Our Sunday Guest: Steven Schwartzman, shares his thoughts (and photos) on Convergent Evolution.   4 comments

In another lifetime that’s still intertwined with the current one, I found myself drawn to things mathematical. In high school half a century ago I bought a copy of the anthology Fantasia Mathematica, edited by Clifton Fadiman. The book was the first paperback edition, dated 1961 and bearing a cover price of $1.45, though I most likely bought it second-hand for considerably less, as none of the teenagers in my circle were rich. One of the stories that Clifton Fadiman included in his book was “Inflexible Logic,” written in 1940 by Russell Maloney, about whom I knew nothing further till now, when an Internet search turned up this, from Volume 4 of The World of Mathematics (which I also have had on my bookshelf for decades): “Maloney was a writer of short stories, sketches, profiles, anecdotes, many of which appeared in The New Yorker magazine between the years 1934 and 1950. He conducted for several years the magazine’s popular department, ‘Talk of the Town,’ and claimed to have written for it ‘something like 2600 perfect anecdotes.’ He died in New York, September 5, 1948, at the age of thirty-eight.”

And now here’s the passage from Maloney’s story that’s relevant to this post:

“Six chimpanzees,” Mr. Weiss said. “It’s an old cliche of the mathematicians. I thought everybody was told about it in school. Law of averages, you know, or maybe it’s permutation and combination. The six chimps, just pounding away at the typewriter keys, would be bound to copy out all the books ever written by man. There are only so many possible combinations of letters and numerals, and they’d produce all of them—see? Of course they’d also turn out a mountain of gibberish, but they’d work the books in, too. All the books in the British Museum.”

In other words, in a world of infinite possibilities, even six chimpanzees, if given an infinite amount of time at six typewriters—and an infinite lifetime each—would eventually type meaningful books by pure chance. The idea wasn’t original with Maloney, but it’s through his story that I first became acquainted with it so many years ago.

Now let’s apply the idea to botany. Imagine all the species of plants that exist or have ever existed. Of course plants in the same family, by the very fact of being in the same family, are bound to share various traits, and it’s from those traits that we can sometimes encounter a species that may be unknown to us, but which we immediately recognize is in certain ways akin to a sunflower, or a poinsettia, or a mint. These resemblances are there because all the species in a family presumably diverged from a common ancestor, some or many of whose genes all the descendants have carried with them through ages so vast we can’t really conceive them.

That’s only to be expected, assuming that biologists apprehend evolution correctly. But now think of the parable of the chimpanzees. Given enough time, two plants belonging to very different botanical families and therefore unrelated to each other, except insofar as all life forms on earth are primevally and at least minimally related, may by chance alone develop a common feature. We call the [presumably random] process that leads two unrelated species to end up sharing a trait convergent evolution.

Here’s an example from my own little world of the plants native to central Texas. One of my favorites to photograph over the past decade is Clematis drummondii, a climbing vine that belongs to the Ranunculaceae, or Buttercup family. What makes the plant fun is the swirling masses of silky fibers it produces after its flowers get fertilized, as I’ve shown in my blog on July 23 and July 25. Not much fun for most people is giant ragweed, Ambrosia trifida, a tall and erect member of the Asteraceae, or Sunflower family, though it belongs to a tribe of the family that doesn’t produce sunflower-type flowers, as you can see from my post on September 16. What makes giant ragweed so un-fun is the giant amounts of pollen it releases each fall into the air, and therefore also—as we live and breathe—into the nasal passages of allergic people.

And the point of convergence between these two otherwise so different plants? It’s the way they branch. Compare the first picture, of Clematis drummondii, with the second, of Ambrosia trifida, and I hope you’ll be as struck as I am by the similarity.

© 2011 Steven Schwartzman

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Thank you so much, Steve for this great article, your time and care, and these magnificent photos.   Please come back, again, soon.

You can find Steven Schwartzman in my blog roll; or go directly to: http://portraitsofwildflowers.wordpress.com/

 

Thanx for stopping by.  See you soon.

Forageporage

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4 responses to “Our Sunday Guest: Steven Schwartzman, shares his thoughts (and photos) on Convergent Evolution.

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  1. Pingback: First guest post « Portraits of Wildflowers

  2. Excellent explanation & illustrations. Thank you.

  3. Pingback: Poverty weed fluff « Portraits of Wildflowers

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