Which is not valid and is easily manipulated. It is totally subjective and not science that is why evolutionists love it. The biological species concept is non-subjective and is therefore valid. More importantly, as regards to the evolution question, it is the only valid criteria since evolution claims that species transform themselves into different species. It is the only criteria which takes into consideration what is essential for a species.
Again, there is no evidence, so far as I am aware, of a morphological species
Repeating the lie. I already showed you proof that the coelacanth, the morphology of the coelacanth, has not changed in some 380 million years in my previous post to you to which this is a response. (BTW -for the lurkers - morphology only means form and structure which is what was described in the quote given you - evolutionists like to use big words to confuse the issue for the lurkers and try to sound more knowledgeable than they really are.)
Yes it has. BTW, I was wrong. The modern coelacanth is not even in the same Family as the fossil forms, but only in the same Order. Here is the classsification of the living species (of which there may actually be two, it being presently unclear, as I understand, whether African and Indonesian populations are separate species):
Kingdom: Anamilia
Phylum: Chordata
Class: Osteichthyes (bony fishes)
Order: Coelacanthini
Family: Sarcopterygii
Genus: Latimeria
Species: chalumnae
The following web page will allow you to look side by side at the modern coelacanth and one of the most similar fossil forms. Notice that they are NOT indentical. Look, for instance, as the bones surrounding the eye. The fossil form is also much smaller; 60cm, which is a typical size for fossil coelacanths. The living ones reach 2m. Finally the living coelacanth is viviparous (gives live birth rather than laying eggs) and there is no indication of this in the fossil forms.
Well, gore, the biological species concept (that species are groups of actually or potentially interbreeding natural populations which are reproductively isolated from other such groups) was not formalized until 1942, by Ernst Mayr. Furthermore, Mayr's own historical survey (The Growth of Biological Thought, Harvard Univ Press, 1982, pgs 272-273) lists several "pioneers" who grasped the "essential points" of the biological species concept, but the earliest paper he can cite is from 1896.
Therefore, if we accept your pronouncemnt, gore, we have to assert that every scientist who dealt with the indentification of species prior to the late 19th Century (and certainly prior to Darwin) including the very father of the taxonomic sciences, Linnaeus, and all those other creationists, were not practicing science.
The biological species concept is non-subjective and is therefore valid.
How often do you think scientists actually do tests and observations to adequately confirm the biological species concept fully applies in a particular case? The answer is, almost never (at least in the sense of full confirmation). No species concept is perfect, gore. Again, this does not mean they are not coherent, or useful, or that species don't exist, or can't be imperfectly but usefully indentified.