How do you define the word Evolution?

Good Morning Davidjay. More on luck and chance.I can think of one type of evolution that does not rely on luck and chance. That is plant and animal breeding, which is a form of MICROevolution. This has been practiced for thousands of years and is mentioned in the Bible with Jacob’s goat breeding. Breeders don’t need to know anything of genetics but by selecting for desirable characteristics and against undesired ones they produce a change in allele frequencies in the population over time.A consequence of this is that the purebred population will usually have less genetic diversity than the original population. Undesirable alleles have been eliminated by the breeder, so in a sense this could be regarded as devolution rather than evolution.We have accidental done this with antibiotics to produce resistant strains of bacteria and it’s worth looking at this more closely.Frozen samples from the Franklin Expedition have shown that even long before Penicillin was isolated bacteria had a very small proportion that was antibiotic resistant. Antibiotic use then could select for this trait rapidly producing resistant strains by microevolution.But where did these resistant individuals come from? They were probably produced by mutations that, in the absence of antibiotics, were detrimental. This is chance and luck. This is why they were in such small numbers since natural selection would have constantly weeded them out. Only when antibiotics came into use did these defects provide a net benefit. This is also why when an antibiotic is discontinued the bacteria population will gradually lose resistance.Say the antibiotic requires a certain binding site to be effective. Bacteria with a defect in this site will be resistant, but it is still a defect rather than an evolutionary advance, hence devolution.[edit] Here for example is a recent study on "Experimental evolution of resistance to an antimicrobial peptide" which is consistent with the above.
Experimental evolution of resistance to an antimicrobial peptide - PMCEdited by CRR, : Added reference provided by Dr Adequate.

Dredge, it is an example of microevolution in that it is a change in allele frequency in a population over time. This is quite similar to development of antibiotic resistance that I used as an example earlier.It also applies to insecticide resistance, Trinidad guppies, Darwin's finches, and many other examples of "evolution".

He says that when he doesn't have an Adequate reply. I have gotten it several times.

The problem is that it can be evolution depending on the definition of the word! That is why this topic is "How do you define the word Evolution". Strangely many of your critics have not posted their definition yet.In your example with the redheads There has been a change in the allele frequency in the population in that a lot of genetic information, for different hair colours, has been lost. According to the definition used by population genetics that is evolution, or what others outside the field would call microevolution.But you are right, no new alleles or genes have been created so the result is the variability in the gene pool has been lessened. Evolution by genetic loss must eventually result in extinction. I would extend this to say that speciation is step towards extinction.

Brief certainly, but not much of an explanation. Perhaps a specific example will help. Do those mutations arise in response to antibiotic use or independently? How does this tie in with the results from the Franklin Expedition?[Hint: Read my posts for some helpful information ]

Coyote,
Can you substantiate that claim that creationists have invented the term "evolutionists"? This sounds like the discredited claim that Creationists invented the terms micro- and macroevolution.
According to dictionary.com the word was first recorded in 1855-60; evolution + -ist; and is proudly used by evolutionists such as Karl W. Giberson.If you can't a retraction would be in order.

Thanks Doc, I have amended my message 141, EvC Forum: How do you define the word Evolution? , using this as an example.

So you're retracting then? Don't worry, I won't inform Retraction Watch.And I did give an example of an evolutionist who uses the term for himself. A few minutes on an internet search engine will turn up others.

Pardon my ellipsis. Samples of bacteria obtained from the frozen remains of the Franklin Expedition, well before medical antibiotic use, showed that a very small proportion of the bacteria already had resistance to several antibiotics.Similar results have been found with other preserved samples of pre antibiotic era bacteria.On the other hand where an antibiotic is discontinued the bacteria gradually lose resistance.When are you going to post YOUR definition of evolution?

So you did, although it is dated 28/3/17. That's good. There is nothing in that definition that I, as a Young Earth Creationist, would object to. If that's all evolution is you can call me an evolutionist.

It shows the trivial nature of your definition. Adding a black ram to a flock of white sheep will produce heritable changes in the population. That's evolution? It makes no claim for origin of species let alone common ancestry.Compare my definition; Evolution is the theory that all the living forms in the world have arisen from a single source which itself arose naturally from an inorganic form. I have clearly stated the claim of common ancestry which necessitates the formation of many new species within new species to form genera, families, and higher orders. It also necessitates heritable changes and appearance of many new genes.Demonstration of a heritable change in a population does not prove evolution.[edit] You could change it to a definition of microevolution; that works.Edited by CRR, : As marked.

PaulK, you have a point."Dr. Nelson observes a pattern where until recently, evolutionary biologists protected common descent against the evidence of its own inadequacy. He gives as one example variant genetic codes something that ought not to be possible under the standard picture of a single tree of life." Variant Genetic Codes — Another Reason Biologists Are Thinking Twice | Evolution NewsSo I could change the definition to; Evolution is the theory that all the living forms in the world have arisen from one or a few sources which arose naturally from an inorganic form. However I'm sure many would argue that despite variations in the genetic code the commonality out weighs this and would suggest a single source.

Perhaps for clarity we should call the Doc's definition Creationist Evolution to distinguish it from other definitions.

No, that is a definition used in some places by some scientists; and quite a poor one as I have said. You don't speak for "science".Just as one example Jerry Coyne gives a quite different definition in "Why Evolution is True". Population genetics uses a different definition.Adding a black ram to a flock of white sheep will produce heritable changes in the population. First by gene flow when the ram is introduced, then by a change in allele frequencies over time as the ram gets to work.Edited by CRR, : second "change" deleted in last paragraph.

Ah, the Peppered Moth, poster child for evolution.It probably was a mutation, a large insertion, although perhaps the dark variant had simply not been reported earlier.Whether a mutation is beneficial is dependent on environment. Some could be detrimental in all environments, some beneficial in all environments, and some beneficial only in some environments.In the case of the Peppered Moth it appears the dark variety was initially beneficial since its numbers increased and it became the dominant variety, but then the numbers decreased so that the white variety became most common, in which case the mutation became detrimental. Or perhaps it was neutral and we just observed genetic drift.Perhaps it is like the sickle cell trait which is a loss of genetic information preventing the proper function of red blood cells but which has some net benefit in malaria prone areas. Even where malaria is prevalent the proportion of the defective allele never rises to more than 20% because of detrimental effects.