[Taxacom] SUSPECT Re: Molecules vs Morphology

[Mario Blanco]

Commonly accepted among biologists in general. That definition has 
absolutely no conflict with morphological evolution. As I said, all 
morphological evolution is determined by changes in the genetic makeup 
through generations. I am myself more interested in the morphology, but 
even paleontologists have to acknowledge the genetic basis of 
morphological evolution. The reason that this definition does not 
explicitly mention morphology is because you can have genetic change 
through generations without any obvious change in morphology or 
behavior. And yes, that is still evolution.

Of course, when you study evolution of extinct taxa you have to rely on 
morphological evolution and rarely (if at all) can study the underlying 
genetic changes, but that doesn't mean they didn't occur. The logical 
assumption is that all morphological changes were determined by genetic 
changes. And of course, you can have artifacts, like when different life 
stages or sexes are mistakenly taken as different species, always a risk 
with extict taxa (and any poorly known extant taxa for that matter).

If you define evolution in terms of morphological change, then you have 
to be careful to explicitly indicate that such change must be heritable 
(to avoid Lamarckian implications). And of course, "heritable change" 
implies that it is dictated by the genome.


Bob Mesibov wrote:
> Mario Blanco wrote:
>
> "But evolution itself is defined as change in the genetic makeup of a population through generations (this is a widely accepted definition of evolution)."
>
> Ouch. Widely accepted among phylogeneticists, maybe, but paleontologists would disagree. Also all those who, like me, have a rather more richly textured picture of evolutionary history than a set of gene trees.
>