Replies

RE: Cease being uncertain that you could call that evolution through the theory of natural selection of genetic variation, because it is exactly the mechanism that Darwin described.

OK, let’s understand what I am trying to say. By Darwinian evolution, I mean DESCENT WITH MODIFICATION THORUGH NATURAL SELECTION.

What did he mean by that ?

I take it to mean in your response that one can demonstrate a beneficial mutation … with laboratory organisms that multiply rapidly, and indeed such experiments have shown that rare beneficial mutations can occur. For instance, from a single bacterium one can grow a population in the presence of an antibiotic, and demonstrate that organisms surviving this culture have mutations in genes that confer antibiotic resistance.

Now, Darwinian Evolution at least posits that Various different modern species share a common ancestry. Since the time of the common ancestor, the divergence into the various modern species has involved changes much greater than microevolution. This is the idea of “common descent.”

I am really not sure whether you accept this notion. I think there is excellent evidence for common descent of some groups of species. If you do not accept common descent, at least for the cases I cite, I would be interested in hearing what alternative interpretations you can offer for the observations I cite.

I believe the point you want people reading this FR thread to EVENTUALLY accept is ( although you did not state it, I think it can be implied by your posting zeal ) —— All of the nucleotide discrepancies between modern species, or between a modern species and its ancestral species, arose as a result of random mutation (including gene duplications, insertions and deletions caused by naturalistic processes) and natural selection, without the intervention of an “intelligent designer.”

So, Darwinian theory, which is the prevailing theory of evolution, teaches that this development occurred through random heritable variations in the organisms followed by natural selection. I shall denote the word evolution used in this sense as Darwinian Evolution. When evolution is discussed for popular consumption, it is most often Darwinian Evolution.

I hope I am not misrepresenting your understanding.

So, having explained my understanding of your terms, I have to qualify my terms now.

Mutation and selection can lead to “microevolution,” i.e., small changes in gene frequencies that follow an environmental shift and leave a population on average more fit to cope with the new environment. I think you accept this, since I think it corresponds to what you mean by Evolution ( as you use the term ).

I hope I am not misunderstanding you because my response is based on that understanding of the Darwinian evolution as it applies to bacteria.

My response to this is that many scientists observe that mutations leading to antibiotic resistance FAIL the test of representing the mutations necessary for Darwinian evolution ( as described above).

All antibiotics are derived from microorganisms. Recall the story of the serendipitous discovery of penicillin by Alexander Fleming in 1928, when he noticed that his plate of Staphylococcus bacteria was clear in the vicinity of a bread-mold contaminant. The mold was found to produce something that could lyse and kill the bacteria. That something was a molecule later named penicillin.

Afterwards, other antibiotics were found to be produced by other microorganisms, such as soil bacteria. Soil has long been recognized in folk medicine as a cure for infections.

The antibiotics produced by these microorganisms serve them as a defense against attack by other microorganisms. Some microorganisms are ENDOWED (who and what endowed them, is not the scope of this response) with genes that GRANT resistance to these antibiotics.

This resistance can take the form of degrading the antibiotic molecule or of ejecting it from the cell.

Unfortunately for human health care, the organisms having these genes can transfer them to other bacteria making them resistant as well. Although the resistance mechanisms are specific to a particular antibiotic, most pathogenic bacteria have, to our misfortune, succeeded in accumulating several sets of genes granting them resistance to a variety of antibiotics.

The acquisition of antibiotic resistance in this manner qualifies as evolution ONLY IN THE LIMITED SENSE that it is an ADAPTIVE hereditary change.

It is an example only of BUILT-IN ADAPTATION ( I know evolutionists dislike terms that imply design, but I can’t think of another word for now). It is NOT the type of evolution that can make something ELSE out of a bacterium.

The genetic change is NOT the kind that can serve as a prototype for the mutations needed to account for Darwinian Evolution. The genetic changes that could illustrate the theory must not only add information to the bacterium’s genome, they must add new information to the biocosm. The horizontal transfer of genes only spreads around genes that are ALREADY in some species.

It turns out, however, that a microorganism can sometimes acquire resistance to an antibiotic through a random substitution of a single nucleotide.

Streptomycin, which was discovered by Selman Waksman and Albert Schatz and first reported in 1944, is an antibiotic against which bacteria can acquire resistance in this way.

BUT.... although the mutation they undergo in the process is beneficial to the microorganism in the presence of streptomycin, it CANOT SERVE AS A PROTOTYPE for the kind of mutations needed by Darwinian Evolution.

The type of mutation that grants resistance to streptomycin is manifest in the ribosome and DEGRADES its molecular match with the antibiotic molecule.

This change in the surface of the microorganism’s ribosome prevents the streptomycin molecule from attaching and carrying out its antibiotic function. It turns out that this degradation is a LOSS OF SPECIFICTY and therefore a LOSS OF INFORMATION.

The main point is that Darwinian Evolution cannot be achieved by mutations of this sort, no matter how many of them there are.

Darwinian Evolution cannot be built by accumulating mutations that only degrade specificity.

So, am I saying that your understanding is wrong? No.

I am saying that any conclusion AT THIS POINT IN TIME IS PREMATURE.

The mutations needed for Darwinian Evolution have NEVER been observed.

No random mutations that could represent the mutations required by Darwinian Evolution that have been examined on the molecular level have added any information.

The question is: Are the mutations that have been observed ( e.g. Bacterial resistance) the kind Darwin’s theory needs for support? The answer turns out to be NOT YET. NOT AT THIS POINT IN TIME. THE EVIDENCE IS INCONCLUSIVE.

Many have lost information. To support Darwinian Evolution, one would have to show MANY examples of random mutations that ADD INFORMATION (emphasis on MANY ).

Unless the aggregate results of the genetic experiments performed until now is a grossly biased sample, I must WITHOLD VERY STRONGLY ANY CONCLUSION that Darwinian evolution is an explanation of how life developed from a single simple source. And bacterial resistance IS NOT ( NOT YET IF YOU PREFER ) an example that one can cite.

Which is why I responded to the other poster as I did. One need not be a Darwinian Evolutionist to understand biology ( and to teach it in school for that matter ). That was the original statement that sparked our exchange.