Friday, May 06, 2005

Creation Science IV - Why I am a Jerk

In the most orthodox of Darwinisms, everything is precisely mathematical:
  • A small percentage of the time, through the random process of genetic drift, a given organism's genetic make-up will deviate significantly enough from its immediate progenitor that there is a modest physical effect.
  • In a small percentage of this small percentage, the change will add to the organism's chance of surviving, or reproducing, or both.
  • Over time this small change will establish itself in the genotype of the group by the working of probability, to be succeeded by another small change.
  • Rinse and repeat.
  • A sufficient number of small changes results in speciation.

Voila! Evolution by Creeps. (Say hello to Richard Dawkins, approximately) For me, at least, this is one of the most elegant, beautiful formulations in science, and I mark it as a loss of one of my rivers out of Eden that I am no longer among the orthodox.

A competing theory is Punctuated Equilibrium (Stephen Gould et. al.), which holds that species tend to remain stable, and that evolution occurs rapidly and in RELATIVELY short periods of time. Well, despite the order in this entry, the Creeps actually started the ennui-dispelling epithets by calling this Evolution By Jerks. They averred that it amounted to a misreading (more accurately, I think, it should be termed an over-reading) of accidents of the fossil record that resulted in apparent gaps in transitional forms.

Of course one might simply state that it was God the Designer, for his own inscrutable purposes and unfathomable timing, Who steppeth on the evolutionary gas every so often, but still requires a fair number of generations to go from a to b. Have I not discussed that already? As a side note, one instance where we have plentiful transitional forms is in the homo genus and its immediate ancestors - largely because we as a hamans are most interested in our immediate relatives, so time and money is spent in that direction. Interesting that humans - the case of greatest concern to the Creationists - is a case where orthodox Darwinism works very well. Incremental improvements in brain capacity, manual dexterity, and upright posture would be features of random-ish mutation and natural and sexual selection.

So why am I a Jerk? (shuddup, Cyndie)

1. Core Philosophy of Science: Predictive (not explanatory, read CS II) power of the fossil record: EBJ would say that, despite millions of years difference between estimated dates of fossils within an era (not fossils in the same find), you will be more likely to find yet another T Rex or, say, an Allosaurus, than an entirely new form transitional between the two (example only - beats me if these two are even related.) You are more likely to find either a Triceratops or Styracosaurus than a common ancestor other than yet another Protoceratops. EBC doesn't account for this, and an alternate explanation that somehow these species were more likely to hang out in fossil-producing circumstances than intermedate forms doesn't provide any testable predictions.

2. Mathematics: Richard Dawkins (a Creep) cited a mathematical study that showed that a small set percentage improvement of survivability/reproduction of randomly generated changes could lead to enormous cumulative differences. True, but inevitably: some changes or sets of changes will lead to sharply higher rates of rates of s/r than others - favorable adaptations could not have identical values. This, in turn, would lead to sharply faster or slower changes of the genotype.

3. Environment: One-time events occur that sharply change the odds of survival and/or the specific traits that would be selected, like catastrophe, an out-of-control feedback mechanism in another competing/predatory/preying species or migration to new environment (e.g. an island). These would accelerate the mathematical process within a process, but would be even more significant if there really is a meta-genetic trait that makes random mutations more or less likely in a given population. A mutation in favor or mutation. In a stable environment, a tendency to mutation (weak genes?) would generally be selected out since most of mutations are disadvantageous. A radically stressing changed environment means that organisms willing to try something, anything have a better chance of producing a solution, that will be reinforced in the s/r feedback mechanism.

Some open questions:

  • Is genetic heritage entropic or inert? In other words, does a species need evolutionary pressure to maintain complexity, like a kite, requiring some kind of need-to-survive wind to stay aloft, or does a genotype at rest stay at rest? Do eyes vanish in cavefish and the ability to fly in birds in predation-weak environment reflect only the cost to maintain those traits when they become no longer advantageous, or also a tendency toward simplication when not disadvanteous?
  • Does parallel evolution as in placental and marsupial animals like flying squirrels (which reminds me, do the immutability-of-species people think Australia is some kind of Divine pun - that He knew that people would call it Down Under and he thought putting pouches on ALL the mammals, otherwise an incredible coincidence, was really a good joke?) give us something against which to test mathematical models of evolution, much like twin studies are used to separate hereditary and environmental factors in humans?
  • Are there any larger-organism-to-gene feedback mechanisms that actually work, without getting all vulgarly Lamarkian? I can't find (sorry Tom) the recent news story on an organism's ability to repair misinherited genes, sort of the opposite or complementary to the meta-mutation idea above), but it was suggestive.
  • If there is a meta-mutational tendency, are there multiple varieties that favor selective and specific changes within a genome (say, on the set of genes that controls the size and shape of forelimbs), or only generally?
  • Can mathematical models (Heinlein the glib fascist said "If it can't be expressed in numbers, it's not science - it's opinion.") resolve some of these issues, bearing in mind that, as in geology, superhuman time frames are key to evolutionary science.