature isn't that new; it appeared by co-opting an existing feature
for a new purpose (like mammalian ears evolving from reptilian jaws, as
you can see from the bones), or it turns out not to be that mysterious.
For example, eyes really just start out as light-sensitive spots (and
molecules that react with light exist all over the place) and one can
build a smooth line of transitions from light-sensitive spot to cup
(which adds directionality) to deeper cup (improved directionality) to
pinhole camera (forms an image) to basic eye, every step of which is an
incremental improvement on the previous one and exists in the animal
kingdom. Similarly, your most basic sponge is a bunch of cells that get
their nutrition from directly absorbing nutrients in the seawater and
surrounding cells - all of the digestive and circulatory systems are
ways of making the process more efficient and adding surface area. The
basic process at work is still diffusion and osmosis.

So I suspect that if your spongy head structure does exist, it's either
a simple extension of the circulatory system, or it'll turn out there's
a similar structure in related non-giraffes that serves a different
purpose and was co-opted by giraffes to keep their brains from
exploding. Or, you know, both.

[Ron O]

On Sep 11, 4:57 pm, tapehead...@yahoo.com wrote:

The tape must have gotten erased.

Look up the giraffe's cousin the Okapi. What don't you get about
gradual evolution. A creation event would be more like what you are
thinking about.

Ron Okimoto

[r norman]

Others have already discussed this particular question -- that many
extreme morphologies involve simultaneous changes to a number of
physiological systems all of which can happen by a series of
relatively small changes each of which can convey increases in
fitness.

But I happen to have recently returned from a visit to Africa where I
had the opportunity to observe giraffes using their long necks and
great height for feeding. There is a theory that says the feeding
advantage is not at all sufficient -- why then are there not a lot of
other herbivores that show comparable adaptations? Why is the giraffe
unique? The answer was sexual selection because male giraffes use
their long necks in ritualized combat to determine mating hierarchies.
That part I couldn't observe directly -- I could see a wide variety of
browsing herbivores that appeared to my untrained eye to eat similar
foods but did not have the advantage of great height. Of course an
experienced field biologist would know the difference between
different species of vegatation and between young, tender, sweet
leaves and old, tough, bitter ones whereas I just saw animals eating
green stuff.

Incidentally, for the benefit of old-timers here --- while in Africa I
searched diligently for caves along the Zambezi River in Botswana,
Namibia, Zambia, and Zimbabwe. I found none. Therefore I cannot
refute the claim by my own direct observation that there are no caves
in Africa. That hypotheses must remain tenable from my observations.

[Garamond Lethe]

In a slightly earlier life I was interested in how text (and ideas)
become corrupted with copying. With that in mind:

Here's the question in a form that makes a bit more sense.

"Like the space shuttle, the giraffe is very well engineered.
It has a series of valves in its neck that allow its heart to pump
blood up to the height of its head, and without those valves its
brain would lose all its blood anytime the giraffe raised
its head to feed from trees, and it would faint and collapse. It
also has a special sponge-like organ that prevents too much
blood from rushing into its brain when it lowers its head to
take a drink. This organ is necessary because the giraffe's
body is quite high atop its long legs, creating enough down-
ward blood pressue when its head is lowered to blow the
delicate tissues of its brain apart."

Kenneth Lawrence, _The Evolution Delusion_, Xulon Press, 2008.

It has been asked before elsewhere.

"If evolution is true, then the giraffe is back to mindless,
totally random accidental chance processes, occurring over
long periods of time, to save its life and prevent it from
blowing its brains out every time it bends its head down to get
a drink of water. This evolution idea comes up short!"

Jobe Martin, _The Evolution of a Creationist_, Biblical Discipleship
Publishers, 1994;
citing Bob Devine, _God In Creation_, Moody Press, 1984.

"Without an exceedingly complex system to control pressure changes,
the brain
would hemorrhage and the giraffe would die when it bent over to
drink water."

Derrick Dean, _Is the Truth Out There_, iUniverse, 2003.


"When the giraffe lowers its head to drink or
eat from the ground, the high pressure of the blood racing to
its head could easily burst block vessels and cause the
animal to black out. .... Darwinists also do not explain
how genetic mutations, which are small and random,
manage these delicate orchestrations."

George Sim Johnston, _Did Darwin Get It Right_, Our Sunday Visitor
Publishing, 1998.


"Secondly, since giraffes like other animals get thirsty from time
to time, whenever they bent down to drink water, the process of
evolution through a series of uncontrolled random accidents would
have needed to come up with a mechanism for stopping block from
suddenly rushing into the brain to prevent the blood vessels in the
brain from bursting (leading to immediate death)."

Daniel Nyakundi, _Who's Telling the Truth_, Xulon Press, 2008



I hope you didn't find that too dull.

Having been around the block a few times, here's what I can conclude
from this rather tedious recitation:

1) Serious creationists aren't making this argument. You've probably
never heard of these people. I certainly haven't.
2) People who make arguments like this can't find even a second-tier
publisher. Creationist books by Dembski (Rowman & Littlefield) and
Behe (Simon & Schuster) sell well and top-tier publishers are willing
to publish them. Xulon is only a step up from a vanity press ---
sorry, my mistake. Xulon *is* a vanity press.
3) None of the folks quoted above gave pointers back to the peer-
reviewed literature. Nor (with one exception) do they cite each
other. This has the feel of an urban legend that "everybody knows".
[I'd appreciate a cite earlier than 1984 if anyone has one.]
4) I can't even find the giraffe story on Answers in Genesis or the
Institute for Creation Research. (To get a sense of arguments that
are so bad that AiG discourages their use, see:

http://www.answersingenesis.org/get-answers/topic/arguments-we-dont-use

So, we've got what looks like a bad, rare argument being made by
creationists on the fringe of the movement who are not familiar with
the scientific literature.

Now, why is it bad?

1. Evolution isn't random. Mutations are random with respect to
fitness. Selection on the results of those mutations is anything but
random. When you see verbiage like "mindless, totally random
accidental chance processes" you can be certain that the author does
not understand evolution well enough to describe it.

2. That "little sponge-thingy"? It's called a "Rete mirabile".

http://en.wikipedia.org/wiki/Rete_mirabile

Bird's got 'em. Tuna got 'em. Dogs got 'em. And you (if your of the
testes-carrying persuasion) have one as well. Is it some magical
device? No, it's merely blood vessels lying close to each other.
Knowing that, it starts to look less like a miraculously created organ
and more like a feature that relatively easy for vertebrates to
evolve.

3. We have a pretty decent fossil record of giraffe evolution. We
certainly have no evidence that there was some miraculous leap in
functionality.

"Giraffes: Branched off from the deer just after Eumeryx. The first
giraffids were Climacoceras (very earliest Miocene) and then
Canthumeryx (also very early Miocene), then Paleomeryx (early
Miocene), then Palaeotragus (early Miocene) a short-necked giraffid
complete with short skin-covered horns. From here the giraffe lineage
goes through Samotherium (late Miocene), another short-necked giraffe,
and then split into Okapia (one species is still alive, the okapi,
essentially a living Miocene short-necked giraffe), and Giraffa
(Pliocene), the modern long-necked giraffe."

http://www.talkorigins.org/faqs/faq-transitional/part2c.html



In closing: Your friend has relied on authors who mischaracterize
evolution (perhaps unintentionally), who are not familiar with the
basics of anatomy and who have not examined the fossil record.
Unsurprisingly, they conclude that the giraffe must have appeared via
some deus ex machina. Perhaps as late as 1850 this could have been
considered a respectable position, but now it's simply an argument
from ignorance: because *they* are unable to imagine how God might
have used evolution in creating the giraffe, and since their God is
certainly no smarter than they are, miraculous creation is therefore
required.

This is not a scientific argument, so calling it bad science rather
misses the point. But it's terrible theology: they circumscribe
God's abilities with their own limitations.

If you're at all curious about giraffe evolution outside of a
theological context, I highly recommend Craig Holdrege's essay "The
Short-Necked Giraffe".

http://natureinstitute.org/pub/ic/ic10/giraffe.htm

[Boikat]

That remains to be seen.

Boikat

[Ron O]

On Sep 11, 7:06 pm, r norman <r_s_nor...@comcast.net> wrote:

I was visiting the San Diego wild animal park and they have the
giraffes running around in a very large area. Two males started
fighting and it was very violent and you could hear the collisions of
the necks from where we were on the tram (a couple hundred feet).
When they struck both necks would wobble like they were made of a
stiff rubber.

Ron Okimoto

[Darwin123]

On Sep 11, 5:57 pm, tapehead...@yahoo.com wrote:
> This is a question from a creationist friend...
>
> If an animal's systems evolve only over a long period of time, without
> any 'design', how did the animal survive, before all of the systems
> were functional?

Because their necks weren't as long as they are now. The necks on
average were only a little longer than in the previous generation. The
distribution of neck lengths was and is rather wide. Only the average
shifted by a very small amount.

> Such as a giraffe's circulatory system?

Please note. That "little spongy thing" is made out of blood
vessels. It is not made of anything that anyone could call a
transformative change.

> In short, why
> didn't all giraffes die out before the little sponge-thingy in their
> heads evolved, so as to soak up the gravity- fed blood flow before it
> burst their brains?

The probability of fainting probably increased a little bit
when the neck size grew a little bit. The chances that an animal dies
increases a bit if the probability of it fainting increases a bit.
However, not all animals with a slightly longer neck will die.
There is a trade off in danger. An animal that faints more
often has a risk. An animal that can't find food is at risk.
Apparently, at the time there was a bit more of a risk not finding
food than of fainting. So the average neck size increased a bit.
After the neck lengthened on average not all animals were at
equal risk in fainting. Those animals with a few extra blood vessels
in their necks fainted less. So the percentage of animals with extra
blood vessels increased.
Those animals with a slight thickening of blood vessels in the
neck probably fainted less often. The ones that didn't have a extra
blood vessels were slightly less likely to die.
This alternates, generation after generation. Slightly longer
neck, slightly more blood vessels in neck. After many generations, the
average length is very long and the extra blood vessels form a
"sponge."
Animals are not so fine tuned that all animals drop dead with
the slightest variation from average. Furthermore, there are no small
variations that don't have both advantages and disadvantages.
An animal that has a long neck but faints occasionally may move to
an area where he can find more food. If the grasslands are overgrazed,
maybe the slightly long necked okapi may decide to move to a more
bushy area where his neck provides him an advantage. The other okapi
may as well stay where they are, because short necked okapi don't work
out in bushy areas. Once the long necked okapi are entranced in the
bushy area, a few with more blood vessels in the neck may be at an
advantage because they don't faint as often.
So step by step, generation by generation, a long necked okapi
with a blood vessel sponge in the neck develops.
If you think animals drop dead with even small variations, then I
can't answer. If you don't think that one small variation can
compensate for another, I can't answer. If you think things can
develop one step at a time, then I can answer.
Erosion doesn't happen in a day. Neither does evolution.

[Dakota]

I cannot refute the claim that you observed no caves in Africa. However,
a Google search on keywords "african caves" returned over 32 million
hits. The link below contains the following:

Day 4 Zimbabwe – Chinhoyi Caves

In the morning there is a transfer through the Lower Zambezi area and
back to the truck. All together again, we will pass through the Chirundu
Border (sometimes a time consuming process) and re-enter Zimbabwe. From
Chirundu it is not a long trip to Chinhoyi. Probably best known for cave
diving, the Chinhoyi caves system is the largest publicly accessible
cave system in Zimbabwe and reputably a ‘mysterious’ area.

http://preview.tinyurl.com/3lycrpz

[Stanley Friesen]

Arkalen <ark...@inbox.com> wrote:

>On 11/09/11 22:57, tapeh...@yahoo.com wrote:
>> This is a question from a creationist friend...
>>
>> If an animal's systems evolve only over a long period of time, without
>> any 'design', how did the animal survive, before all of the systems
>> were functional? Such as a giraffe's circulatory system? In short, why
>> didn't all giraffes die out before the little sponge-thingy in their
>> heads evolved, so as to soak up the gravity- fed blood flow before it
>> burst their brains?
>

> [snip ...]

>As to your specific question on the giraffe's circulatory system, I
>admit I find it confusing. How would gravity, which usually attracts
>things in a downward direction, make the blood flow so as to burst
>giraffes' brains ? (which tends to be on top of the giraffe ?) It sounds
>like you're talking about an important feature of giraffe anatomy but
>either you or your friend or me is confused on the specifics of how this
>feature works.

The actual issue is when the giraffes lowers its neck to drink, or to
fight another giraffe. The high blood pressure (380 mm Hg) necessary to
push the blood up 4 meters is then far, far too high for the brain to
handle. The structure which regulates the pressure under these
conditions is called a rete mirabile. Many animals have, independently,
evolved retia mirabilia in various parts of the body, for various
regulatory purposes. Such a structure is not an all or nothing thing. It
is a mode of organization of blood vessels which can start out imprecise
and small, and improve in efficiency over time. Given that the giraffe's
neck did not evolve particularly rapidly, there was plenty of time for
the new rete mirabile in the neck to develop and grow in synchrony with
neck length. [I wonder - it _may_ be that the giraffe's closest living
relative, the okapi, has a less developed cervical rete - does anybody
know the answer here?]

>
>So I suspect that if your spongy head structure does exist, it's either
>a simple extension of the circulatory system,

A fairly simple reorganization of the circulatory system, actually, as
it is fundamentally just a set of fine arteries and veins arranged close
together, in an approximate countercurrent orientation.

> or it'll turn out there's
>a similar structure in related non-giraffes that serves a different
>purpose and was co-opted by giraffes to keep their brains from
>exploding. Or, you know, both.

Laso possible - retia mirabilia perform various functions:
thermo-regulation, osmotic regulation, oxygen exchange and so on.
--
The peace of God be with you.

Stanley Friesen

[Mark Isaak]

Darwin answered that question in _Variation of Animals and Plants Under
Domestication_. Direct your creationist friend to read it.

--
Mark Isaak eciton (at) curioustaxonomy (dot) net
"It is certain, from experience, that the smallest grain of natural
honesty and benevolence has more effect on men's conduct, than the most
pompous views suggested by theological theories and systems." - D. Hume

[r norman]

On Sun, 11 Sep 2011 20:19:51 -0500, Dakota <ma...@NOSPAMmail.com>
wrote:

That web site indicates the cabes to be in a "mysterious" area. If
you want to believe unreferenced third-party gossip, then that is your
decision. I can only report on what I know to be true from first-hand
experience. And from my own observations I cannot say that there
definitely exist caves in Africa.

[Jeffrey Turner]

I can understand why you didn't want to find a cave in Africa. You
might have run into one of these:

http://www.google.com/imgres?imgurl=http://www.pirx.com/gallery/albums/insect_festival/cave_spider.jpg&imgrefurl=http://www.pirx.com/gallery/insect_festival/cave_spider&h=494&w=759&sz=368&tbnid=1eKJtwURTRsVXM:&tbnh=103&tbnw=158&prev=/search%3Fq%3Dafrican%2Bcave%2Bspider%26tbm%3Disch%26tbo%3Du&zoom=1&q=african+cave+spider&docid=bg1o1qx2o6EIDM&hl=en&sa=X&ei=93RtTp74J6T10gHyzsXtBA&sqi=2&ved=0CCkQ9QEwAg&dur=1025

[Steven L.]

"r norman" <r_s_n...@comcast.net> wrote in message
news:iiiq6795kj2g0od05...@4ax.com:

> On Sun, 11 Sep 2011 14:57:13 -0700 (PDT), tapeh...@yahoo.com wrote:
>
> >This is a question from a creationist friend...
> >
> >If an animal's systems evolve only over a long period of time, without
> >any 'design', how did the animal survive, before all of the systems
> >were functional? Such as a giraffe's circulatory system? In short, why
> >didn't all giraffes die out before the little sponge-thingy in their
> >heads evolved, so as to soak up the gravity- fed blood flow before it
> >burst their brains?
>
> Others have already discussed this particular question -- that many
> extreme morphologies involve simultaneous changes to a number of
> physiological systems all of which can happen by a series of
> relatively small changes each of which can convey increases in
> fitness.
>
> But I happen to have recently returned from a visit to Africa where I
> had the opportunity to observe giraffes using their long necks and
> great height for feeding. There is a theory that says the feeding
> advantage is not at all sufficient -- why then are there not a lot of
> other herbivores that show comparable adaptations? Why is the giraffe
> unique? The answer was sexual selection because male giraffes use
> their long necks in ritualized combat to determine mating hierarchies.

Perhaps that's the same reason why a few sauropod species (e.g.
Brachiosaurs) evolved long necks that towered high in the sky, while
many other sauropod species (apatosaurs, diplodocus, etc.) did not?

It was sexual selection rather than browsing that caused some sauropods
to stick their necks out, so to speak?



-- Steven L.

[Steven L.]

"Darwin123" <drose...@yahoo.com> wrote in message
news:f8afa1df-2153-4fe7...@g9g2000yqb.googlegroups.com:

And I would make the point to this creationist friend that this
principle of gradual evolution of all the parts of a system doesn't just
apply to biological systems.

Cities evolve. Nations evolve. Societies evolve. Civilizations
evolve. In all cases, all the parts of the system evolve in tandem, so
the system continues to work at every step of the way.

What this creationist is asking about giraffes, would be equivalent to
asking how New York City managed to survive while its airports were
being constructed. The answer is that subway lines and bus lines and
roads were also being put into effect; so that once the airport opened
and later expanded, there were ways to get there and back.



-- Steven L.

[Ragnar]

"Steven L." <sdli...@earthlink.net> wrote in message
news:bsidnYZTP9lYnfPT...@earthlink.com...

>
>
> What this creationist is asking about giraffes, would be equivalent to
> asking how New York City managed to survive while its airports were being
> constructed. The answer is that subway lines and bus lines and roads were
> also being put into effect; so that once the airport opened and later
> expanded, there were ways to get there and back.
>

Not a good idea to use as an example something that is evidently designed.
R.

[rmj]

>
> But I happen to have recently returned from a visit to Africa where I
> had the opportunity to observe giraffes using their long necks and
> great height for feeding. There is a theory that says the feeding
> advantage is not at all sufficient -- why then are there not a lot of
> other herbivores that show comparable adaptations? Why is the giraffe
> unique? The answer was sexual selection because male giraffes use
> their long necks in ritualized combat to determine mating hierarchies.

That does not add up. If the predecessor of the giraffe had a normal
neck, why would sexual selection favor a long neck? Or why did a long
neck not become advantageous in sexual selection for many species?

[Chris Thompson]

"Ragnar" <rag...@NOSPAM.com> wrote in
news:0Yobq.2724$8D1....@newsfe19.ams2:

Heh. As a life-long NYC resident (except for a few years away at Uni) I
have to ask- do you really think anything in NYC was actually designed? Or
is it simply a cultural mutation? The airports are actually an excellent
example. Steven L. is incorrect on this- the airports are located far away
from any subway lines. Buses take torturous routes to JFK. LaGuardia isn't
so bad by bus from Manhattan, but only the most committed masochists fly
out of LaGuardia. For reasons not pertinent to this ng (check the archives
at nyc.transit) the air-train (light rail) that actually does go to JFK
forces one to go to a station in Jamaica (Queens, not the Caribbean,
although I would not have been surprised at the latter)far, far out of the
way for most people. And once you get to Jamaica Station, you cannot just
cross a platform to the Air Train; you have to walk (kids, luggage, pets,
whatnot trailing behind) to a _different_ station.

OK, maybe it was designed. But it was designed by an idiot.

Chris

[Mark Isaak]

Long necks on sauropods are energetically efficient because the saur can
browse a large area without needing to move its huge body.

[Paul J Gans]

The Bible doesn't mention any caves in Africa either, so there
can be no doubt that your hypothesis is right.

--
--- Paul J. Gans

[Mike Dworetsky]

Or, it was designed by someone who believed that only little people, who
didn't count, would try to use public transport to get to the airport.
Anyone worth considering like a pop star or company president would have a
limousine.

We used to have a situation vaguely similar in London about 35 years ago,
but one of the underground lines was extended to Heathrow Central, then as
Terminals 4 and 5 were built, this was extended to serve them as they were
opened. And about 20 years ago a new premium rail line was extended to
Heathrow nonstop. It's expensive, but it gets you there fast without
driving or parking.

At Gatwick Airport the railway station is built into the main terminal. If
you do need to change to other destinations it will usually be a matter of
get off and then board another train at the same platform, or change
services in central London.

Another airport with brilliant city to airport train service is Vienna. The
station is literally just at the terminal doors. And much cheaper than
London's Heathrow Express.

--
Mike Dworetsky

(Remove pants sp*mbl*ck to reply)

[tapeh...@yahoo.com]

Thank you for the response....That helps greatly.

[Bob Casanova]

On Mon, 12 Sep 2011 08:35:24 -0800, the following appeared
in talk.origins, posted by rmj <glennaRe...@jps.net>:

>>
>> But I happen to have recently returned from a visit to Africa where I
>> had the opportunity to observe giraffes using their long necks and
>> great height for feeding. There is a theory that says the feeding
>> advantage is not at all sufficient -- why then are there not a lot of
>> other herbivores that show comparable adaptations? Why is the giraffe
>> unique? The answer was sexual selection because male giraffes use
>> their long necks in ritualized combat to determine mating hierarchies.
>
>That does not add up. If the predecessor of the giraffe had a normal
>neck, why would sexual selection favor a long neck?

Sexual selection develops in parallel with morphological
changes.

>Or why did a long
>neck not become advantageous in sexual selection for many species?

Why do you not have a multicolored, elaborately patterned
spreadable fan of two-foot-long tailfeathers which all the
ladies can admire?
--

Bob C.

"Evidence confirming an observation is
evidence that the observation is wrong."
- McNameless

[r norman]

So why did/do so few browsers take advantage of that fact?

[Ron O]

On Sep 12, 5:30 pm, r norman <r_s_nor...@comcast.net> wrote:
> On Mon, 12 Sep 2011 09:05:09 -0700, Mark Isaak
>
>
>
>
>
>
>
>
>
> <eci...@curioustaxonomyNOSPAM.net> wrote:
> >On 9/12/11 5:44 AM, Steven L. wrote:
>

> >> "r norman" <r_s_nor...@comcast.net> wrote in message
> >>news:iiiq6795kj2g0od05...@4ax.com:

The long neck is going to slow you down among obstacles. You trade
maneuverability for energy efficiency. They seem to have gotten
around this by growing larger than the predators cared to deal with,
but this meant smaller populations with the available resources and
less variation and less ability to evolve around problems like disease
or cope with inbreeding depression.

Ron Okimoto

[Ron O]

On Sep 12, 11:05 am, Mark Isaak <eci...@curioustaxonomyNOSPAM.net>
wrote:

> On 9/12/11 5:44 AM, Steven L. wrote:
>
>
>
>
>
>
>
>
>
>
>

> > "r norman" <r_s_nor...@comcast.net> wrote in message
> >news:iiiq6795kj2g0od05...@4ax.com:

Think of the hose on your vacuum cleaner.

Ron Okimoto

[William Morse]

A good answer. I am skeptical of the sexual selection hypothesis, at
least as the sole explanation for the long neck of giraffes. Long necks
have evolved numerous times, and for aquatic creatures like elasmosaurs
and plesiosaurs, they would not have been effective in male combat. In
many bird species they are clearly just a feeding adaptation and not
subject to sexual selection. In the absence of information on at least
sexual dimorphism in long necked sauropods there is no reason to
speculate that their long necks were anything other than a feeding
adaptation.

Bill

[r norman]

The sexual selection hypothesis sounds somewhat unusual and Ron O's
argument and reasons seem completely sound and reasonable. The only
problem is that there is good evidence for the former but none for the
latter. That makes Ron's explanation a "just so story" -- a nice one
but still speculation.

The sexual selection hypothesis was presented in 1996 by Simmons and
Scheepers in The American Naturalist, a rather respected peer-reviewed
primary research journal, and is available at
http://www2.newpaltz.edu/~geherg/evos/simmons_scheepers.pdf

It is not the last story on the giraffe neck and I believe there
remains some controversy over the relative significance of feeding vs.
sexual selection in explaining the neck. However it is a valuable
lesson in showing that the "obviously true" just-so story might not be
so just after all.

[David Hare-Scott]

r norman wrote:
> On Mon, 12 Sep 2011 09:05:09 -0700, Mark Isaak
>>>>

>>> Perhaps that's the same reason why a few sauropod species (e.g.
>>> Brachiosaurs) evolved long necks that towered high in the sky, while
>>> many other sauropod species (apatosaurs, diplodocus, etc.) did not?
>>>
>>> It was sexual selection rather than browsing that caused some
>>> sauropods to stick their necks out, so to speak?
>>
>> Long necks on sauropods are energetically efficient because the saur
>> can browse a large area without needing to move its huge body.
>
> So why did/do so few browsers take advantage of that fact?

Domination of the market by the saurs at Microsoft?

D

[Dakota]

My question is:

If your 'diligent' searches for caves in Africa did not include taking a
peek as some of the 32 million hits from the Google search on "african
caves," why should anyone believe your unreferenced gossip?

[rmj]

On 9/12/2011 1:31 PM, Bob Casanova wrote:
> On Mon, 12 Sep 2011 08:35:24 -0800, the following appeared
> in talk.origins, posted by rmj<glennaRe...@jps.net>:
>
>>>
>>> But I happen to have recently returned from a visit to Africa where I
>>> had the opportunity to observe giraffes using their long necks and
>>> great height for feeding. There is a theory that says the feeding
>>> advantage is not at all sufficient -- why then are there not a lot of
>>> other herbivores that show comparable adaptations? Why is the giraffe
>>> unique? The answer was sexual selection because male giraffes use
>>> their long necks in ritualized combat to determine mating hierarchies.
>>
>> That does not add up. If the predecessor of the giraffe had a normal
>> neck, why would sexual selection favor a long neck?
>
> Sexual selection develops in parallel with morphological
> changes.

That is no explanation.

>
>> Or why did a long
>> neck not become advantageous in sexual selection for many species?
>
> Why do you not have a multicolored, elaborately patterned
> spreadable fan of two-foot-long tailfeathers which all the
> ladies can admire?

There are a number of bird species with impressive tail feathers.
The question was why and your answer is why not. Just admit scientists
don't know and accept that regarding sexual selection as cause for an
elongated neck is speculation.

[r norman]

On Mon, 12 Sep 2011 22:57:01 -0500, Dakota <ma...@NOSPAMmail.com>

I am not asking anyone to believe my observations. I merely present
them. As I already said, you are free to believe whatever you want.

The question of whether there are caves in Africa has a long history
here on t.o. The hypothesis that there are none is not my own -- in
fact it is one I set out to disprove by my own observations. As an
honest observer I felt compelled to report that I was unable to do so.

[Dakota]

You inability to do so suggests a egregious lack of diligence. Did you
make your observations before the internet became available? In modern
times, diligence requires using modern references. Did you diligence
involve inquiring of travel agents or government agencies? Did you speak
with natives of the areas you visited about local caves?

The hypothesis that there is no cave in Africa may have a long history
on T.O. but it must have been very sporadic indeed to have escaped my
attention.

[r norman]

On Tue, 13 Sep 2011 08:08:18 -0500, Dakota <ma...@NOSPAMmail.com>

I should have said "old history" rather than "long history".

I claim only to report what I personally observed. I cannot attest to
the reliability of what other people may say. That includes web
searches which frequently turn up outlandish and utterly false
reports. Do a web search for "truth in the Bible" and inquire about
that topic at all your local evangelical fundamentalist churches. A
diligent search on that topic by your standards would be very
interesting.

You suggest a lack of due diligence on my part. I notice that you do
not refute any statement I have made.

[Dakota]

Searches for 'truth in the Bible' cannot be reasonably compared with
searches for the geological feature of a nation. The various Bibles are
open to interpretation but the fact of a cave's existence can be
factually demonstrated. A better comparison might be a search for
'rivers in Asia.'

I have refuted your claim that you have diligently searched for caves.
You ignored my questions into the methods that justify your claim of due
diligence. I've repeated them below. Please answer them.

Did you make your observations before the internet became available? In

modern times, diligence requires using modern references. Did your

[r norman]

On Tue, 13 Sep 2011 08:49:23 -0500, Dakota <ma...@NOSPAMmail.com>

I accurately reported exactly what I did. While in Africa I
diligently looked around me to see if I could observe from my own
personal experience any caves. Who are you to dictate whether or not
I diligently looked both left and right, up and down, in all
directions? I did diligently inspect my environment and I did not
discover any cave. Nor did any person I met describe any caves in the
vicinity that I could inspect. I then reported correctly and
accurately my results: from my own direct knowledge, I cannot
disprove by example the hypothesis that there are no caves in Africa.

Nothing you ask about bears on my statement. I presented my
experimental methods (direct personal observation), my results (a
failure to observe a cave), and my conclusion (that I cannot refute
the hypothesis in question). You show me the error in what I did.
Perhaps you may have wished me to conduct my research in a different
way. That can be said about every published scientific paper. I did
what I did and I reported it correctly and accurately and drew proper
and correct logical conclusions from my work. You say my work is
incomplete. Again, that is true about all science -- there is always
more to be done. Perhaps the next time I visit Africa I will use a
different approach to investigate that hypothesis.

[Bob Casanova]

On Mon, 12 Sep 2011 23:52:14 -0800, the following appeared

in talk.origins, posted by rmj <glennaRe...@jps.net>:

>On 9/12/2011 1:31 PM, Bob Casanova wrote:
>> On Mon, 12 Sep 2011 08:35:24 -0800, the following appeared
>> in talk.origins, posted by rmj<glennaRe...@jps.net>:
>>
>>>>
>>>> But I happen to have recently returned from a visit to Africa where I
>>>> had the opportunity to observe giraffes using their long necks and
>>>> great height for feeding. There is a theory that says the feeding
>>>> advantage is not at all sufficient -- why then are there not a lot of
>>>> other herbivores that show comparable adaptations? Why is the giraffe
>>>> unique? The answer was sexual selection because male giraffes use
>>>> their long necks in ritualized combat to determine mating hierarchies.
>>>
>>> That does not add up. If the predecessor of the giraffe had a normal
>>> neck, why would sexual selection favor a long neck?
>>
>> Sexual selection develops in parallel with morphological
>> changes.
>
>That is no explanation.

For you, probably not. For those who understand how
evolution works it is. But try this: If the necks of
giraffes are selected for length as a response to feeding
opportunities, and the increased neck length turns out to be
useful in mating battles, it's a double whammy in their
favor. That's what the above comment meant.

>>> Or why did a long
>>> neck not become advantageous in sexual selection for many species?
>>
>> Why do you not have a multicolored, elaborately patterned
>> spreadable fan of two-foot-long tailfeathers which all the
>> ladies can admire?
>
>There are a number of bird species with impressive tail feathers.
>The question was why and your answer is why not. Just admit scientists
>don't know and accept that regarding sexual selection as cause for an
>elongated neck is speculation.

Nope. Giraffes actually use those long necks in mating
battles, so the connection between longer and stronger necks
and sexual selection is pretty clear.

[chris thompson]

On Sep 12, 12:22 pm, "Mike Dworetsky"

<platinum...@pants.btinternet.com> wrote:
> Chris Thompson wrote:
> > "Ragnar" <rag...@NOSPAM.com> wrote in
> >news:0Yobq.2724$8D1....@newsfe19.ams2:
>

> >> "Steven L." <sdlit...@earthlink.net> wrote in message

Sounds like heaven- and I live about a 15 minute drive from JFK.

Chris

[Ron O]

I didn't say that the explanation applied to giraffes. They are built
differently than sauropods. The neck is an upright structure in
giraffes where the sauropods likely spent a lot of time with their
necks horizontal to the ground using their necks as vacuum cleaner
hoses. They have their tails to compensate for the horizontal
extension. Giraffes have to get into awkward positions to lower their
heads. Their balance point is not with their heads away from their
body mass. They basically screwed themselves with their long neck and
limited their access to the food supply. They will browse on bushes,
but they aren't very graceful about it. The feeders at the zoo are
not at ground level.

Ron Okimoto

[Paul J Gans]

It is heaven. Each time I've been to London I've taken the
underground line from Heathrow. In the outskirts it runs on
the ground, not under it.

There was an odd feeling. London underground rail cars are not
that different than New York ones (except for the perpetual
"mind the gap" announcements every time the doors opened).
But gazing out the window at the unfolding landscape was
amazing. One was clearly NOT in New York or even out on
the Long Island Rail Road. The first time was a wonderful
introduction to England.

[r norman]

On Tue, 13 Sep 2011 16:36:49 -0700 (PDT), Ron O <roki...@cox.net>
wrote:

Thanks for the clarification. You are right, your argument is far
better for the sauropods than for the giraffe. However giraffes have
no problem holding their heads at a horizontal level without balance
issues. They regularly browse at low levels even when food is
available higher.

How awkward and stable the sauropods were, of course, is rather
speculative. There have been significant changes in our thinking
about postures and locomotion of many of the dinosaurs over time.

[David Hare-Scott]

I was watching a documentary on Windsor Castle. One of the American
tourists was interviewed and declared that it was just wonderful, everything
that they had wanted to see in a real English castle but it was such a shame
that they built it so near the airport.

D

[William Morse]

I agree with your statement about the "obviously true" just-so story,
and I was already familiar with the sexual selection hypothesis. But on
rereading the American Naturalist article (thanks for providing the
reference), Simmons and Scheepers make a number of assumptions in
support of their hypothesis that are not entirely supported by the
evidence, and also fail to address the obvious counter-question to yours
above: if long necks are a result of sexual selection why did/do so few
ungulates exhibit them? We have all sorts of varieties of horns, but we
only have one variety of long neck. Elephant seals, which exhibit a
somewhat similar form of male combat to "necking", have very thick necks
but not very long necks.

The allometric argument of Simmons and Scheepers fails in the face of
numerous examples of other species who have opted for long necks as a
feeding adaptation rather than allometric scaling. They cite the switch
in dry season feeding from high Acacia to low Grewia, but even though
they noted the low protein content of Acacia in the dry season, they did
not make the connection that the switch might be due to Grewia being a
preferable food source during the dry season

(See www.lifesciencesite.com/lsj/life0802s/13_6242life0802s_81_90.pdf)

The authors acknowledge that "selective forces giving rise to
morphological traits may not be the same as those maintaining them". In
this case I think it is more the case that an initial feeding trait was
then coopted by sexual selection. The authors note that giraffes do not
exhibit typical ungulate fighting patterns, but this argument is not
germane - given their long necks they couldn't fight that way. In fact
this argument reinforces the idea that the long necks initially evolved
as a feeding mechanism, since otherwise presumably the giraffes would
have just kept fighting the old fashioned way.

So I will have to disagree with you about the evidence. The authors
presented some good evidence for sexual selection, but there is also
plenty of good evidence for feeding adaptation. I think Orgel will turn
out to have the last word on this one :-)

Bill

[Earle Jones]

In article <2rfu67t049f34uk9n...@4ax.com>,

*
For a listing of African caves, take a look at:

http://en.wikipedia.org/wiki/List_of_caves#Algeria

This is a fairly comprehensive list of the hundreds of African caves by
country.

Where the idea that there are no caves in Africa came from, I can't
recall. But it was bandied around by some posters here about ten years
(?) ago.

earle
*

[rmj]

On 9/13/2011 1:41 PM, Bob Casanova wrote:
> On Mon, 12 Sep 2011 23:52:14 -0800, the following appeared
> in talk.origins, posted by rmj<glennaRe...@jps.net>:
>
>> On 9/12/2011 1:31 PM, Bob Casanova wrote:
>>> On Mon, 12 Sep 2011 08:35:24 -0800, the following appeared
>>> in talk.origins, posted by rmj<glennaRe...@jps.net>:
>>>
>>>>>
>>>>> But I happen to have recently returned from a visit to Africa where I
>>>>> had the opportunity to observe giraffes using their long necks and
>>>>> great height for feeding. There is a theory that says the feeding
>>>>> advantage is not at all sufficient -- why then are there not a lot of
>>>>> other herbivores that show comparable adaptations? Why is the giraffe
>>>>> unique? The answer was sexual selection because male giraffes use
>>>>> their long necks in ritualized combat to determine mating hierarchies.
>>>>
>>>> That does not add up. If the predecessor of the giraffe had a normal
>>>> neck, why would sexual selection favor a long neck?
>>>
>>> Sexual selection develops in parallel with morphological
>>> changes.
>>
>> That is no explanation.
>
> For you, probably not. For those who understand how
> evolution works it is. But try this: If the necks of
> giraffes are selected for length as a response to feeding
> opportunities, and the increased neck length turns out to be
> useful in mating battles, it's a double whammy in their
> favor. That's what the above comment meant.

Good, you are allowing for a more complex answer. A long neck is useful
for feeding, it is desirable in winning a mate, and one can also add it
is likely useful for seeing predators approaching. Too often the
approach is to name a single reason.

>
>>>> Or why did a long
>>>> neck not become advantageous in sexual selection for many species?
>>>
>>> Why do you not have a multicolored, elaborately patterned
>>> spreadable fan of two-foot-long tailfeathers which all the
>>> ladies can admire?
>>
>> There are a number of bird species with impressive tail feathers.
>> The question was why and your answer is why not. Just admit scientists
>> don't know and accept that regarding sexual selection as cause for an
>> elongated neck is speculation.
>
> Nope. Giraffes actually use those long necks in mating
> battles, so the connection between longer and stronger necks
> and sexual selection is pretty clear.

That avoids the argument. If the giraffe's predecessor had a normal size
neck, then there is no reason to think that an individual with a neck
one inch longer would be more attractive to the female. More likely
females would be less attracted to this "deformed" male.

[Mike Dworetsky]

It's those bastard Norman property developers. They'll get you every time.

[VoiceOfReason]

IIRC, one of the evo-denialists (can't remember which one...
[M]adhat?) tried refuting the idea of early homo fossils in caves in
southern Africa by claiming that there are no caves in Africa.

Yeah... he was a laughing stock for a while.

[r norman]

I do not deny that people claim there to be caves in Africa. That is
why I wanted to see for myself whether it was true. I went to Africa
and did not see any so, from this evidence, the claim cannot be
corroborated.

The argument that there are no caves in Africa was not merely bandied
about -- it was voted the best post of its kind back in May 2003.

[Ernest Major]

In message
<901da7ed-b8c7-4a89...@hb5g2000vbb.googlegroups.com>,
VoiceOfReason <papa...@cybertown.com> writes

>
>
>Earle Jones wrote:
>> In article <2rfu67t049f34uk9n...@4ax.com>,
>> r norman <r_s_n...@comcast.net> wrote:
>>
>> > On Mon, 12 Sep 2011 22:57:01 -0500, Dakota <ma...@NOSPAMmail.com>
>> > wrote:
>> >
>> > >On 9/11/2011 9:06 PM, r norman wrote:
>> > >> On Sun, 11 Sep 2011 20:19:51 -0500, Dakota<ma...@NOSPAMmail.com>
>> > >> wrote:
>> > >>
>> > >>> On 9/11/2011 7:06 PM, r norman wrote:
>> > >>>> On Sun, 11 Sep 2011 14:57:13 -0700 (PDT), tapeh...@yahoo.com wrote:
>> > >>>>
>> > >>>>> This is a question from a creationist friend...
>> > >>>>>
>> > >>>>> If an animal's systems evolve only over a long period of

Nowhere Man

>tried refuting the idea of early homo fossils in caves in
>southern Africa by claiming that there are no caves in Africa.

As I recall, his words were "Where are there caves in Africa?" (Google
Groups elaborates them as "Caves? I thought this was in Africa. Where
are there caves in Africa?".)

He did backpedal downthread, but no-one seems to have believed the
backpedal.

>
>Yeah... he was a laughing stock for a while.
>

It is an archetypical Chez Watt, in the stunningly ignorant category.
--
alias Ernest Major

[Richard Harter]

On Tue, 13 Sep 2011 10:14:42 -0400, r norman <r_s_n...@comcast.net>

I'm very proud of you. Well done, sir.

[VoiceOfReason]

Ah ok -- thanks for the correction.

[Boozer]

On Sep 11, 4:57 pm, tapehead...@yahoo.com wrote:
> This is a question from a creationist friend...
>

> If an animal's systems evolve only over a long period of time, without

> any 'design', how did the animal survive, before all of the systems
> were functional? Such as a giraffe's circulatory system? In short, why
> didn't all giraffes die out before the little sponge-thingy in their
> heads evolved, so as to soak up the gravity- fed blood flow before it
> burst their brains?

Most did, whole heards of long necked bursted brains pseudo-giraffes
were probably laying around the african plains dead..they went extinct
trying to get a drink of water.. the few heards of long necked
pseudo-giraffes who developed spongy-LIKE-thingies had more kids that
had better spongy-LIKE-thingies who had more kids that had better
spongy-like-thingies..extrapolate to real spongy-thingies in current
day giraffes.

[Richard Harter]

On Tue, 13 Sep 2011 16:36:49 -0700 (PDT), Ron O <roki...@cox.net>
wrote:

>I didn't say that the explanation applied to giraffes. They are built
>differently than sauropods. The neck is an upright structure in
>giraffes where the sauropods likely spent a lot of time with their
>necks horizontal to the ground using their necks as vacuum cleaner
>hoses. They have their tails to compensate for the horizontal
>extension. Giraffes have to get into awkward positions to lower their
>heads. Their balance point is not with their heads away from their
>body mass. They basically screwed themselves with their long neck and
>limited their access to the food supply. They will browse on bushes,
>but they aren't very graceful about it. The feeders at the zoo are
>not at ground level.

OTOH the brachiosaurs were built like giraffes. They may well have
had the same issues as giragges - on a larger scals of course.


>

[r norman]

On Wed, 14 Sep 2011 06:28:56 -0700 (PDT), Boozer <oleb...@yahoo.com>
wrote:

I never herd of such a thing.

[Glenn]

"r norman" <r_s_n...@comcast.net> wrote in message
news:oth177dnpgmapjpck...@4ax.com...

Jest extrapolate.

[Bob Casanova]

On Tue, 13 Sep 2011 22:37:49 -0800, the following appeared

I'm simply explaining what the statement I made meant, since
you didn't understand it. That doesn't make it more complex,
it makes it simpler, albeit using more words.

> A long neck is useful
>for feeding, it is desirable in winning a mate, and one can also add it
>is likely useful for seeing predators approaching. Too often the
>approach is to name a single reason.
>
>>
>>>>> Or why did a long
>>>>> neck not become advantageous in sexual selection for many species?
>>>>
>>>> Why do you not have a multicolored, elaborately patterned
>>>> spreadable fan of two-foot-long tailfeathers which all the
>>>> ladies can admire?
>>>
>>> There are a number of bird species with impressive tail feathers.
>>> The question was why and your answer is why not. Just admit scientists
>>> don't know and accept that regarding sexual selection as cause for an
>>> elongated neck is speculation.
>>
>> Nope. Giraffes actually use those long necks in mating
>> battles, so the connection between longer and stronger necks
>> and sexual selection is pretty clear.
>
>That avoids the argument.

No, it doesn't.

> If the giraffe's predecessor had a normal size
>neck, then there is no reason to think that an individual with a neck
>one inch longer would be more attractive to the female. More likely
>females would be less attracted to this "deformed" male.

John Holmes would probably disagree. And I'm finished with
this.

[Ron O]

On Sep 13, 7:08 pm, r norman <r_s_nor...@comcast.net> wrote:
> On Tue, 13 Sep 2011 16:36:49 -0700 (PDT), Ron O <rokim...@cox.net>

When I've seen giraffes go horizontal, graceful is not a word I would
use to describe it. They have to set their legs forward and sway back
like they are going to sit down. This is not a position that you
would want to be in to avoid predators, and has to be a muscle strain
on the legs. Sauropods could stand normally and sweep an area by just
moving their heads and tails, and probably shifting their body weight
a little.

Ron Okimoto

[r norman]

On Thu, 15 Sep 2011 04:41:57 -0700 (PDT), Ron O <roki...@cox.net>
wrote:

>On Sep 13, 7:08 pm, r norman <r_s_nor...@comcast.net> wrote:
>> On Tue, 13 Sep 2011 16:36:49 -0700 (PDT), Ron O <rokim...@cox.net>
>> wrote:
>>

<snip to retain giraffe posture only>

I have photographs of giraffes browsing with their necks held
horizontally. Their legs are held quite normally. I have a photo
showing two giraffes side by side. One is browsing highl with the
neck held "normally", the other with the neck horizontal. Both seem
to have quite identical stances otherwise with legs straight vertical.
When I watched the giraffes feed they moved seeming effortlessly from
browsing hig to browsing at shoulder level with horizontal necks with
no apparent change in leg position or posture.

Feeding is not a position you want to be in to avoid predators. That
is why virtually all animals who sense danger stop feeding. I also am
not sure about how you collect data on sauropod neck sweeps. I
thought the current thinking about sauropods is that they normally
held their necks elevated, just like giraffes although they were
capable of swinging them to horizontal or ground levels, just like
giraffes.

[Glenn]

"Ron O" <roki...@cox.net> wrote in message
news:51952ca2-ad04-4061...@l2g2000vbn.googlegroups.com...

Here's a giraffe trying to get up after sleeping

http://www.youtube.com/watch?v=fnK75Zp3P7c

I don't have one of a sauropod.

[r norman]

On Tue, 13 Sep 2011 16:36:49 -0700 (PDT), Ron O <roki...@cox.net>
wrote:

In support of your argument about sauropods, Taylor et al have a new
paper in J Zool pretty well destroying the notion that sauropod necks
resulted from sexual selection.
The long necks of sauropods did not evolve primarily
through sexual selection
M. P. Taylor, D. W. E. Hone, M. J. Wedel & D. Naish
(online version available before print for J. Zool, 2011)
doi:10.1111/j.1469-7998.2011.00824.x

Full text available at

http://www.miketaylor.org.uk/dino/pubs/taylor-et-al-2011b/TaylorEtAl2011-sauropod-necks-not-sexually-selected.pdf

[Ron O]

On Sep 15, 7:06 am, r norman <r_s_nor...@comcast.net> wrote:
> On Thu, 15 Sep 2011 04:41:57 -0700 (PDT), Ron O <rokim...@cox.net>

This isn't what I recall, but my experience was only with a giraffe
bending over that people were feeding. It was a docile giraffe and
could have been old and feeble for all I know, but the keepers were
letting kids feed the animal carrots. I may be mixing up memories,
but the fence was absurdly low (only around waist height and the kids
could offer the carrots above the fence to the animal. The enclosure
didn't have the regular ditch around it, but only had a step down of
around 2 feet. The giraffe would not take that step. It could have
probably easily walked over the fence if it would have been willing to
take that step down. So it's head was likely coming pretty close to
it's ground level to get the treats. There was a definite tilt
backwards angle to the legs.

http://www.tripadvisor.com/LocationPhotos-g293766-Botswana.html

It was not as exaggerated as this stance, but it was something like
it.

Ron Okimoto

[r norman]

On Fri, 16 Sep 2011 04:14:46 -0700 (PDT), Ron O <roki...@cox.net>
wrote:

The awkward pictures all seem to include giraffes with their heads at
ground level, not feeding horizontally pretty much at shoulder height.
Incidentally, they were taken from the same location I visited --
Chobe National Park.

[Nick Keighley]

On Sep 14, 1:35 am, "David Hare-Scott" <sec...@nospam.com> wrote:
> Paul J Gans wrote:

> > chris thompson <chris.linthomp...@gmail.com> wrote:

<public transport toairports>

> >> Sounds like heaven- and I live about a 15 minute drive from JFK.

I can walk 10minutes to the centre of my town and catch a direct bus
to my nearest London airport. The people who live near it moan about
the noise and planned expansions but I get the best of both worlds!

> > It is heaven.  Each time I've been to London I've taken the
> > underground line from Heathrow.  In the outskirts it runs on
> > the ground, not under it.
>
> > There was an odd feeling.  London underground rail cars are not
> > that different than New York ones (except for the perpetual
> > "mind the gap" announcements every time the doors opened).
> > But gazing out the window at the unfolding landscape was
> > amazing.  One was clearly NOT in New York or even out on
> > the Long Island Rail Road.  The first time was a wonderful
> > introduction to England.

amazing to here something that surprises and delights a non-native

> I was watching a documentary on Windsor Castle.  One of the American
> tourists was interviewed and declared that it was just wonderful, everything
> that they had wanted to see in a real English castle but it was such a shame
> that they built it so near the airport.

LOL!

[VoiceOfReason]

On Sep 16, 9:12 am, Nick Keighley <nick_keighley_nos...@hotmail.com>
wrote:

That's one of those moments you might be tempted to say, "Me?
American? Er, no, I'm Canadian actually..." *cough*

[r norman]

On Fri, 16 Sep 2011 04:14:46 -0700 (PDT), Ron O <roki...@cox.net>
wrote:

Having examined a number of photos of giraffes I think I can resolve
this issue. Of course I am speculating; I would have to return to
Africa to investigate further. I would love to do so but there are a
few problems -- actually many thousands of problems in doing so.

The problem is that I was concentrating on your initial suggestion of
a problem in balance in lowering the head. I think it merely a
problem of mechanical advantage of the neck and shoulder muscles. The
giraffe can easily lower its neck to a horizontal (or near horizontal)
position without effort according to my observations. It is lowering
the neck to a lower position -- below horizontal which, of course,
includes down to the ground as the extreme case. The muscles seem not
to be located to be able to pull the head up once the neck is below
horizontal. For an analogy, think of your biceps muscle as flexing
your arm. If you extend your arm all the way (to a 180 degree angle)
then the biceps has a very unfavorable mechanical advantage in trying
to flex but it will still work a bit. If you were able to hyperextend
your elbow beyond 180 degrees, the biceps would fail completely -- it
would pull in the wrong direction. I think that is the problem of the
giraffe -- it can lower the neck only so far and still be able to
raise it. So, to solve the problem of feeding or drinking at lower
levels, it simply lowers its entire body, tilting the back by lowering
the front legs and raising the rear ones. Most animals simply flex
their front legs and extend their rear ones to tilt the back
downwards. The giraffe instead splays the front legs to lower the
front of the body. There is no problem in balance -- only in muscle
mechanics.

The sauropods must have very similar problems. Sauropods had a lot
more vertebrae in their necks and so could probably curve their necks
far better than giraffes. That way they could have the base of the
neck remain above horizontal and still curve their head down to the
ground.

But again, this is all speculation. I don't know the actual mechanics
involved.

[Steven L.]

"Mark Isaak" <eci...@curioustaxonomyNOSPAM.net> wrote in message
news:j4laji$fo1$1...@speranza.aioe.org:

> On 9/12/11 5:44 AM, Steven L. wrote:
> >
> >

> > "r norman" <r_s_n...@comcast.net> wrote in message

That wasn't my point.

The Brachiosaurs elevated their necks high into the sky, like giraffes.

But many other species of sauropod kept their necks and heads close to
the ground, like the Diplodocus.

So perhaps the same reason that the giraffe's head is high, is the same
reason that the Brachiosaur's head was high: Sexual selection.





-- Steven L.

[Steven L.]

"Bob Casanova" <nos...@buzz.off> wrote in message
news:s7jv679tm0crqs4kj...@4ax.com:

> On Mon, 12 Sep 2011 23:52:14 -0800, the following appeared
> in talk.origins, posted by rmj <glennaRe...@jps.net>:
>

> >On 9/12/2011 1:31 PM, Bob Casanova wrote:
> >> On Mon, 12 Sep 2011 08:35:24 -0800, the following appeared
> >> in talk.origins, posted by rmj<glennaRe...@jps.net>:
> >>
> >>>>

> >>>> But I happen to have recently returned from a visit to Africa where I
> >>>> had the opportunity to observe giraffes using their long necks and
> >>>> great height for feeding. There is a theory that says the feeding
> >>>> advantage is not at all sufficient -- why then are there not a lot of
> >>>> other herbivores that show comparable adaptations? Why is the giraffe
> >>>> unique? The answer was sexual selection because male giraffes use
> >>>> their long necks in ritualized combat to determine mating hierarchies.
> >>>

> >>> That does not add up. If the predecessor of the giraffe had a normal
> >>> neck, why would sexual selection favor a long neck?
> >>
> >> Sexual selection develops in parallel with morphological
> >> changes.
> >
> >That is no explanation.
>
> For you, probably not. For those who understand how
> evolution works it is. But try this: If the necks of
> giraffes are selected for length as a response to feeding
> opportunities, and the increased neck length turns out to be
> useful in mating battles, it's a double whammy in their
> favor. That's what the above comment meant.
>

> >>> Or why did a long
> >>> neck not become advantageous in sexual selection for many species?
> >>
> >> Why do you not have a multicolored, elaborately patterned
> >> spreadable fan of two-foot-long tailfeathers which all the
> >> ladies can admire?
> >
> >There are a number of bird species with impressive tail feathers.
> >The question was why and your answer is why not. Just admit scientists
> >don't know and accept that regarding sexual selection as cause for an
> >elongated neck is speculation.
>
> Nope. Giraffes actually use those long necks in mating
> battles, so the connection between longer and stronger necks
> and sexual selection is pretty clear.

And that's fine, because we can actually watch these mating battles.

But inferring sexual selection from fossils of long-extinct creatures
seems to be much more speculative. And unfalsifiable:

"The creature was bigger [or stronger or faster], an advantage which
also made it more attractive to the opposite sex."
"The creature had a trait for which we can find no advantage, so it must
have been sexual selection."

It seems like you can postulate sexual selection for any trait for which
the evolutionary advantage is otherwise unclear. It's a kind of
all-purpose fallback "explanation."

-- Steven L.

[Richard Harter]

Or, as I often do, just tell them that I'm from Baja Canada. In my
experience a surprising number of Europeans are almost as vague about
North American geography as Americans are.

[Mike Lyle]

On Fri, 16 Sep 2011 07:30:52 -0700 (PDT), VoiceOfReason
<papa...@cybertown.com> wrote:

Son, b-i-l, and I were once lucky enough to see Barcelona play at
home; behind us was a modestly rowdy but amiable English-speaking
inebriate. We asked him where he was from, and he said he was a Kiwi,
but usually pretended to be an Aussie when drunk. Clearly not a good
liar.

--
Mike.

[Bob Casanova]

On Fri, 16 Sep 2011 18:49:55 +0000, the following appeared
in talk.origins, posted by "Steven L."
<sdli...@earthlink.net>:

I'd say rather that it can be inferred in extinct species
from what we observe in current species which are close
relatives; it's unlikely that it's a recent phenomenon. That
said, I'd like some examples of claimed sexual selection in
species known only from fossils, especially those for which
there are no current close analogs (such as apatosaurus).

And of course, someone who isn't a layman may well be able
to give a better answer.

[Steven L.]

"Bob Casanova" <nos...@buzz.off> wrote in message

news:1cd977t7mtpcmqj74...@4ax.com:

All those head crests on some Cretaceous dinosaurs like Parasaurolophus,
for example. Or the crests of pterosaurs even further back in time.
Since paleontologists have never come to a consensus as to what those
crests were for, they seem to have reverted to speculating that they
were sexual lures.

Yes, there are species today whose head crests attract a mate. But
that's a pretty weak argument to claim that's what crests are always
for, even 66 million years ago.

"What else could it have been?" is always a bad argument in science.

> And of course, someone who isn't a layman may well be able
> to give a better answer.

Not so far.




-- Steven L.

[r norman]

"What else" is not always a bad argument. If there is no alternative
known and the notion is not patently ridiculous but indeed has some
merit then it stands as "the best explanation we have". Best to date,
that is. All explanations in science are subject to revision as new
information and new ideas arise.

Concluding "it could not be otherwise", on the other hand, is a bad
argument but that is quite a different story.

I already cited a paper that argues that sexual selection was not the
mechanism leading to the long necks of sauropods. We can infer things
about extinct species from combining fossil records with what we know
of extant organisms.

[Bob Casanova]

On Tue, 20 Sep 2011 15:24:17 +0000, the following appeared

OK. So? Speculation is valid in science as long as it's not
presented as fact or testable hypothesis. Did any scientist
so present it?

>Yes, there are species today whose head crests attract a mate. But
>that's a pretty weak argument to claim that's what crests are always
>for, even 66 million years ago.
>
>"What else could it have been?" is always a bad argument in science.

Yes, it is. Where did you see this argument made by a
scientist?

>> And of course, someone who isn't a layman may well be able
>> to give a better answer.

>Not so far.
--

[Bob Casanova]

On Tue, 20 Sep 2011 11:51:04 -0400, the following appeared
in talk.origins, posted by r norman
<r_s_n...@comcast.net>:

Thanks for joining. I suspect the subtle difference may
elude some.

>I already cited a paper that argues that sexual selection was not the
>mechanism leading to the long necks of sauropods. We can infer things
>about extinct species from combining fossil records with what we know
>of extant organisms.

That was my initial argument (inference from the known).