The scientific community does not consider the origin of life as part of evolutionary theory. That theory simply assumes the prior existence of life, and is directed to an explanation of how life evolved after that. It does not presuppose either the absence or the presence of a creator, or of the validity or non-validity of the concept of naturalism.
    Within that context, no less elite an organization than the National Academy of Sciences (NAS), via their National Science Education Standards (NSES), says about evolution:
1. Natural Selection and its evolutionary consequences provide a scientific explanation for the fossil record;
2. The great diversity of organisms is the result of more than 3.5 billion years of evolution that has filled every available niche with life forms; and
3. The millions of different species that live on earth today are related by descent from common ancestors.
    Not much question there. The consensus of the “hundreds of scientists and educators” involved in establishing the NSES is that, although nobody really knows how it all came about, it is quite clearly known fact that we are all direct, lineal descendents of that very first life form. And this is what our education system is saying must be taught to our children. A high school student simply cannot be considered scientifically literate unless s/he fully understands and believes these standards. And s/he will be tested to assure that s/he does in fact know these scientific facts before s/he can graduate.
    Well, clearly there is no doubt, proven almost every day in the laboratory and in breeding farms, that, via natural selection, existing species can and do evolve in response to changes in the environment. A biologist I knew, just for fun kept vials of live fruit flies on his mantle at home and regularly evolved new forms of fruit flies simply by changing the environment in those vials. But he felt it important to note that he never evolved anything but more fruit flies.
    To better organize and simplify this discussion it seems worthwhile here to establish some usable definitions:

    Other evolutionary mechanisms: genetic drift, migration and mutation have been proposed as mechanisms that might produce the slow, long-range evolution that is said to have produced the various species.
Thus natural selection, requiring interbreeding, is primarily applicable to evolution within populations capable of interbreeding (species), and is the basic mechanism for micro-evolution. Micro-evolution, by this mechanism, is well-supported both by scientific experiment, such as selective breeding, and by millions of fossils in the fossil record.
    Natural selection is also considered one of several possible mechanisms for producing new species. One species (A) may get widely separated geographically (Aa/Aa), in locations with significantly different environments. In one of those locations that species (Aa) might micro-evolve (over a long period of time) into a form (Ab) which is now so different that it could no longer mate with it’s original species (Aa). By definition, (Ab) would be considered a new species. Such a process requires such large physical separation and long times that it is difficult to envision production of many new species by this mechanism.
Other theories of long-range, macro-evolutionary mechanisms are similar to this application of natural selection in that they could produce major evolutionary changes but only if given enough time. There are no well-established, verified scientific proofs of these mechanisms, and there are no firsthand accounts to be read. In addition, during these long, slow transitions from one major species (Aa) into another (Ab), there should be left behind fossils of intermediate species (A-x-b), roughly as plentiful as the original (Aa) and final (Ab) species. The fossil record shows tens of thousands of fossils of the major species (Aa/Ab) but almost none of the intermediate forms (A-x-b). Neither are there well-established, verified scientific explanations for this gap. While many studies show close correlations between fossils of similar species, it must be recalled that “correlation does not prove causation”.
    The mechanism of micro-evolution (natural selection) seems well understood, and is well established by direct experiment and by a voluminous fossil record. So it seems that the first of the above NSES can be considered scientifically correct, so long as it is fully understood that “the fossil record” cited is almost exclusively that of the history of micro- and not that of macro-evolution.
    Unfortunately, it does seem that many “pro-evolution” scientists, including many of those involved in development of the NSES, use the strong evidence for micro-evolution to “substantiate” and strengthen the concept of macro-evolution. This seems clearly a false extrapolation. Both NSES (2) and (3), above, make this grand, overextended statement.
    The controversy over evolution certainly seems to be one of those situations where the scientific method should be rigorously invoked. At least today it seems that we are not able to adequately understand and demonstrate evolution of one major specie from another, like a robin from a couple of fruit flies. Therefore, strict application of the scientific method would show that it is not appropriate within science to say that continuous, incremental evolution from that very first form of life was the prime mechanism for the broad species diversity we see here on earth today. Unless and until we can repeatedly cause and control the evolution of species from each other, science simply has to admit that such between-species evolution cannot be considered more than unsupported hypothesis or conjecture.
    It seems especially important, then, to define and agree on what we do and do not really know (the current “box”):