Letter from Frank Snively
Science – January 2005 – Colorado Central Magazine
Some scientific facts
To the editor,
The letter written last month by Ide Trotter regarding “honest science,” took George Sibley to task for a variety of statements. George can refute the message as he sees fit, but it would be well to present facts as they are used by the scientific community, at least as regards biological evolution.
(Trotter’s letter also mentions Cosmic evolution, i.e. the origin and formation of the Universe as we see it. However, that is a separate issue which can be the subject of another letter. We note here that there are puzzles. Such subjects as inflation and Dark Matter and Negative Energy are needed to explain what we see when we look at the sky, even though they don’t fit in with conventional general relativity and quantum mechanics.)
To begin the discussion of biological evolution, we’d better really define the subject. Evolution itself, i.e. the change of species with time, is as much a certainty as anything in science. Even a true believer that everything began in 4004 BC would be compelled to accept that all sorts of fossils were placed in the Earth, if only to misguide us. What is subject to interpretation are the mechanisms by which those changes took place.
And the descriptions of mechanisms are subject to change and updating, without destroying the concept of evolution. For example, Darwin himself was ignorant of genetics in any detailed sense — Mendel came along well after Origin of Species — so certainly any “Darwinian” (Trotter’s word) mechanisms are long since superseded.
Darwin’s notion of gradualism was based on the idea that small changes in organisms accumulated over many generations. Geologists at the time had come to recognize that the earth had to be hundreds of millions of years old (the age now up over two billion years as more knowledge has accumulated). That gave ample time for variations to accumulate and produce new species. Darwin was aware that in small isolated populations, the changes could occur rapidly; his observation of the finches in the Galapagos was convincing. In spite of that observation, the general concept of “gradualism” came to be interpreted as “slow and continuous” by both supporters and opponents of Natural Selection. Change in species and populations was a steady process, not interrupted by spurts.
Certainly many biologists, if pressed, would have admitted that there was no good reason for the assumption of gradual and continuous change. However it was Steven Jay Gould, together with Niles Eldredge, who emphasized that there was NO significant evidence for uniform rate of change. To be sure if conditions did not change, the mix of species would remain about the same, or change gradually, as had always been tacitly assumed. But, if conditions changed and new ecological niches opened, there would be a proliferation of new species. Gould coined the term “punctuated equilibrium” to describe the new point of view. It was rapidly accepted by biologists once it was called to their attention, a circumstance assisted in no small way by Gould’s eloquence in explaining the concept, and his accumulation of supporting evidence.
Please note that the above paragraph contains the description of the basic mechanism for “punctuated equilibrium.” Basically, environments change irregularly. Populations also change irregularly. Trotter would have us believe that the mechanisms are not understood, but they are actually straightforward, (well they are to me, anyhow). In a steady situation, the species are well adapted to the circumstances, and variations are usually weeded out — there is no selective advantage to changing the characteristics of a well adapted population. However, if changes in circumstances occur, there is room for change of characteristics, and in an extreme case, the “keepers of the old ways” will go extinct.
DNA a computer code? (The next issue raised by Trotter.) Hardly, at least not in the conventional sense. No computer, and no computer program, has a mix of promoter and suppresser code in constant action. For a simple example, how does a liver cell know to be a liver cell, while a muscle cell goes about the business of contracting? They both have exactly the same DNA, after all. The oversimplified answer is that certain parts of certain chromosomes are activated and other parts are suppressed, based on circumstances. As to the question “Where did it come from?” the basic answer is “All over.” Unless it produces a harmful effect, a DNA fragment tends to stay around. And there is a mixture of foreign DNA from other organisms. Nature was doing what is today called “genetic engineering” a billion years ago. When a new environmental challenge comes along, some of the fragments which lay dormant for most of that time may change just a bit and help the descendants of the challenged o
Finally, there are plenty of challenges to scientific orthodoxy both within and without the scientific community besides The Skeptical Environmentalist : Measuring the State of the Real World. Bjorn Lomborg’s book was foolishly rejected, not refuted (though some parts could have been), and since his message was welcomed by upholders of the status quo; it became quite the rallying cry of those who preferred to keep drilling for oil or ground water, burning fossil fuels, cutting down forests, spraying pesticides and disliking the Kyoto Accords. As a minimum, it had the salutatory effect of reminding scientists to put “error bars” on their analyses and recommendations. There have been a paucity of any other similar works since The Skeptical Environmentalist appeared. Has the well gone dry?
Trotter seems to imply that The Skeptical Environmentalist was unique. Of course that simply isn’t the case. Another challenge to scientific orthodoxy, and my personal favorite, concerned “global winter”. The original paper was known by some as 7 et. al.’s and Carl Sagan (Sagan agreed with the position of the authors, and agreed to co-sign to lend significance to the paper; unfortunately, he didn’t check the computations). It was literally true that many academic community members who questioned the methods and conclusions of the paper were told “Oh so you favor nuclear war” and had trouble getting their questions and objections published. (Shades of today’s message “Oh you’re not supporting our troops; then you ARE supporting terrorists.”) It took several years for more complete and objective analyses to appear in scientific journals. Other examples will be furnished on request.
And finally a personal comment on “punctuated equilibrium”: I once had Steven Jay Gould as a student of mine, though I have to admit the subject was Physics, not Evolutionary Biology. He was always very focused and able to do several things at once, and do them very well. I’ve always had a bit of a gift for gab, but Gould’s ability as a wordsmith, compared with my own, made it seem as though he came from a different planet. Gould is now dead, and for interpretation of modern work on evolutionary biology, I have to rely on my son, a vertebrate Paleontologist, for explanations. He has reviewed this letter and made several suggestions; I take sole responsibility for the accuracy of the paraphrases contained herein.
Frank Snively
Buena Vista
