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GREBE AFFINITIES



WRT the affinities of grebes, Matt Troutman writes...

> S&A have argued that they are the members of an ancient lineage 
> with not close living relatives based on DNA-DNA hybridization.  

Sibley and Ahlquist were inordinately fond of using this phrase (i.e. 
'they have no close living relatives'). They used it for coliiforms, 
for parrots, for grebes, for some aberrant anseriforms, for 
cuckoos... In the literature you will read the same thing being said 
for other unusual taxa, e.g. _Neofelis_ (the clouded leopard). 

FACT IS - - if (a) you accept the evidence for organic evolution, and 
(b) you therefore think that all organisms are related to each other 
by way of descent, how on earth can any organism _not_ have a close 
relative???!! (Of course, 'closeness' is usually objective - 
molecular clocks notwithstanding!). In other words, grebes, or 
clouded leopards, or bizarre Australian ducks, or whatever, *must* be 
more closely related to some other sort of animal that they are to 
all the others. Thus it is false to state that any taxon 'has no 
close relatives'. 

Bought to you from the Brad Livezey school of phylogenetics.

"The road from reptiles to birds is by way of Dinosauria to the 
Ratitae. The bird 'phylum' was struthious, and wings grew out of 
rudimentary forelimbs" - - Huxley, 1868

DARREN NAISH
darren.naish@port.ac.uk