Re: News: Replaying evolution.

John Harshman wrote:

dkomo wrote:

Ye Old One wrote:

Replaying evolution
By Patrick Barry
June 2nd, 2008

http://www.sciencenews.org/view/generic/id/32801/title/Replaying_evolution_


Scientists show that happenstance mutations matter


WTF? The only thing this experiment shows is that *all* mutations matter, whether happenstance or not. Evolution is sequential. The way a species evolves in the future depends very much on how it evolved in the past. A fish will evolve as a fish because it followed the fish path in evolution in deep time. A fish won't evolve in the future like a mammal.

Duh!


Duh, indeed. Since a fish evolved in the past like a mammal, what exactly convinces you that another fish won't evolve like a mammal in the future?

You mean "evolved in the past *to* a mammal". Actually, the sequence was more like fish -> amphibian -> reptile -> mammal. The founder fish as it started down this long evolutionary trajectory was still a fish, or what passed for a fish in those long ago times, and evolved *like* a fish for relatively short time periods, a few hundred to a thousand generations or so.

Or are you just trying to invoke Dollo's Law, and are stating it poorly enough that I can't tell?


I don't know Dollo's Law.

If Stephen Jay Gould were alive today, he would be smiling. Maybe even
gloating.


No he wouldn't. Sorry.


He probably would. He was that sort of guy.


I mean he was smart enough to see that the aforementioned research didn't prove his replay thesis.

New research suggests that the famous evolutionary biologist was right
when he argued that, if the evolution of life were “wound back” and
played again from the start, it could have turned out very
differently.


This research shows nothing about the randomness of the mutations in those microbes.

This is all much ado about nothing.


Agreed. All that's shown here is that slight differences in initial conditions can result in big differences in evolutionary outcome. Is anyone surprised? Now in fact I think that's what Gould meant by "rewinding the tape of life". Obviously he couldn't have meant it as a literal analogy, since no matter how many times you rewind a tape, it still ends the same way. And a big effect from slight changes in initial conditions is exactly what "contingency" means.


If this is all Gould is saying then it is trivial. I'd be embarrassed to even mention it, let alone support it as some kind of important statement about life.

Let's take an example. Suppose the KT boundary asteroid/comet had never struck the earth. The tiniest of changes in its speed or path when it was still millions of miles from the earth would have caused it to miss the earth by a wide margin. Then the life forms we see today would be substantially different, and we probably wouldn't be here discussing it.

Duh! to the power of 10. Even I would agree with this kind of a contingent effect on life's history.

Thinking like this isn't science, however. It's little more than a amusing parlor game. Let's compare this kind of thinking to replaying the tape of human history, which is filled with innumerable "contingencies". Suppose Mrs. O'Leary's cow hadn't kicked over that lantern in the barn. Then Chicago wouldn't have burned down. Suppose that the U.S. carriers had been at Pearl Harbor when the Japanese bombed it. Then WWII would have proceeded completely differently and the U.S. might have lost to the Japanese.

These days Henry the VIII is quite popular. There's the acclaimed Tudors series on Showtime cable channel, and last Sunday PBS Masterpiece
Theater had the first part of yet another historical drama about Henry and his wives. Then there were the two Kate Blanchett movies about Queen Elizabeth, which were permeated by Henry's influence even though he was long dead.

I love this historical stuff and playing around with alternate histories. Suppose if we rewound and replayed the tape of human history, Cathrine of Aragon had given Henry a healthy male heir. Then Henry wouldn't have divorced her and fallen out with the Roman Catholic church. England would have stayed Catholic and Ann Boleyn and Sir Thomas Moore would have kept their heads. There would never have been a Queen Elizabeth because Henry's male heir would have gotten the throne. Likewise "Bloody" Mary, Cathrine's daughter, wouldn't had a brief reign as queen and burned all those heretics. Without a Queen Elizabeth, there wouldn't have been an Elizabethan Era and no Spanish Armada, and perhaps William Shakespeare's plays would have been lost in obscurity.

Great fun this replaying the tape of human history, as is replaying the tape of life. But both are fantasies. The evolution of life could only have taken a single path, which is exactly the path it actually did take.


--dkomo@xxxxxxxx





.

Relevant Pages

  • Re: News: Replaying evolution.
    ... A fish will evolve as a fish because it followed the fish path in evolution in deep time. ... You should also remember that, speaking cladistically, mammals *are* fish. ...
    (talk.origins)
  • Re: News: Replaying evolution.
    ... A fish will evolve as a fish because it followed the fish path in evolution in deep time. ... You should also remember that, speaking cladistically, mammals *are* fish. ...
    (talk.origins)
  • Re: News: Replaying evolution.
    ... A fish will evolve as a fish because it followed the fish path in evolution in deep time. ... You should also remember that, speaking cladistically, mammals *are* fish. ...
    (talk.origins)
  • Re: Basques discover the Grand Banks 1372
    ... the 'history' of sea fishing fur­ther back in time and thus to begin to ... fish were being caught and the latter how much marine food was being eaten.. ... increase in catches of cod, ... History is not what it used to be. ...
    (soc.history.medieval)
  • Bacalao
    ... one of the summer intern med-students in the lab was ... Italian descent) happened to mention salt cod. ... fish is deeply intwined in the history of the exploration of the New ... Strange History and Uncertain Future of the World's Most Coveted ...
    (rec.outdoors.fishing.fly)