I, too, am naive. So evolution is about "advancement--toward something better" but is not "goal-oriented." "Better-adapted" I can understand, but "towards" seems to imply a goal. "Improvement?" Could Cruzan (or anyone else) clarify, please?
WT ----- Original Message ----- From: "Mitch Cruzan" <[email protected]> To: <[email protected]> Sent: Friday, May 14, 2010 8:50 PM Subject: Re: [ECOLOG-L] facts, laws, and theories > Your question reminds me of the difference between science education > as it should be vs. science education as it is. There are equations as > simple and elegant as those describing the effect of gravity on an > object that describe processes of evolution. The trajectory of a allele > frequency in response to selection can be described with predictability > and simplicity of the same order as those equations in basic physics - > pick up any introductory textbook on population genetics and you will > find the answers there. > > The key thing is that Mendelian inheritance provides us with a > logical and predictable framework to start from. Adding the effects of > say, selection, to departures from the Hardy-Weinberg expectation then > comes down to simple algebra that most any high-school or beginning > college student could understand. Does it gloss over complications? > Yes, of course it does, just as the the simple equations of acceleration > under gravity ignore effects of the atmosphere, drag ratios, and many > other things. So the response to selection can be dampened by lower > heritability just as the acceleration of the object can be slowed by the > atmosphere. The mathematical foundation of evolution is just as simple > and complex as that of physics. > > I do not blame you for being naive about the existence of this body > of theory, but blame our science education system that has been crippled > by zealots who scream at any inclusion of evolution in biology - > including the simple effects of selection on allele frequencies in > populations (not to mention migration, genetic drift, and mutation). > > Can we boil down the 'Law of Evolution' to a simplistic form that > everybody can understand? Sure! The 'Law of Gravity' is about things > falling - everything falls, right? The law of evolution, at its core, > is about change - change is inevitable, or as Bill Clinton was fond of > saying, "change is good." Evolution has permeated our culture to be > associated with change -advancement - towards something better > (evolution is not goal oriented). This is just as inaccurate as the > common understanding of the 'law of gravity' (everything falls down). > So everything about the Law of Evolution is just as simple, predictable, > complex, and inaccurate in colloquial understanding as of the Law of > Gravity. > > Glad we had this little chat. > > Mitch > > [email protected] wrote: >> Mitch Cruzan wrote: >> >> >Perhaps it would be more clear to people if we referred to >> >>> the 'law of evolution' rather than using the ambiguous word 'theory.' >>> >> >> "Laws" in the physical sciences state simple, repeatable observations. In >> general, such a "law" may be summarized in a mathematical statement and the >> statement may be used to calculate the value of one or more variables when >> others are known. Though most laypersons misunderstand it, the acceleration >> under gravity equation that high school or freshman college physics students >> learn is an example and represents the law of gravity. The theory of >> gravity, on the other hand, is considerably more complex, and as I >> understand it, it is a part of the "Grand Unified Theory" that physicists >> seek. >> >> How can evolution be so summarized? Can we make a prediction about a >> future evolutionary outcome? Can we craft an equation that models it in the >> simple way that the law of gravity can be modeled by an equation? Though >> evolution is factual, an appropriate analogy to physical laws that applies >> in the case of the theory of evolution is something like the Hardy-Weinberg >> principle, which states a simple relationship that can be repeatedly >> demonstrated, and can be used to accurately predict future allele frequency >> in a population. It does not constitute the entirety of evolutionary >> theory, and no single physical law constitutes the entirety of a given >> physical theory. >> >> At least that's how I understand the relationship of what are called "laws" >> to theory. I used to tell my students that a "fact" was something that was >> repeatedly observable, and that was generally understood to be true. I then >> stated that theories explain facts. Regarding evolution in this sense: >> Chimpanzees and other great apes share a considerable amount of >> morphological and genetic similarity with people. That is a fact. The >> theory of evolution explains those facts by invoking phylogeny. >> >> I would state further to my students that the theory of evolution (the >> explanatory model, still under development) explains the facts of evolution >> (observed natural selection of antibiotic existence by microbes, and >> observed interbreeding of domestic dogs and wolves for example). >> >> Now, if we want to substitute the word fact for theory in describing the >> concept of evolution to laypersons, then we'd be correct. Evolution is a >> repeatedly observed phenomenon, and the concept is generally understood to >> be true. I suppose what is known as a law in science is a fact, also, in >> that sense, but we can't summarize evolution with a single, simple model >> like we can a physical law. At least I can't. >> >> I hope this helps rather than hinders the discussion. >> >> David McNeely >> >> -------------------------------------------------------------------------------- No virus found in this incoming message. Checked by AVG - www.avg.com Version: 8.5.437 / Virus Database: 271.1.1/2873 - Release Date: 05/14/10 06:26:00
