Macro- vs. Micro-evolution

There's very little in here about Dr. Senapathy's theory. This is about the meaning of the words "macroevolution" and "microevolution."

I will save you a lot of reading: All you need to know is that "macroevolution" when used in the context of the Senapathy theory means long-term, non-observable changes, including natural selection and descent with modification. This is the extension of Darwin's theory that Dr. Senapathy says is wrong. Macroevolution does NOT include short-term, observable changes, including artificial selection and environmental adaptation (that's "microevolution") --there is no dispute in the new theory that those mechanisms work.

If you are a masochist, read on.


From Patrick O'Neil: There is NO distinction between MICROevolution and MACROevolution. The processes are identical - the only difference is one of accumulated extent and/or the nature of the genetic element, be it a gene, chromosome segment, whatever. A point mutation at one locus in one gene can have absolutely no effect on biochemistry and phenotype OR it can have drastic effects. A series of separate point mutations over time can act the same way. A transposition event can be innocuous or a major alteration. A recombination event of other types can be minor, major, or a fatal change. No difference between one and the other except in the deluded eyes of the creationists.


From Una Smith: Darwin observed large evolutionary change over geological time, and small to modest evolutionary change over ecological time (most dramatically in animals under intense selection by man). His brilliant idea was that the fundamental process underlying both was the same.

JM: His idea would be brilliant, I agree, if it was correct. The ideas that the Earth was flat and at the center of the universe were also considered simple and brilliant ideas in their time. The processes of macro- and micro-evolution are NOT the same. Dr. Senapathy at page 65: "Darwin had extrapolated the power of artificial selection in producing breeds to the power of natural selection in an extended geological time producing unique creatures with new genes and body structures. But neither artificial selection nor natural selection can ever extend beyond the confines of the closed permanent boundary of a distinct creature. And this was Darwin's mistake." That statement is surrounded by much discussion and supporting information.

Senapathy does not use the terms "micro" and "macro." You probably know the two as Darwin's special theory and general theory. Darwin assumed they worked the same way. In a search for "brilliance," you are ignoring much evidence of problems with the general theory. The process by which a moth's color changes is not the same process that caused flippers to "change" into feet.

Una: The problem is, indeed, to show precisely how the processes we observe to produce small changes to existing forms in ecological time can be scaled up to produce what seem to have been novel forms over geological time.

JM: That is not the problem ("to show how ... process ... can be scaled up") -- the problem is to understand how the small and large differences between organisms came about, and see if they are related. You then live with what you find out instead of trying "to show" that what you saw fits into a presupposed, single, simple theory. You are making the same mistake that Darwin did: making and assumption that two similar-appearing effects are caused by the same thing.

Una: Senapathy tries to solve the problem by sweeping vast amounts of messy evidence under his rug, and then trying to distract everyone by pointing out how neat and small his rug is. Sorry, but parsimony works by counting all the pieces of evidence not explained by a theory, not by hiding the evidence and counting the parts of the theory instead.

JM: You are ignoring "all the pieces," too. Senapathy's book is lengthy, and only a small fraction of his theory has been presented in detail here. You need to read his book before you can say he has ignored anything. Isn't that fair? The actual presentation of his theory takes a relatively small space in the middle of his book -- all the rest is showing how the observed facts and the new theory fit together and where those facts fail to explain the general theory. Nothing is being ignored.


From Patrick O'Neil: Oh for... For the second time. There is no difference between MICROevolution and MACROevolution. The underlying process IS IDENTICAL. It is merely predicated upon the particular mutation type in a particular location within a particular gene. The mutation can be a point mutation, a transposition event leading to a fusion, a gene duplication (which REALLY allows new, novel functions to develop without harming the host in many cases), and so forth. A point mutation may not do squat or it might so alter the resulting protein's conformation or function that it has drastic phenotypic effects. Same with ALL the other mutation types.

The ONLY thing required to initiate the formation of a new species of whatever is a minor change in an isolated population's mating biology: for animals that experience estrous, this can mean a VERY minor alteration in fertile cycles such that they can no longer mate with other related creatures. It can mean an alteration in egg receptors such that only a specific variant of sperm ligand can productively bind. There are ANY number of simple means by which a new species can come into being and once one does, it can go in a direction morphologically and behaviorally independent from its precursor species.


From Una Smith: (quoting JM) [Darwin's] idea would be brilliant, I agree, if it was correct."

Una: It is brilliant regardless of whether it is correct. And vast amounts of research over the past century have failed to disprove it, hence it would appear to be correct.

JM: "The processes of macro- and micro-evolution are NOT the same."

Una: This assertion contradicts a great deal of well-documented fact. Furthermore, Keith Robinson has shown that the evidence in favor of this assertion, as given by Senapathy and repeated by you, is based on serious errors of math.

JM: "Darwin assumed [microevolution and macroevolution] worked the same way."

Una: Not so. Darwin's Origin of Species is devoted to establishing the hypothesis that they work the same way, and giving evidence in support of this hypothesis.


From Roger Gary: I just picked up Michael Denton's Evolution: a Theory in Crisis. He also distinguishes Darwin's "special" from his "general" theory. I am only a lowly undergrad, but in 37 semester hours of paleontology, biology, and zoology I have never even heard such a distinction mentioned. Rather odd to run into it twice in two days. Has any non-creationist ever proposed such a distinction?

It seems to me that arguing that microevolution is qualitatively different from macroevolution is like arguing that no matter how many letters of the alphabet I add, change or delete, I could never transform On the Origin of Species by Means of Natural Selection, or the Preservation of Favored Races in the Struggle for Life (I love that title) into the King James Bible.


From Neil Foglia: [Does anyone worth listening to consider] macro-evolution to differ significantly from micro-evolution? Gould and Eldredge have argued that "macro-evolution is not micro-evolution writ large." Yet I do not recall any significant alternative view that they offer as to why this would be so.

They consider macro-evolution to be the area of evolutionary theory that is concerned with an actual speciation event that goes beyond mere>micro-evolutionary changes. That is a more pronounced change than amino acid substitutions or gene mutations. Just how big of a change they are looking for I don't know, but suspect that it would be along the lines of drastic morophological adjustments.

By recent exposure to some of the latest thinking on punctuated equilibria, I am leaning to the view that what they have proposed does not differ that significantly from the views already contained within the modern synthesis. P.E. appears to mandate geographic isolation in order for speciation to occur. Mayr has held to similar views and in fact had been criticized for making geographic isolation a requirement of speciation. About the only difference that I can see right now, is that P.E. also requires that this isolation be in conjunction with small population numbers. In other words, geographic isolation alone, when applied to a wide spread and numerous population, may not result in drastic evolutionary change.

The marine record offers many examples when this appears to be the case. If the populations of a species is numerous, then the degree of separation is on the micro-evolutionary scale. From this one might infer that when the census number of the isolated populations are low, then the changes may become more pronounced. Why this is so is not clear to me, so what follows is mere speculation on my part.

A smaller population isolated from a larger group would have less genetic diversity, but shouldn't they also be more genetically conservative? Perhaps their genotypes are not as coherent do to the fact that rare mutations can spread more quickly in a smaller population. If this is the case, then by enabling micro-mutations to take hold more quickly in smaller populations macro-evolution becomes possible. I think!


From Phil Nicholls: In Evolution and Entropy: Toward A Unified Theory of Biology by DR Brooks and EO Wiley, microevolution and macroevolution are distinguished from each other on the basis of reversibility. They make an analogy between macroscopic and microscopic processes in thermodynamics. Thus in microevolution there is no "arrow of time" to the extent that the process can be run backward. Hence in the classic example of Industrial melanism when the pollution of the industrial revolution was reduced and trees resume their natural coloration the frequency of mottled to black moths changed again.

Macroevolution is identified with speciation. Once speciation has occurred the gene pools are permanently separated. Selection and adaptation after speciation has occurred will increase genetic divergence which in turn will increase the amount of morphological divergence. Hence morphological divergence is a result of speciation but not the cause of speciation.


From Shane McKee: Is there any qualitative difference between "macro" and "micro"? I don't think this has been demonstrated at all. All the differences seen at the "macro" scale turn out to be the same differences, qualitatively, as those seen at the "micro" scale. Nobody uses those archaic terms, "micro" and "macro" any more, do they? Your usage of the terms seems to stem from the levels either side of the species barrier, which is a shaky one at best to use for fundamental distinctions.

Actually, there's a hell of a lot more controversy about gravity [than evolution]. The controversy is in how it works. We know a lot of the mechanisms of evolution, from the bottom up, but know practically nothing of the underlying mechanisms of gravity.

Darwin's theory was that change was produced in populations due to repeated selection of favorable variations. Genetics and molecular biology have shown how this works. There is no controversy that natural selection works. Random genetic drift also plays a part. No big controversy here.

It's worth trying to understand the theory (i.e. the rules and principles) of evolution, and also to learn some molecular biology. Then you'll see that at the most basic level, there's not a lot of difference between a human and a cat.


From Shane McKee: Dr. Senapathy seems to fail to understand what the genetic code actually does in the development of an organism. The DNA is not a blueprint for an organism, of which bits can be lifted and laid willy-nilly, but, to use Richard Dawkins' analogy, more like a recipe. The finished product is due to the complex unfolding of the process, which is damned difficult to predict in advance.

JM: I don't know why you say this, other than perhaps because I have not described Dr. Senapathy's theory in enough detail for you to understand it. Senapathy's book is full of discussions about developmental genetic pathways and references to undisputed genetic theory having to do with how genes control the development of an organism. However, if you can be more specific with a question, I'll try to respond.

Shane: There is no specific genetic blueprint for the forelimb of a coelophysis, in the sense that you could just change that one section and get, say, a bat-wing. It's a complex emergent phenomenon. This is in direct contradiction with the notion of re-use.

JM: Again, I don't understand why you think this about reuse. Reused genes form only part of new organism -- there is also a random amount of new DNA. The reused genes are random, too.

Senapathy can no more demonstrate the formation of life in the lab than you can objectively demonstrate macro-evolution.

Shane: Do you mean speciation? That has been demonstrated objectively in fruitflies, and even Darwin himself showed some pretty impressive results with pigeons.

JM: Senapathy has no problem with that -- those things are part of what I term "micro" (and maybe for the last time :-). Artificial selection and many adaptations do occur. These do not involve new body parts or new genes (see below).

Shane: By "macro-evolution," what do you mean? Species level? Genus level? Phylum?

JM: Yes, I agree that the "macro" term is causing problems. Senapathy draws the line this way: body parts and new genes. If two organisms have different body parts or a totally new gene, then they came about independently. There is one exception, and that is if the developmental genetic pathway for a body part has been turned on or off (through changes in protein levels, for example) in some later descendant. But that does not involve a significant change in the genome, just a change in expression or the level of expression.

By the way, "micro" and "macro" are not terms that Senapathy uses anywhere in his book -- I used them because they made sense to me, but I now regret doing so because of the confusion.

Shane: Any organism can be thought of as occupying one particular point in multibillion-dimensional genetic space. Evolution supposes a branching path to any location thus-far attained. Dr. S's notion presupposes the trial of just about every point de novo. Genetic data clearly favors the former, and to my mind actually falsifies the latter, or at least makes it very unlikely.

JM: You are not leaving room for the commonalities that Senapathy predicts. Reuse of parts of successful genomes will generate similarities, and they will be tree-like.

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