lpetrich

Unlike their pre-Darwinian predecessors, present-day creationists generally accept the evolution of new species. But they claim that they can recognize "created kinds", which are groups of species that share specially-created ancestors. However, they have been short on strategies for recognizing "created kinds", or "baramin", as they sometimes call them. They sometimes claim that a "created kind" is approximately a Linnean family or order, though without any reasons for doing so.

Our favorite wildlife biologist Ed has stated that a "created kind" is approximately equivalent to a Linnean family, though he has yet to state any reason why that might be the case.

But now for the question of what meaning a Linnean family might have. I first discuss two different approaches to taxonomy.

Cladistics was first developed by German entomologist Willi Hennig in the 1950's; it is rigorously based on an understanding of evolution. In it, the only legitimate groupings are of an ancestor and all of its descendants, which may be recognized with their shared and derived features. Features also present in ancestors do not count for determining relationships.

Cladistics has a rather formidable jargon. A group with an ancestor and all its descendants is "monophyletic", a group with more than one ancestor is "polyphyletic", and a group without some of its descendants is "paraphyletic". Features that are shared and present in ancestors are "symplesiomorphic", features that are shared in a group but not present in the group's ancestors are "synapomorphic". Features that are the result of convergence are "homoplasic".

Although it has provoked some controversy over the years, it is now accepted as a rigorous approach to classification. It is even possible to test the validity of cladistic classifications, by seeing if some proposed classification has an unreasonable amount of convergence.

A rival approach, phenetics, classifies by degree of resemblance. One early pioneer of that approach was 18th-cy. French biologist Michel Adanson, who proposed classifying plants by degree of resemblance. This approach has become more practical with the use of computers; computers have also made it easy to generate and test cladistics hypotheses.

Traditional classification was first codified by 18th-cy. biologist Karl von Linne', Latinized to Carolus Linnaeus. He proposed a hierarchy of groupings: kingdom, phylum, class, order, family, genus, and species -- groupings which have usually been constructed with some rather subjective hybrid of cladistic and phenetic techniques. Also very subjective is where a group fits in the Linnean hyerarchy -- is it a genus or a family or an order? Or a class or a phylum or a kingdom? A further problem is that it does not provide enough levels for grouping in many cases; this has led to the invention of numerous intermediate levels.

Some biologists have proposed an objective version of the Linnean hierarchy, in which each level corresponds to a time of divergence. And others have even proposed disposing of it.

This means that trying to identify "created kinds" with Linnean families or orders is trying to identify them with a level of grouping that is determined very subjectively.

Let's consider the "dog family". What might it include?

Domestic dogs? (either Canis familiaris or Canis lupus familiaris; with the latter classification, the gray wolf becomes Canis lupus lycaon)

Dogs, wolves, coyotes, and jackals? (genus Canis)

Including various fox species and the like? (family Canidae)

Including bears, raccoons, weasels, otters, pinnipeds, and the like? (superfamily Canoidea)

The "cat family" has a similar ambiguity:

Domestic cats? (either Felis catus or Felis sylvestris catus)

Including closely-related small cats? (genus Felis)

Including various other cats, usually big ones: lions, tigers, lynxes, cougars, ocelots, etc.? (family Felidae)

Including hyenas, civets, and mongooses? (superfamily Feloidea)

I note in passing that most of the Felidae had often been put in the genus Felis -- including many of the big cats! However, most other felines -- and all the big cats -- are now put in separate genera, like Panthera for the lion, tiger, and leopard, Puma for the cougar (mountain lion, puma, ...), etc.

[ May 22, 2002: Message edited by: lpetrich ]

(Corrected a typo)

[ May 23, 2002: Message edited by: lpetrich ]</p>

Dr.GH

A good summery lpetrich.

Some related web page sources :

<a href="http://ucsu.colorado.edu/~theobal/PE.html" target="_blank">Mostly about P.E.</a>

<a href="http://www.aaas.org/spp/dser/evolution/science/mayr.htm" target="_blank">What is a species anyway?</a>

<a href="http://asa.calvin.edu/ASA/resources/Miller.html" target="_blank">And general tanonomy.</a>

Quetzal

lp: Excellent summation. Another aspect of common creationist fallacy related to taxonomy is their continual insistence that the nomenclature used by biology and paleontology somehow indicates that there is an unbreachable physical barrier between species based solely on their classification. I find this incredibly odd.

As you noted, biologists, paleontologists and their ilk classify life based on species, genus, etc. What the creationists continually miss is that these classifications - especially under cladistics - merely show the relatedness of groups of organisms. It isn't some intrinsic property of a population. What they apparently get so confused about (although it wouldn't be confusing if they thought about it), is that all these different hierarchies are simply larger groups of species. A genus is a bunch of species that are really closely related - sharing some traits, being different in others. Familes are a group of genera, etc. All these categories are simply names given to ever-larger groupings of related species - nothing more. IOW, any mechanisms (say, natural selection or genetic drift) working at the individual or population/species level will axiomatically operate in identical fashion at the level of a class or even phylum, etc. Why? Because a phylum is simply a very large grouping of species that share some common trait (such as a spinal cord). So when scientists talk about transitions between, say, orders, especially within the fossil record, they're saying they've found a species that shares traits across order boundaries. In short, they're merely describing the relative closeness of members of two species.

There isn't some mystical barrier based on taxonomic nomenclature. It's just two different species - more or less related - and ultimately identical to comparisons between two living species of hare (say, between Lepus arctus and Lepus townseii) or between a domestic cat and wildcat you noted above.

I think this misunderstanding will doom the entire "baraminology" attempt to ultimate failure. They're trying to force-fit organisms into a classification scheme without understanding what classification is all about.

Oolon Colluphid

It should also be noted that even with modern organisms, it can be very difficult to decide which taxon (any taxon, pick a taxon) some things belong in. Among snakes, cobras are put in their own family (Elapidae), but the distinguishing features of them are found to a greater or lesser extent in many other groups. Malagasay mongooses also fall between the two families -- the mongooses, and the civets and genets (will try to add specifics shortly, it’s to do with presence of ‘civet’ glands iirc), and fossas are similarly problematic.

[Edited: further info in post below]

And when we get to fossils, it (naturally, from the evolution perspective) gets even more complicated. Seymouria cannot be definitively be called an amphibian or reptile; witness the problems creationists have deciding whether Homo habilis is ‘ape’ or ‘human’; Archaeopteryx is so similar in its skeleton to some dromeosaurs that some specimens were originally classified as dinosaur; is Procynosuchus a reptile or mammal?

Some points for the creationists to ponder.

And to add to what Morpho said... Isn’t it amazing how often people like Ed use the fact that there’s two principal hominid genera (ignoring Paranthropus ) -- one, called [i]Australopithecus[I], literally meaning ‘southern ape’, and the other, Homo, meaning ‘man’ -- to justify a distinction between the two: “one’s ape, the other’s human” .

TTFN, Oolon

[ May 23, 2002: Message edited by: Oolon Colluphid ]</p>

Quetzal

Oolon: Yep. I guess for cretinists, the "name of the thing IS the thing". Can you say, "magical thinking?" After all, isn't that the basis for sympathetic magic?

lpetrich

And the Paranthropus species have often been classified as inside Australopithecus -- it may depend on how different the classifier considers the Paranthropus species from the likes of Australopithecus africanus, and thus whether they are worthy of a separate genus.

Traditional and cladistic approaches to classification have had some interesting conflicts; the traditional approach has admitted several groups that are invalid under cladistic criteria -- most likely for phenetic reasons.

Thus, Pinnipedia has been demoted from an order in Mammalia to a subtaxon of Canoidea in Carnivora (the <a href="http://www.tolweb.org" target="_blank">Tree of Life</a> pages promote Canoidea and Feloidea to suborders Caniformes and Feliformes to accommodate a pinniped superfamily).

Also, Cetacea has been turned into a suborder of Artiodactyla in some recent classifications, with Artiodactyla being renamed Cetartiodactyla.

And, of course, Aves being well-defined cladistically and Reptilia not being.

lpetrich

Also, there have been some big revisions in taxonomy in recent decades, as molecular techniques have become more widely accessible and used.

Thus, we have seen:

Cetacea moved inside of Artiodactyla

The ~20 eutherian orders resolved from a "lawn" into a few groups, like Afrotheria.

Recognition of Ecdysozoa inside of Protostomia in the animal kingdom.

A major revision of angiosperm taxonomy, into a few lineages of primitive dicots, the monocots, and the eudicots -- with the latter also being heavily revised.

A revolution in prokaryote taxonomy.

There are hints of more big revisions to come, such as in arthropods (insects being descended from certain crustaceans) and in protists (not very well sampled).

Coragyps

It never fails to amuse me that Linneaus (a creationist, you know ) classified the only great ape he knew about, the chimpanzee, as Homo troglodytes. He moved chimps to Pan , I think, but one has to wonder what made him change his mind?

Peez

That is interesting. Would you have a reference, as I might want to bring this up (from time to time).

Peez

Oolon Colluphid

Malagasay mongoose info as promised:

Civets and genets are family Viverridae, with 35 species in 20 genera. Mongooses are family Herpestidae, and there's 35 species in 17 genera. Now, there are a number of peculiarities that distinguish the groups. The coat of civets and genets is generally striped or spotted; the ear flaps have pockets (bursae) on the lateral margins, and most have perineal (civet) glands near the genitals. But although true mongooses (subfamily Herpestinae) are uniformly coloured, lack ear bursae and the perineal gland, Malagasay mongooses (subfamily Galidiinae) do have ear bursae, some have perineal glands, and three of the four species are variously striped.

And some questions for creationists, such as Ed, who think Family equates to 'kind':

'Dog' kind and cat kind... fair enough. But there's more to life than just mammals... and even among them, you have potential problems...

Are the 18 families in the order Chiroptera not all of the 'bat' kind?

Are dolphins (family Delphinidae - 36 species, 17 genera) so different from porpoises (family Phocoenidae) and river dolphins (four separate families Lipotidae, Iniidae, Platonistidae and Pontoporiidae) that they are separate kinds? (Many river dolphins, btw, have greatly reduced, ie near-functionless eyes.)

Are the Right whales (family Balaenidae, eg Bowhead and Northern Right whales) really that different from the Rorquals (family Balaenopteridae, eg Minke, Blue and Humpback whales)? Wilson and Reeder 1993 listed 41 different families in the order Cetacea.

But if you move a level up, to Order, you'll have to accept dogs, cats, bears, hyaenas, etc etc (order Carnivora) as part of the same kind.

Would Ed and co care to explain why the two Echidna species (family Tachyglossidae) are not of the same kind as the Platypus (family Ornithorhynchidae) despite both being the only egg laying mammals, and numerous other features in common, eg a poisonous spur on the rear legs? (Wanna explain, while you're at it, why the Echidnas have such a spur, but it being degenerate -- not functional?) Should Echidnas not be in the porcupine kind? Or the anteater kind? Shouldn't the platypus be in the duck kind?!

Cheers, Oolon