Grumpy

I'm going to go out on a limb here (ha!) and suggest another way to think about it -- just for the exercise. Let's say the motivating force for the loss of ape tails was sexual selection. Somebody gets it in their head that long tails are ugly, and proceeds to mate with partners with the smallest tails. Quicker than you can say anti-peacock, ape tails shrink down to invisible nubs. Of course, this requires compound mutations: tail size on the one hand, tail-rejection behavior on the other. But crazier things have been proposed.

I'm just trying to get away from the assumption that having or lacking a tail makes a functional difference in the lifestyle of an ape. It may, but it may also be that tails could just as easily have remained, all other things being equal.

This concept may have limited applicability in the case of skunk spray, however.

KeithHarwood

Of course faster animals are being selected for at the same time. We have pre-skunks. Some are faster than others, they have more offspring and their offspring are faster. We have stinky pre-skunks, some are stinkier than others, they have more offspring and their offspring are also stinkier. We have climbing pre-skunks, some climb faster than others and have more offspring. Eventually all the pre-skunks that are neither fast nor stinky nor climbers have been eaten and we end up with non-skunks that are a bit stinky, fair climbers and very fast, we have non-skunks which are a bit stinky, fairly fast and very good climbers and we have skunks which are fairly fast, fair climbers and very stinky.

There you have it. Three separate species. If you follow only one lineage you are missing two thirds of the story. If all you look at is how skunks evolved from pre-skunks you miss out on all the other things that evolved from pre-skunks. No doubt someone round here can identify the two non-skunk species, and probably the species that had yet other strategies of survival.

BTW, someone asked a biologist what was the name of an animal that neither fights nor runs away. He said the technical term for such an animal is `lunch'.

[ June 13, 2002: Message edited by: KeithHarwood ]</p>

lpetrich

Because it has only limited usefulness if one lives on the ground.

Duvenoy

The major preditor of skunks, aside from automobiles, is the great horned owl, who has no sense of smell.

Just thought I'd toss that in. Nobody's ride is free.

doov

Stephen T-B

<a href="http://iidb.org/ubb/icons/icon12.gif" target="_blank">http://iidb.org/ubb/icons/icon12.gif</a>
KeithHarwood wrote: "Of course faster animals are being selected for at the same time. We have pre-skunks. Some are faster than others, they have more offspring and their offspring are faster. We have stinky pre-skunks, some are stinkier than others, they have more offspring and their offspring are also stinkier. We have climbing pre-skunks, some climb faster than others and have more offspring. Eventually all the pre-skunks that are neither fast nor stinky nor climbers have been eaten and we end up with non-skunks that are a bit stinky, fair climbers and very fast, we have non-skunks which are a bit stinky, fairly fast and very good climbers and we have skunks which are fairly fast, fair climbers and very stinky.

There you have it Three separate species.If you follow only one lineage you are missing two thirds of the story. If all you look at is how skunks evolved from pre-skunks you miss out on all the other things that evolved from pre-skunks. No doubt someone round here can identify the two non-skunk species, and probably the species that had yet other strategies of survival.

BTW, someone asked a biologist what was the name of an animal that neither fights nor runs away. He said the technical term for such an animal is `lunch'."

I'm taking up this space because I like that so much I just wanted to see it again. And Douglas J.Bender to see it again.
Also it contains a clue about sensible deduction: if you see something very remarkable, very astonishing and apparently completely inexplicable, do you assume magic's involved somewhere? Or do you assume something's going on which has a rational explanation but which you haven't grasped because you are not in possession of all the facts?
The really good thing about Knowledge is that it obliterates superstition.

Douglas J. Bender

Strange. I wonder why all the merely "stinky" pre-skunks weren't all gobbled up by the "great horned owls". Or did the pre-"great horned owls" develop a lack of sense of smell in response to the stench of their favorite meals, slow and non-climbing, but stinky, pre-skunks?


In Christ,

Douglas

Oolon Colluphid

Bwahaha! Douglas doesn’t even know the standard creationist argument! The claim is that the muscles attach to it aid in defecation. I imagine these muscles are well developed in creationists, the better to argue with.

Oh deary-dear. Douglas, since when does ‘vestigial’ have to mean ‘totally lacking in function’? To repeat what I posted <a href="http://iidb.org/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=58&t=000889&p=" target="_blank">here (10 June)</a>, to save Douglas having to follow a link:

The key is that these features are morphologically very similar to more substantial versions in (for many other reasons, apparently related) creatures.

Plenty of bones begin as they end, as single pieces, if that’s what’s needed. To perform its function as a muscle attachment point, the coccyx does not need to start as separate pieces of bones that then fuse. A single protruberance from the pelvis could do that job. These pieces of bone, moreover, are in precisely the same place and are precisely the sort of shape as the bones which form the tail in mammals that have one. Having a tail is the default setting for mammals, remember.

Guinea pigs, for instance, have a coccyx a bit larger than ours, but it still doesn’t protrude beyond the skin. When a coccyx is bigger, and does protrude beyond the rump, we call that sort of coccyx a ‘tail’.

The mandrill baboon has a much smaller tail than other baboons:



Yet it is still clearly a tail, just greatly reduced. What might these caudal vertebrae look like if reduced still further, do you suppose? Like this, perhaps?





You want muscle attachments? How about the extensor coccygis muscle?! If the coccyx were movable, contraction of this muscle would move it. Do tell, Douglas, why there might be such a muscle attached, by design, to a solid fused piece of bone, that’s only there to help us crap?

To repeat for emphasis, it is a matter of location and morphology, not whether or not it is used. The coccyx is in the right place and made of the right structures to be a reduced tail. It even sometimes has a muscle to move it. Use is irrelevant.

Bwahaha! Oh do tell, Douglas, just how it is not vestigial? It wouldn’t be because it performs a slight function in the immune system would it? Once again for the slow ones at the back: vestigial does not have to mean useless, simply greatly reduced. Again, it is a question of form, not function.

Wanna argue that it is in some way a unique organ in the immune system? Bollocks. The Peyer’s patches in the appendix wall are part of the GALT (gut-associated lymphoid tissues) involved in the immune system, sure. But Peyer’s patches are found throughout the wall of the small intestine, not just in the appendix. The same amount of GALT could be produced by simply lengthening the intestine a little. (How much GALT is involved anyway?)

Contra the ‘it was designed’ argument, even if a pocket were required for some reason (instead of a longer intestine), why is it a pocket with a shape so easily blocked, with drastic consequences? It is ‘vermiform’, ‘worm-like’: a narrow dead-ended tube. Because of this ‘design’, it very frequently (eg 7% of the US population) does become blocked. When this happens, the gut bacteria (you do know that 50% of all the cells in our bodies are gut bacteria, yeah?) can invade the wall of the appendix, leading to it rupturing. This is often lethal, even these days with antibiotics.

So the appendix’s design kills people. The immune connection is a piece of misdirection, for whatever tissues are in it, they could be accommodated in a less dangerous structure.

TTFN, Oolon

[ June 14, 2002: Message edited by: Oolon Colluphid ]</p>

Duvenoy

"Strange. I wonder why all the merely "stinky" pre-skunks weren't all gobbled up by the "great horned owls". Or did the pre-"great horned owls" develop a lack of sense of smell in response to the stench of their favorite meals, slow and non-climbing, but stinky, pre-skunks?"

Very simple. Skunks are prolific and their relitives are quick moving, scretive, and generally hard to catch. "Pre-skunks" would have been no less difficult to get a talon on.

A sense of smell is limited to only a very few avians, mostly carrion feeders (as far as I know). The turkey vulture, very common in the US, is a prime example. Interestingly, the even more common black vulture lacks it.

doov

Mageth

Strange. I wonder why all the merely "stinky" pre-skunks weren't all gobbled up by the "great horned owls". Or did the pre-"great horned owls" develop a lack of sense of smell in response to the stench of their favorite meals, slow and non-climbing, but stinky, pre-skunks?

In addition to what Duvenoy mentioned, speed and climbing are of little use against great horned owls, who "ambush" silently from above and, since they can fly, going up a damned tree ain't gonna do stinky no good.

Skunk spray also irritates the eyes and skin, so it might serve some defensive purpose even against owls.

Further, skunks are found all over the new world. Great horned owls aren't. It's possible that skunk scent developed in an environment where great horned owls weren't present or weren't a major predator.

[ June 14, 2002: Message edited by: Mageth ]</p>

hezekiah jones

Clever oxymoron, Douglas.