Re: Frogfish and `long-distant goal[s]' (was: Re: tagline)
On Thu, 09 May 2002 12:48:52 +0000, Andreas Peterson wrote:
>>>SJ>Why would a `blind watchmaker' start modifying *one* line of fish
>>>>*under water*: [...]
>>>when it didn't need it (other fish are doing fine), such that its
>>>>existing fish spine and fins bone and cartilage to make the basic
>>>>ground-plan of the shoulder-arm-hand-fingers and the pelvis-leg-foot-
>>>>toes that was the basis for all amphibian and land vertebrate
>>>>shoulder-arm-hand-fingers and pelvis-leg-foot-toes ever since?
>>AP>Allow me to direct Stephen's attention to Zimmer (one of the
>>>persons quoted in the text omitted) and his suggested function of this
>SJ>Thanks to Andreas for the Zimmer quote below, which book I do not
>>I am finding it hard to work out if Andreas is my opponent or not.
AP>I can understand this. I have read Zimmer's book, and when reading Stephen's
>argument that Acanthostega's preadaption to terrestrial life did not "look..
>like ... the work of a blind
>watchmaker", using quotes from one of Zimmer's articles, I wondered why I
>hadn't caught this myself when reading "At the Water's Edge".
Would Andreas recommend this book? Perhaps he can give us a brief
overview of it?
AP>So I went back to Zimmer's book and found the place where he is discussing
>Acanthostega, in order to see what he made of this preadaptation to land. In
>a passage not quoted, he retorically asks: "What advantage could possibly
>nudge some fishes toward a tetrapod body in a place where they already did
>so well?" (p. 91), and then proceeds to discuss "[a]n answer of sorts" - the
This "`answer of sorts' - the frogfish" would only be relevant if the
"the frogfish" had developed pectoral and pelvic girdles and the
connected those structures with arm and leg bones like the tetrapods
did. But they haven't.
AP>And now I notice that Zimmer also mentioned them in one of the articles
>quoted by Stephen:
>"If Acanthostega's ancestors lived underwater, it follows that
>fish must have evolved into tetrapods for life underwater. This
>idea has occurred to different scientists at different times.
>It occurred to evolutionary biologist James Edwards in the
>1970s. He was studying the locomotion of salamanders to
>understand how early amphibians walked. "I went to an aquarium,
>and I saw these strange creatures walking on the bottom; their
>pectoral fins really had the appearance of tetrapod limbs,"
>says Edwards. The creatures were antennariid anglerfish, best
>known for the lure they dangle to attract prey. Edwards
>contacted an expert on anglerfish who confirmed that these
>particular fish did indeed walk on their fins in the wild. ...
>And these weren't the only fish to turn fins into limbs,
>Edwards discovered. The sargassum frogfish, which is a close
>relative of the antennariid anglerfish and lurks in the dense
>seaweed forests of the Sargasso Sea, grabs seaweed stalks and
>swings along like a trapeze artist rather than trying to swim
>through the thicket. "A tetrapod could have evolved limbs to
>move around underwater in these ways," says Edwards." (Zimmer
>C., 1995, "Coming Onto the Land", Discover 16:118-27.
This is just playing with the word "limb".
AP>In the past, I have noted Stephen's very well-researched answers, as well as
>his discussions of arguments I would myself have given up on, so, not seeing
>any problem with the scenario proposed by Zimmer, I was curious as to what
>Stephen thought of it.
>I would not have a problem with Darwinism not being able to explain this (in
>fact, given what else I have seen, I *expect* it not to be able to), and so
>I would not characterize myself as an "opponent" of Stephen. However, since
>I was quoting Zimmer (whom, I guess, most likely *would* be an "opponent"),
>I believe it was fitting for Stephen to attack my arguments *as if* I was
>the fiercest "opponent".
Thanks to Andreas for this clarification.
AP>That being said, I was extremely impressed by the answer given. As I said
>before, Stephen has persuasively argued points that I would myself have
>conceeded, and this seems to be yet another example of that. :-)
>Therefore, rather than writing "agreed" and "conceeded" after each of
>Stephen's points, I just note my agreement with him, and move on to the next
Thanks again to Andreas.
We can now hopefully put this part of the post behind us.
"If the origin of the protein alphabet is a headache, making the elaborate
characters of the nucleic-acid alphabet is something of a nightmare.
Nonetheless, all of them have been made one way or another by the
reaction of chemical substances that might, if you're an optimist, have
existed on the early Earth. One component of all the nucleic-acid
characters is a sugar molecule which can be created by dishing out rough
treatment to formaldehyde. Another component is a so-called nucleic-acid
base. There are four types of these in DNA, and four in RNA - they are like
the crucial brushmarks that distinguish otherwise identical characters. The
nucleic-acid bases can be fashioned from reactions involving hydrogen
cyanide or a small molecule called cyanoacetylene. But all of these
syntheses require indelicate loading of the dice, for example by using
concentrations of the reactants greater than could have been mustered on
the early Earth. (Ball P., "H2O: A Biography of Water," , Phoenix:
London, 2000, reprint, p.209-210)
Stephen E. Jones sejones@... http://members.iinet.net.au/~sejones