Defining biological taxa with GURPS

[RyanW]

Originally Posted by Anthony

Unfortunately, biological taxa are (mostly*) not defined by structural similarities, they're defined by evolutionary links. Thus, you can wind up with very similar creatures that are a long distanced apart by taxonomy.

*the exception is reptiles, which should properly either be split or include birds.

Don't forget fish, which really should include all vertebrates. Trout are more closely related to camels than to sharks.

[Anthony]

Note that either Aristotelian or Linnaean taxonomy would allow aliens to be in the same taxa as terrestrial life.

[Michael Thayne]

Originally Posted by whswhs

Insistence, maybe. But the project of classifying according to common ancestry emerged fairly directly from Darwin's work, and Ernst Haeckel was working along those lines by the late 19th century.

But I'm not actually commenting or you (stated or inferred) methodology. I'm making a comment purely on the stylistic impression your list of taxa gives me: in beteeen Linnaeus's classes of Mammalia, Aves, Amphibia, Pisces, Insects, and Vermes, and Cuvier's embranchements of Vertebrata, Mollusca, Articulata, and Radiata. Nothing like even Haeckel, let alone the bio texts of the sixties or the sometimes radical reshuffling emerging from cladistics and gene sequencing.

All of the latter were products of evolutionary thinking; the former were not and I doubt they can be made compatible with it, which it sounds as if you would like to do.

I didn't mean the list to be complete, hence the ??? at the end. That was there because I was too lazy to try to come up with a complete list of invertebrate taxa with members weighing more than 1 lb. So for example, when I said "mollusks" I really meant "mollusks" (which are probably monophyletic?), not some broader category from earlier systems of taxonomy.

But maybe it would be better to drop "fish" and "reptiles" from my taxonomy. From a GURPS point of view, "tetrapod" is actually a very useful concept - it means the total number of arms, legs, and wings can't exceed four, not counting any mouths / tails / noses dexterous enough to count as "manipulators" for GURPS purposes. One of the few things I liked about James Cameron's Avatar movie is that it game the animals of the alien planet a genuinely alien feel by violating this rule over and over again. OTOH I'm not sure what the interesting differences are in GURPS terms between jawless fish, cartilaginous fishes, and bony fish.

[Pursuivant]

If you're trying to do morphology templates for aliens it's probably a better idea to think in terms of ecological niches rather than Terran clades.

Take a look at GURPS Space for "generic" ecological niches.

If you want to dig into GURPS 3E, try to find a copy of GURPS Uplift.

For fan-made resources, Luke Campbell's Animalia is a very good jumping-off point.

There are also a number of different animal templates Chudley's GURPS T.M.N.T. site

T. Bone's GURPS Diner GULLIVER rules also include lots of info about designing non-human critters.

[Michael Thayne]

Originally Posted by Pursuivant

If you're trying to do morphology templates for aliens it's probably a better idea to think in terms of ecological niches rather than Terran clades.

Take a look at GURPS Space for "generic" ecological niches.

I'm not suggesting using terran clades for aliens. Rather, I'm thinking about using it as a jumping-off point for thinking about what clades an alien planet might have, e.g. a planet with hexapods rather than tetrapods could have what Template Toolkit 2 calls "angeloids" and "centauroids".

If you want to dig into GURPS 3E, try to find a copy of GURPS Uplift.

For fan-made resources, Luke Campbell's Animalia is a very good jumping-off point.

There are also a number of different animal templates Chudley's GURPS T.M.N.T. site

T. Bone's GURPS Diner GULLIVER rules also include lots of info about designing non-human critters.

Thanks, I'll take a look at these suggestions. I may actually have a hardcopy of GURPS Uplift lying around somewhere.

[whswhs]

Originally Posted by Michael Thayne

I didn't mean the list to be complete, hence the ??? at the end. That was there because I was too lazy to try to come up with a complete list of invertebrate taxa with members weighing more than 1 lb.

In terms of GURPS mechanics, you can approximate weight as the cube of (HP/2). So HP 1 (and ST 1 for a typical animal) actually is closer to 1/8 lb. or 2 oz.

But while in GURPS terms looking only at big animals makes sense, if you delete all the smaller ones from the evolutionary record what remains won't make a lot of sense. Too many gaps! I would want to synthesize the whole phylogenetic tree, including the tiny ones, even if I was only going to do templates for the larger fraction.

[tbone]

Originally Posted by Michael Thayne

. . . otherwise they're going to be too small to even rate ST 1 in GURPS terms

Is that necessarily a problem? Every ST score can be assumed to be rounded up or down from an infinite range of continuous, fractional scores. For teeny worms and what not, you could make a note that the creatures actually have some tiny little fraction of a point of ST, but it's treated as 0 for game purposes.