Thanks again CTD.
These "theories" are not the same. The second one lists "Observation (2): some of the differences are hereditary (genetic, genotype), some are due to environmental effects (affect development, phenotype), and some are acquired by the organisms (behavioral, learned, individual traits, memes)." The first only lists heriditary differences.
You are confusing the evidence that the theory is based on with the theory - in both cases they say that evolution and speciation can explain the diversity of life. This is basically the same theory of evolution scientists have used ever since it was first presented by Darwin. That variation and natural selection would cause descent with modification, and that this was sufficient to explain the diversity of life as we know it, was Darwin's original insight.
First Statement (#254503):
Theory: these mechanisms are sufficient to explain the diversity of life as we know it, from the world around us, natural history, historical record, the fossil record and genetics.
Where the mechanisms are evolution and speciation.
Second Statement (#254552):
Theory: this is sufficient to explain the diversity of life we see in the world today, in historical accounts, in the fossil record and in the genetic evidence.
Where "this" included the observations and conclusions that show that evolution and speciation are essentially inevitable, and will continue to occur as long a life exists. The changes in the genes are permanent (fixed) once speciation has occurred, while the effects of environment and behavior are temporary and can be lost at any moment. They are included in this fuller statement of the supporting structure behind the theory of evolution because they are also part of the process of natural selection, just as weather and cosmic catastrophe are part of natural selection.
I also noticed that the dog example doesn't seem to work, as the chosen definition of species in "theory" #1 makes each breed a species. The definition has other problems. For example, when does one say the tumbleweed becomes a distinct species from the Russian thistle?
Not really, because the different breeds are not fully isolated reproductively from each other or the wild wolves, and will gladly cross breed when allowed to run free (b reeds are also often bred back with other breeds to change the mix of mutations available for further selection). "Purebred" stock does, however, demonstrate amply the ability of even a little isolation to show remarkable changes between populations. One could argue that the Great Dane and Chihuahua would find breeding difficult, and would appear to represent extremes of a ring species like the
Asian Greenish Warbler. Like the rate of evolution, the rate of speciation would depend on selection pressure and opportunity for divergence.
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]
