Thanks again CDT,
Response to #254627
I'm confusing nothing. Neither of these "theories" has enough in common with Darwin's proposal to be equated therewith. The definitions given are of more recent origin, and there's no trace of the struggle required by Darwin's version of "natural selection". Darwin's attempt was more understandable. Had he merely said "things change", I suspect even his atheistic comrades would've blown him off.
The "struggle to exist" was one of his observations -- more offspring were created in each generation cycle than were needed to replace the existing population, yet the existing populations did not increase in size in the same proportion, and some decreased. His conclusion was that natural selection - the fact that some individuals were better suited to survive and breed than other versus limited natural resources (environmental factors) - would be inevitable, resulting in the change in hereditary traits in populations from generation to generation. His "theory of evolution" (although he never used the word, it was adapted later from embryologists) was that descent with modification was sufficient to explain the diversity of life as we know it.
"Things change" is a simplification, a strawman, as it doesn't include what changes nor how it changes: in evolution what changes is the hereditary traits, and how they change is that some are better suited for survival and breeding under prevailing environmental conditions than others, and thus will become more "popular" within the populations.
There's a question that begs to be asked: if Darwin's story, or any of the subsequent forms of evolution were satisfactory, why would you be undertaking these rewrites? Would you mind explaining some of the shortcomings?
Sometimes you need to word the same ideas in different ways to reach people that don't understand the basic concepts. I'm sure you've run across instances of this in school and the work place.We also do know more about the mechanisms of how hereditary traits change than Darwin did - he basic knew that "things change" but did not know that the mechanisms involved mutations and genes.
You could say that his theory predicted genetics, and the subsequent discovery of DNA and genetic mutations are just another validation of his original theory of Descent with Modification.
Purebreeds are reproductively isolated by the humans in their environment. As any reproductive isolation is sufficient under your chosen definition, they are separate "species".
My definition doesn't really involve the definition of species, rather it is concerned with the process of speciation. At some point in the process we would recognize different species, but there is usually disagreement on when that occurs. If it makes you feel better to call them "species" go ahead, that doesn't affect the rest of the argument in the slightest. The biological definition of species is rather mutable, but the real issue is the process of division of populations into non-breeding sub-populations and that this allows subsequent genetic divergence of the populations. Certainly that is the case with the purebred dogs, just as much as it is with the Asian Greenish Warblers. As I said above, dogs could be considered a ring species as well.
What you have is the accumulated effect of an environmental condition causing a difference in selection in different populations, however if you remove the environmental effect you will see interbreeding and the mixing of genes. This demonstrates the temporary effect of environmental factors on selection of populations, however you will note that the merged population will have different genes to select in subsequent populations than exist in the wolf population. Those traits were selection neutral during the isolation environment.
Now why don't I offer a competing hypothesis? Might make the thread a little interesting, I think.
You should call this the "god did it" theory, as it is just as testable. What we are talking about is using the evidence that we have of change in life over time, and explaining them with known (observed) amounts of variation within populations. The test is with the evidence, not with the imagination.
Response to #254662
This grows more unsatisfactory the more I look at it. A deceased lifeform is reproductively isolated, so any time something dies we can call it a different species. Best we know, all formerly living things are unable to reproduce.
This is confusing individuals with populations -- when populations die they become extinct and there is no remaining species.
Evolution does not occur in individuals, but in populations of individuals that have differential success in surviving and breeding and passing on their hereditary traits.
Enjoy.
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Note: my time is limited, so I only choose threads of particular interest to me and I cannot guarantee a reply to all responses (particularly if they do not discuss the issue/s),
and I expect other people to do the same. Thank you for your consideration.[/color]
