14 February 2008

Weekly sampler 6

I suppose I should report on the activities I mentioned in last week's sampler. Phil Keaggy was fun: the first set was a complete – and, I'm told, "verbatim" – rendition of the 1978 instrumental album The Master and the Musician. I'm neither an audiophile nor a musician, but I liked Keaggy's guitar and especially liked the band behind him. The second set included a little too much Christian pop for my taste.

U23D was great, but we all thought it was too short. And we wished the folks running the IMAX theater would have turned the sound up. (Way up. It's rock and roll.) But that just means we loved it. "Streets" was a high point, and the transition from "Love and Peace or Else" to "Sunday Bloody Sunday" (via Bono on a solo drum) was vintage U2 melodrama.

Saturday's Grand Dialogue keynote lecture by Howard Van Till was superb, and I'll post separately on my impressions of his talk. For now, I'll just note that while I'm a "traditional theist" who happily affirms creeds and confessions of historic Christianity ("tribal orthodoxy" to some) and therefore quite theologically distinct from Howard (or so it seems), I find myself in passionate agreement with just about everything he says. And besides, he reminds me of Bono:
The more you see the less you know
The less you find out as you go
I knew much more then than I do now.
– U2, "City of Blinding Lights"

I don’t know as much as I used to.
– Howard Van Till, 9 February 2008
Howard's remark, part of his response to an incoherently rambling "comment" from the audience after his lecture, drew significant applause. My post will include his extensive outline along with my impressions, and I'm told that audio and/or video will be posted on the Grand Dialogue site at some point.

Now some new morsels.

1. In a past Journal Club, I described work by Joe Thornton's group in which they "resurrected" ancient proteins and examined their properties, thereby assembling an evolutionary history of steroid receptors. Ian Musgrave at Panda's Thumb reviews a recent report that employs a similar strategy, looking much deeper into life's history.

2. Steve Martin at An Evangelical Dialogue on Evolution posts some typically thoughtful and informed reflections on Tony Campolo's Darwin/Hitler piece last month. He doesn't say what he thought of the exchange I had with David Opderbeck in the comments after my own post on the topic. I'm curious.

3. One way to avoid making a fool of oneself while discussing evolution is to understand the concept of a phylogenetic tree. Ryan Gregory has just published an article on the subject, in the online journal Evolution: Education and Outreach. Read it, and promise me you'll never claim that biologists believe that humans have chimps as ancestors. (Image on right: Darwin's first tree, from an 1837 notebook.)

4. Tuesday was Darwin Day, on the occasion of his 199th birthday. How did I celebrate? I think I spent much of that day working with cells and wrestling with DNA sequence analysis, but hey, every day is Darwin Day. :-) Last week's issue of Nature includes a somewhat more substantive tribute, an article by Kevin Padian, "Darwin's enduring legacy," in which he "looks forward to a season of celebration by outlining how Darwin’s ideas changed scientific thinking." The article touches on 10 topics that "hint at the magnitude of the man's legacy," and it's worth the trouble to get a copy if you're looking for an overview of the big ideas that are legitimately attached to Darwin's name.

I was drawn to the last topic: gradual change. Some of the most vituperative disputes in evolutionary science surround this concept. (Witness the recent eruption of rancor after Olivia Judson's piece on "hopeful monsters" and saltationism.) Padian notes that Darwin is correctly remembered as a proponent of gradual evolutionary change. Then:
But what did he mean by ‘gradual’? Most dictionary definitions have it as ‘slow and steady’, and this is indeed one meaning that Darwin used. There is another.
What is the other meaning? Well, consider the word: gradual. As in graded. Padian describes how Darwin noted the graded, stepwise aspects of geologic history as recorded on cliff faces. He described these transitions as "gradual," but did not mean that they were "slow and steady." Padian concludes that Darwin understood – and meant to highlight – both senses of the word 'gradual.'
This conceptual tension between ‘slow and steady’ and ‘step-like’ is the basis of one of the most important evolutionary ideas of the twentieth century: punctuated equilibria. This generalization is based on myriad fossil examples showing that the morphology of species may not change appreciably for much or most of their history, then alter relatively rapidly. If this turns out to be the predominant pattern of evolution in well-preserved fossil sequences, as now seems to be the case, Darwin’s view of the plurality of evolutionary tempos and modes will be vindicated.
Punk eek as Darwin's idea? I like it.

5. Just announced: the 2008 schedule for the Michigan Shakespeare Festival. All's Well That Ends Well and Julius Caesar. All's Well will be a new one for me. We're talking about a family vacation in Jackson. No joke!


T Ryan Gregory said...

Punk eek as Darwin's idea? I like it.

"Many species when once formed never undergo any further change but become extinct without leaving modified descendants; and the periods, during which species have undergone modification, though long as measured by years, have probably been short in comparison with the periods during which they retained the same form. It is the dominant and widely ranging species which vary most frequently and vary most, and varieties are often at first local—both causes rendering the discovery of intermediate links in any one formation less likely. Local varieties will not spread into other and distant regions until they are considerably modified and improved; and when they have spread, and are discovered in a geological formation, they appear as if suddenly created there, and will be simply classed as new species."

The Origin of Species, 6th Edition (1872), p. 408-409.

Darwin was a gradualist, but some inkling of the idea of punctuated patterns does appear in his work.

Steve Martin said...

Hi Stephen,
What do you mean I didn't say what I thought of your exchange? Of course I did: I said it was an interesting, spirited, and provocative discussion, and it helped me formulate my own thoughts. What else would you like to know? :-)

Looking forward to your thoughts on the Grand Dialogue.

RBH said...

Writing as an outsider, whenever I see "gradual" in connection with evolutionary change I always mentally change the term to "incremental," which much more accurately captures what I read Darwin (and most evolutionary biologists) to mean. And reading the original Punc Eek paper (here) I see no explicit abandonment of incremental evolution. Now Gould may later have wandered off the reservation, but at least in its beginnings, Punc Eek was no less incrementalist (at the level of the isolated evolving subpopulation) than Darwin or Mayr.