[quote]throttle132 wrote:
Tom, Sorry but these are examples of MICRO-evolution not MACRO.
The warblers remained warblers. They did not change into bald eagles or aardvarks. Only a truly religious person (one who believes something based on faith) can extrapolate that if variations within species and sub-species can occur, then wholescale changes way up the taxonomic tree can and have happened.
Macroevolution is generally used by creationists to define “evolution that has not been observed.” In the scientific literature, it is a deliberately vague term. The deliniation between so called micro and macro evolution is one that I would be interested in having defined.
Since you’re having a tough time here, let me help. As defined by The American Heritage Dictionary of the English Language, Fourth Edition
Copyright 2000 by Houghton Mifflin Company:
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Microevolution - Evolution resulting from a succession of relatively small genetic variations that often cause the formation of new subspecies.
Macroevolution - Large-scale evolution occurring over geologic time that results in the formation of new taxonomic groups.
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It’s not THAT difficult. The first is observable and testable and therefore a scientific fact. The second is sheer speculation without one single solitary shred of scientific evidence.
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You proved my point perfectly. I claimed that creationsists generally define macroeveolution as evolution that has not been observed. You then present me with a definiton of macroevoultion as LARGE SCALE evolution occuring over GEOLOGIC TIME. Do you not see the absurdity of asking to directly observe and test this??
If you are talking about macroevolution in terms of the divergence of higher level taxa over evolutionary time, then that is obviously not something we can directly observe or test. But if you accept the process of speciation, soemthing we can observe and test, then why would macroevolution not be possible?
I will assume that you are not kooky enough to believe that the earth is 6,000 years old. Are you telling me that speciation over a few hundred thousand, a million, or even billions years would not result in new taxa? How many speciations can a given organism undergo until until it has macroevolved??
Different taxonomic distance estimates can be inferred with respect to the degree of relatedness of high level taxa. Genetic markers and sequences are especially valuable in this regard and can generate very plausible phylogenetic trees for higher level taxa. They are testable to the extent that they are supported by other independent lines of inference such as the fossil record.
With respect to macro-evolution of higher taxa, there is perhaps no definitive testability at this time. But we sure have the tools to accumulate a lot of independent lines of evidence that, in many cases, converge on a ‘most likely’ phylogeny for particular groups. It’s the best existing procedure for approximating actual cladistic relationships.
Most creationists would now like to retreat to a defense of creation acting ONLY at higher level taxa. Unfortunately for them, molecular biology is quickly quantifying degrees of relatedness among families and orders.