Paul Solberg #fundie

Paul Solberg #fundie forums.carm.org

[On taxonomic classification]

Well I just feel like being the Taxonimist's adversary here: As I said above. So many critters have eyes, but we don't lump them on that basis. Many critters have ears and we don't lump them on that basis either. I could go on, but I'm sure you already got the point. Why should mammals be a whole different category than non mammals. One thing that comes to mind is the dolphin. It is a mammal, but it is a fish. This brings up the question: Why is the dolphin put in the same category as people? I think this reflects evolutionary thinking. But I could be wrong.

89 comments

old comment by Javascap

Dolphin:

Kingdom: Animalia - Animal
Phylum: Chordata - Has a spine
Class: Mammalia - Maintains own body heat
Order: Cetacea - Whales, dolphins, or porpoises.
Family: Delphinidae - Dolphins, specifically
Genus: Delphinus - All variations of the common dolphin.
Species: Here would go the Latin name for the specific animal.

Human:

Kingdom: Animalia - Animal
Phylum: Chordata - Has a spine
Class: Mammalia - Maintains own heat
Order: Primates - ancestors that lived in the trees of tropical forests
Family: Hominidae - Great Apes, like the Chimp or Gorilla or orangutans
Genus: Homo - Modern humans and close (extinct) species
Species: H. sapiens - The actual specie

There is the difference.

old comment by John-in-Oz

I have no problem with this.
I too am greatly ignorant; it is a fixable fault. The acknowledgement 'I could be wrong' destroys its claim to Fundiness.
The only thing thst stops this being a perfect example of intellectual integrity is the absence of "so I'll go look it up".
So I did, and he's right. A taxonomy can be constructed on any principle, including classification by presence of eyes. It could even be by alphabetical order.
The system we use is a supertype/subtype relationship. It does give an appearence of evolution even in circumstances where evolution clearly does not apply, for example vehicles/cars.
Classifying a dolphin as a mammal and a shark as a fish is now so familiar to most of us that we forget how surprised we were to first learn of it, or how unobvious the differences really are.
It's not so much in the method of classification that taxonomy supports evolution, as in the difficuties of classification. Can anybody tell me the name of the fundies and the particular fossil, whereby two fundies ahree there's no intermediate fossils, but one says "that's clearly an ape" while the other says "that's clearly a human being"?

old comment by Professor M

@ John-in-Oz --

The current trend (which involves a number of reclassifications) is to adjust taxonomy as needed to reflect evolutionary realities. There are a few generally-accepted deviations from this plan (accepting paraphyletic groups -- the common ancestor of all reptiles is also an ancestor of birds, meaning that the "proper" taxonomic grouping would be "non-mammalian amniotes" including both birds and reptiles), but for the most part the initial Linnaean taxonomy was actually fairly close to evolutionary history in the broad strokes. The only rigorously systematic taxonomy is to develop a continually-updated best-estimate model of common descent as the basis for taxonomic distinctions. Any other approach leads to biology becoming an unpracticable collection of random data.

old comment by dionysus

It's not as simple as "these all have eyes" or "these all have ears". Rather, there is a nested hierarchy of features that are present in all living creatures past and present. Sure, dogs and bees both have eyes but their eyes are incredibly different. Meanwhile, a human's eyes and a chimps eyes are incredibly similar. What we see even in a feature like eyes is branching patter, not just physically but genetically. In fact, fish with eyes and eyeless fish are closely related even though one has eyes and one lacks them, but their genetics and the structure of their now eyeless heads are very similar.

But let's not use an evolutionary example, let's use something like a car. Now, you can have a blue sports car with a spoiler and a plane. By your ridiculous assertion we should be lumping them together since spoilers kind of look like the tail on some planes. But, a more thorough look at the history and structure will tell you that those two parts actually had a different origin. However, this same look through the history and structure will tell you that the plane was developed based on other, older plane designs and the car was developed from older cars. Granted, using inanimate objects makes this comparison highly imperfect as there can be as much cross-pollination as the designers want. Which is, coincidentally, something that doesn't help the designer argument as we don't have an chimeras as would be expected, rather, it turns out that similar looking parts on unrelated creatures took DIFFERENT ways to get there and inexplicably have different structures. For example, a bird wing and a dragonfly wings are enormously different and involve completely different structures and base body parts, even though they do the exact same thing. Whereas designed things (like cars and other modes of transportation) will use the same design almost ENTIRELY for things like radios, transmissions, fuel tanks without much variation despite different styles and manufacturers. Arbitrarily using different strategies (some FAR less efficient) isn't something a good designer would do.

old comment by The_L

Hey dumbass, fish have gills and scales, lay shell-less eggs, are cold-blooded, have a two-chambered heart, and do not produce milk. These are requirements for an animal to be a fish.

Dolphins have lungs, give birth to live offspring, have no scales, are warm-blooded, have a four-chambered heart, and produce milk. All of these are mammalian traits.

If "fish" just meant "animals that live in the water," then invertebrates such as crabs*, shrimp*, oysters**, sea slugs**, octopi**, jellyfish***, sea stars****, sea urchins****, and sea squirts***** would all be counted as fish, as well, despite not looking anything like a fish. So would sponges, because despite not being mobile, sponges are actually animals as well.

*Phylum Arthropoda
**Phylum Mollusca
***Phylum Cnidaria
****Phylum Echinodermata
*****Actually in the phylum Cordata, just like fish and mammals, but do not have backbones like most chordates.

old comment by John

So many critters have eyes, but we don't lump them on that basis.

Actually, we could. But we find that everything that has an eye has junctions between their cells that allow the cells to communicate with each other. But not everything that has junctions between their cells that allow the cells to communicate with each other has an eye. So we don't use eyes as a classification criterion.

We start by separating animals into those that have junctions between their cells that allow the cells to communicate with each other and those that don't. At this point, we could separate them into animals with eyes and animals without eyes. But we'd find the animals in each group would have almost nothing else in common with each other. At this point, no further classification hierarchy is possible.

Here's an analogy: all computers use electricity, but not everything that uses electricity is a computer. So we might begin by splitting off "things that use electricity". At this point, we could separate the remainder into things that are blue or not blue. But that would be arbitrary and useless, because blue electrical things have nothing else in common other than their color. What next classification could you use that would be uniquely contained in the category "blue electrical appliances" (i.e., would apply only to blue electrical appliances and not to appliances of any other color)?

Paul Solberg #fundie forums.carm.org

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