Proving Evolution in the Age of Genetics

It's impossible at any point: the smallest difference in DNA doesn't result in a change in species or even in variety.This begs the question of what is a species?

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we are limited in our ability to understand
by our ability to understand RebelAAmerican.Zen[Deist
{{{Buddha walks off laughing with joy}}}

not a closed loop. the linear progression is there with some more compatable with others near them and less compatable with others further away.certainly size fits into the equation, but you also have reproductive failures (sponaneous abortions and the like) where the mating just doesn't "take" (several examples already given).

I thought that ring species form closed loops with each sub-species able to breed with it's neighbors but not with species across the ring. there are seagulls that fill this bill ... I believe there was a thread on ring species>...Ring species as evidence for speciation
EvC Forum: Ring species as evidence for speciation

to be even more blunt: the kind of difference you see in the DNA between very similar varieties of, say dogs, is the same kind of difference that you see in the DNA between much more divergent species, such as between bacteria and human.there is no genetic differentiation into classes or any other cladistic organization based on the kind of change in the DNA. all there is in the DNA is a pattern of divergence over time ... evolution, by definition.enjoy.

increasingly it is evident that species is an arbitrary designation that was originally based on convenience form observed forms, that all such forms are in a continual state of change\transition and that each can be traced back to one ancestor through a series of changes small enough that the differentiation values of speciation do not apply. in this regard every living thing is a ring species in time.

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we are limited in our ability to understand
by our ability to understand RebelAAmerican.Zen[Deist
{{{Buddha walks off laughing with joy}}}

I do not recall reading or hearing it -- you are free to use it as it seems pretty generic (spontaneously generatable) to me.enjoy.