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Tuesday, June 3, 2014

Leaping Lizards: Saltation vs. Saltation: Jumping Grains vs. "Hopeful Monsters"

     A Smith friend (thanks, Dot!) sent this link to a University of California at Berkeley page which draws a timeline of evolutionary thought in a clear, spatial manner:




     For live links, see the page below:


    TIMELINE OF EVOLUTIONARY THOUGHT


     The graphic is particularly intriguing because it includes both biologists and geologists.

     The scientists are essentially grouped as non-Darwinians, Darwinians, and neo-Darwinians. And who doesn't enjoy a good Galapagos tortoise photograph:





      The branch which caught my attention was the "Hopeful Monsters" tied to Richard Goldschmidt. (Of course, this branch is still under construction at the Berkeley site)...But, the connection between "Hopeful Monsters" or saltation in evolutionary biology to saltation in geology was too enticing to pass up. Saltation is the jumping over quickly from one creature a la macromutations (in biology) or one grain (in geology) to another. Fast evolution, fast geologic change vs slow evolution, slow gradual geologic change.


     In general, both evolutionary biology and geology tend to change slowly over many generations or years. But there are times, as in the Scablands of Eastern Washington, where floods have occurred over a short time period (55 years at a time over a total of 2000 years) creating a landscape that changed relatively quickly:




      As to "Hopeful Monsters," relatively rapid changes due to macromutations were proposed by Goldschmidt in 1940. Many neo-Darwinians dismissed his ideas, however.
      
      On the subject of Goldschmidt, Donald Prothero in his book Evolution: What the Fossils Say and Why It Matters (2007) wrote:

"The past twenty years have vindicated Goldschmidt to some degree. With the discovery of the importance of regulatory genes, we realize that he was ahead of his time in focusing on the importance of a few genes controlling big changes in the organisms, not small-scales changes in the entire genome as neo-Darwinians thought. In addition, the hopeful monster problem is not so insurmountable after all. Embryology has shown that if you affect an entire population of developing embryos with a stress (such as a heat shock) it can cause many embryos to go through the same new pathway of embryonic development, and then they all become hopeful monsters when they reach reproductive age."

       A paper by Page et al in 2010, showed that the Mexican axolotl (Ambystoma mexicanum) could be classified as a hopeful monster as it exhibits an adaptive and derived mode of development that has evolved rapidly and independently among tiger salamanders. 

     In both biology and geology, periods of rapid change make sense.

      (It is unfortunate that some creationists have taken the "Hopeful Monsters" theory as meaning there are no transitional fossils and that "punctuated equilibrium" translates to no evolution. Punctuated Equilibrium is not the same thing as "Hopeful Monsters.")


     Leaping lizards! That's a pretty hopeful looking monster.

With all good things saltational and not, I look forward to your thoughts,

Steph
(aka Word Woman)







   

   




25 comments:

  1. Wondering if any creationist ads will appear on this post...Let me know if you see any.

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    1. There is a frac water analysis ad at the moment. Always a hot topic in CO - and with me.

      The fast change scenatio, in addition to slower, Darwinian-scale change, makes sense. It's much more obvious in geology, when you have things like volcanic eruptions that are sudden. I know how suddenly the creek behind our house changes its bed during a flood, as opposed to its general bank erosion pattern. We are just getting started on biology in this regard, as you say. I was thinking about epigenetics, as well, because gene expression can change much more quickly than the code itself.

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    2. Great point about epigenetics, Joanne. Glad you included that in your post...Do you have more to share about this topic? It's one I know little about.

      In general, I think about geology as a slow change operation over millions of years. Yet, quick changes like a volcanic eruptions and flood effects are, of course, a major part of geology as well.


      And thanks for the scoop on the ad. Insurance ad here.

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    3. Sorry for the delay in replying. I don't have in depth knowledge of epigenetics, but I have been seeing references to it more and more often, particularly when reading about obesity research. The nutritional environment in utero can cause certain genes to turn on or be suppressed, with live-long implications for metabolism and weight issues. It looks like this may be part of the reason that weight loss is not as simple as burn more calories than you eat. To complicate things further, it seems that some epigenetic changes can be inherited, especially because a female's egg cells are formed before she is born. So, for instance, the child of a woman who was in utero during a famine could pass on the epigenetic changes that happened to her as a result of the famine to her children.
      Joanne
      I'm having a bit of trouble getting this to publish, so thought I'd better put my name...

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    4. Really interesting post about epigenetics, Joanne. Thanks for writing.

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  2. To a physiologist, saltation describes the conduction of nerve impulses in myelinated axons. Action potentials travel relatively slowly down unmyelinated axons, but the insulating layers of myelin laid down by Schwann cells over many vertebrate neurons allow the action potentials to jump from one node of Ranvier (the space between Schwann cells) to the next, greatly speeding up conduction. In diseases that destroy the myelin, like multiple sclerosis, conduction is compromised with devastating effect. Here is a basic illustration of this idea.

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    1. jan, that was a wonderful link and graphic showing just what the myelin does and how the nodes are spaced. I didn't fully understand why MS was so devastating before. Saltation seems to be important in lots of situations in nature.

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  3. How far could you throw an axolotl with an atlatl?

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    1. Caption for that photo should be "She turned me into a newt!"

      Speaking of British accents, I wonder how far you could 'eft one of those without an atlatl? (I do like that word. It's a special treat to see it twice in 3 weeks -- it came up in a Jeopardy championship game with Ken Jennings, Brad Rutter, and Roger Craig on 5/16.)

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    2. It is a bit Newtonian. ;-)

      Atlatl is a great word...though I want to say atl-atl not at-latl. Have you ever used one? My son and I did with some Cub Scout adventure.

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  4. Sixth-grade Engineer Software Testing. You start by think about the stories...not the machines:

    http://www.smith.edu/news/campus-school-sixth-graders-testing-software/

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  5. This morning I was imagining scientists in the far, far distant future examining a fossilized, genetically modified cornstalk or some such, and puzzling over how such a thing could have come to be. Is that an impossible scenario (he asked hopefully)?

    I keep getting an ad for a 'brain-dead simple system' to save 90% on my grocery bill.

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  6. It would be great if it turned out to be impossible. But, I think that may not be the case, somehow.

    I am now getting an ad for a "Stem Cell Poster." Hmmmmmm.

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    1. SS,
      As Little Morpin’ Annie exclaimed, “Leapin Lizards!”

      We are lulled into thinking that evolution and our earth just “salameander” along like some aimlessly lazy stream. But noooo. Here comes… a waterfall! Rapids churning. Salmon jumping. Snails darting. Lords and lizards aleapin’!

      Very, insightful analogy between evolutionary biology and geology. I like the Bob Beamon-like leap you made to connect the two. Those insights are why I love logging on to PEOTS each week.

      No Creationism ads, just Computer game, bachelor degree program and Road Kill T-Shirt ads. (reminds me of a diner I once operated.)

      LegoLeaper

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    2. Thanks, lego. It's great to hear from you. Salameandering along, indeed!

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    3. Lego..and your description was electric!

      Btw, do others not get the robot capthcha on PEOTS? Far too easy to post quickly if one hits publish too fast.

      Microscopy equipment adverts now ;-)

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  7. I got one yesterday with "Creation or Evolution" as a headline. Or maybe it was "C and E", or "E and C", or "E or C", ... or "vs." ...
    Anyway, it was for danielfriedmannbooks.com. Apparently, he wrote a book attempting to reconcile biblical and evolutionary timelines. More to think through.

    I also got one for Doo Bop cosmetics. What happened there? Anyway, it's interesting to note that kosmetikos and kosmikos both derive from kosmos. What that says about beauty and truth and truth and beauty, I'm not sure. And where does Kramer fit into this equation? You guessed it ... more to think through.

    Aside from that, I've gotten a couple of ITT Tech ads, and, just now one for creative writing/ script writing for film, games, and animation from Full Sail University. The 'brain-dead simple' grocery-saving scheme seems to have backed off, and I'm glad. I was starting to feel just a wee bit insulted.

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  8. Paul, I haven't seen the Creation or Evolution one nor the Doo Bop cosmetics. Beauty and truth and truth and beauty ...and how about daisies, too? Very Cosmos politan thinking. Yeah, brain-dead simple would not be a lure for me, either.

    Good luck with your thinking. Let me know what percolates through. . .

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  9. Daisies? Are you referring to the CaliforniaPsychics.com daisy? I must admit that mouseover petal picker is kind of cool.

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  10. That's what percolated through, Paul? ;-) I found no daisy petal picker there...but I will admit to mixing Cosmos with Compositae.

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  11. I didn't find one there either, but they left a few here. They're gone, but Daniel Friedmann has returned [Man: creation & evolution -- followed by a link to his website -- followed by "Bible and science agree on timeline for appearance of Humans. Buy book!"]. Doo Bop still thinks I'm a good prospective customer, and now I get to Play Bible Trivia: How many were present at the last supper -- 13, 11, 6, or 12?

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  12. I'm going with > 13. Someone had to cook. Is that an option?

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  13. For a Saturday morning puzzle slice, check out Puzzleria!

    Most recent advert: Biodiesel Fuel Distributors

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  14. Why there will never be a list of every word:

    http://m.theatlantic.com/technology/archive/2014/06/there-will-never-be-a-list-of-every-word/372355/

    Interesting tweeting project also. One word every 30 minutes since 2007. It just "finished" with a Z word.

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