[Taxacom] On genera, splitting and ranking

Kim van der Linde kim at kimvdlinde.com
Sat Jul 13 12:05:41 CDT 2013

I think age is a useless criterion, because it assumes two things:

1. Age == evolution
2. Same age == same number of generations

Obviously, a shorter generation time implies more generations and thus 
more genetic change. Evolution and change depends not only in the number 
of generations, but also on the need to adapt to novel situations, 
bottlenecks, and a load of other mechanisms that affect the realized change.

I think that what we are doing now is mostly perfectly fine.


On 7/13/2013 10:38 AM, Frank.Krell at dmns.org wrote:
> "Yes, Hennig once did propose a testable criterion for rank, that is, age of origin. However, everyone, including Hennig himself, rejected that criterion."
> Chris, would you remind me where he did so? I just cannot remember that he did, but it is long ago that I read all his theoretical works (in German).
> "Age is a wonderful and scientific criterion for rank. If we had such, then we could easily propose that higher Diptera (Cyclorrhapha, a suborder) is the same as birds (Aves, a Class) and far more diverse [Yes, the little creatures with narrow specialization generate more species, than larger more generalized predators, etc.]. But these kinds of scientific questions are not now possible due to the distorted system of classification we have and used."
> Isn't it amazing that a clear and useful criterion, probably the only phylogenetically justifiable criterion to define rank meets with so much resistance, rendering comparisons beyond one's small research domain so difficult?
> Tradition (Aves is a class, Scarabaeidae is a family) is so much more important for emotionally heavily invested scientists than scientific reasoning.
> And, of course, we have many paraphyletic species, but we should not have paraphyletic higher taxa. There is no reason to let the pendulum swing back to pre-hennigian times.
> Frank
> Dr. Frank-T. Krell
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