[Taxacom] New systematics book
kinman at hotmail.com
Wed Sep 11 12:26:04 CDT 2013
> Say, if extinction is a part of speciation, then taxa are temporally isolated. That is, every age has its own set of taxa, some the same as other ages, some diffeent, some shifted or shifting their adaptive regimes or stochastic trait allotments.
Agreed. By the way, if I could have lived in the Jurassic, I would have probably classified birds as just a peculiar family of dinosaurs in Class Reptilia. In the Cretaceous, I would have probably classified birds as a peculiar, but major, Order of Class Reptilia. However, the end-Cretaceous extinction killed off all the dinosaur intermediates, birds radiated enormously, so a present-day classification justifiably recognizes them as a distinct Class Aves.
And when the very first eukaryotes arose, I would have probably classified them as a very peculiar family of bacteria or archaebacteria (certainly not an Empire or Superkingdom). Who would have thought such weird organisms would radiate into all the protists, higher plants, and higher animals (an extinction event at that time might have meant that they never did). Yes, every age does have its own set of taxa, but only a very select few radiate (in form, life style, and/or in numbers) to produce higher taxa in later ages.
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