Re: [asa] Finding Your Inner Fish

If all of this is true of humanity in general, then - as C.S. Lewis realized - it is true in particular of Jesus.

"He comes down; down from the heights of absolute being into time and space, down into humanity; down further still, if embryologists are right, to recapitulate in the womb ancient and pre-human phases of life; down to the very roots and seabed of the Nature He had created." [C.S. Lewis, Miracles (Macmillan, New York, 1947), pp.115-116. I've corrected what appears to be a typographical error.]

The idea of embryological recapitulation fits very nicely with Irenaeus' idea that Jesus recapitulated the history of humanity. I wonder if anyone ever suggested that to Haeckel!

Shalom
George
http://home.roadrunner.com/~scitheologyglm

  ----- Original Message -----
  From: Nucacids
  To: Randy Isaac ; asa@calvin.edu
  Sent: Saturday, April 18, 2009 11:39 AM
  Subject: Re: [asa] Finding Your Inner Fish

  Hi Randy,

  The embryonic homologies emphasized by Haeckel and others focused on vertebrates, but the homologies we find between humans and invertebrates (and protozoa) was not expected.

  And it's not me saying this:

  When you think about all of the diversity of forms out there, we first believed this would involve all sorts of novel creations, starting from scratch, again and again and again. - Sean Carroll

  Much that has been learned about gene physiology makes it evident that the search for homologous genes is quite futile except in very close relatives. If there is only one efficient solution for a certain functional demand, very different gene complexes will come up with the same solution, no matter how different the pathway by which it is achieved. The saying "Many roads lead to Rome" is as true in evolution as in daily affairs. - Ernst Mayr

  And so to see that genes that are doing such profound things in the fruit fly - making head from tail, stomach from back, thorax from abdomen - are conserved, related in other animals . this was just not predicted by anybody. - Mike Levine

  the adaptationist paradigm of evolutionary biology seemed to imply that genes, whatever their molecular nature, would not be well conserved between distant organisms - Eugene Koonin

  It's a simple historical fact that such deep homology was not only unexpected, but expected not to exist. That this situation existed when people recognized homology between vertrebrate embryonic stages makes the story even more interesting.

  The Inner Fish is indeed cool, but it is the Inner Amoeba that takes us to a whole new level of cool.

  - Mike

    Thanks, Mike. Very interesting. Are you saying that ideas of homology in the embryonic stage waxed and waned in the last 150 years? Didn't Darwin put some emphasis on it while Haeckel over emphasized it. Then are you suggesting it was discounted and is now becoming more plausible at the protein level?

    Randy

      Hi Randy,

      "The title of his book reflects his perspective that humans contain the essence of 3.5 billion years worth of life. Our genetic structure reflects elements of all the other organic structures. He noted that in the past 15-17 years, many of the Nobel prizes in medicine and related biological fields have been for studies on worms and parasites and other small species. He inferred that many of the critical processes in our own bodies were reflected in the "lower" life forms and could be more easily studied there. He also spoke of the comparison of human and shark embryos and he showed the early similarities of analogous structures in these embryos. As a fish paleontologist, he has been teaching a first-year anatomy course to the U of Chicago medical school. He tells them that all the major human structures were all first seen in fish."

      Yes, this is all very cool. But it's better than this. If anyone would like to see single-celled amoeba form a multicellular life form before your very eyes, check out this:

      http://designmatrix.wordpress.com/2009/04/17/dictyostelium/

      The amoeba coalesce into a multicellular life as a response to stress. What's makes this so super cool is that they use the same circuitry the human body uses to respond to extreme stress: G protein receptor, G proteins, adenylyl cyclase, cAMP, and protein kinases. Humans use this circuit as part of their "fight and flight" response, where it is triggered by the hormone epinephrine (adrenalin). I don't know if these amoeba make or use epinephrine, but others do:

      http://designmatrix.wordpress.com/2009/02/02/the-neurotransmitter-toolkit/

      Someday I may write a book entitled, "Our Inner Amoeba" as these continual findings of deep homology enhance the plausibility of my particular front-loading hypothesis.

      BTW, I should also mention that such deep homology was not predicted to exist by the Modern Synthesis. On the contrary, it was predicted to not exist. Again, from Koonin's paper, "Darwinian evolution in the light of genomics":

      "Moreover, the adaptationist paradigm of evolutionary biology seemed to imply that genes, whatever their molecular nature, would not be well conserved between distant organisms, given the major phenotypic differences between them, as emphasized in particular by Mayr, one of the chief architects of the Modern Synthesis (21)."

      Or, as Mike Levine explained:

      "And so to see that genes that are doing such profound things in the fruit fly - making head from tail, stomach from back, thorax from abdomen - are conserved, related in other animals . this was just not predicted by anybody. At least nobody that I ever read. So this was very profound. It meant that there could be a common blueprint for all animal life on this planet.

      In the case of the discovery of common homeotic genes among all animals, there was a strong sense in the '70s and the '80s that embryonic development among different animals involved completely different molecules, completely unrelated. This was such a strongly held view. And so, yes, it came as a huge surprise not only to people like my mother who says, "My God, an earthworm and a mouse? An earthworm and me, sharing things in common?" But it came as a surprise to other scientists that there was this profound conservation of mechanism of building embryos among all these different kinds of animals."

      http://designmatrix.wordpress.com/2009/02/14/evo-devo-fits-comfortably-with-front-loading/

      - Mike

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Received on Sat Apr 18 12:08:40 2009