Zoologic taxonomy, originally conceived by Linnaeus, is now the product of a 271 year biology team. Their lengthy expertise has built perhaps our most elegant organizational structure, one that expands as biologic knowledge grows. This expansion sometimes requires new categories. We are a highly diverse planet and the taxonomic structure for one group of animals may not fit the biologic details of another group. There are even competing theories on the organizational structure for life on earth. We’ll look at those in future postings.
In the meantime, I want to explicate the structural strategy for “Snoopy in Subphylum Vertebrata.” That table displays taxonomic categories for 24 animals in the imagination of my former client Snoopy. None are classified into all 15 available categories, which causes a display discrepancy right there in the first two Classes. The only Class in this collection with a Superclass parent is the ray-finned fish. The next Class is birds. Displaying the Classes in alphabetic hierarchy turns a bird into a bony fish.
Superclass Osteichthyes (bony fish)
Class Actinopterygii (ray-finned fish)
Class Aves (bird)
Zoology Websites resolve this by listing all of an animal’s categories in a drilldown. At the Species level, only the hierarchy for that animal is fully displayed. My goal, however, is to chart the taxonomy of Snoopy’s imagination on one page. A list of every category for each species takes 255 lines.
The animals in this group are all vertebrates. So I save 72 lines by moving the top three categories to the structure’s title, “Snoopy in Subphylum Vertebrata: Phylum Chordata of the Animal Kingdom.” Class is the highest differentiating category that includes the entire group. Similar animals are placed together by organizing the structure in alphabetic order by Class, indicated by all caps. The list is now 183 lines.
Because it does not repeat classifications, an indented hierarchy shortens the list to 113 lines, but then we are back to the problem of birds and bony fish. One solution builds a vertical hierarchy displaying each of an animal’s categories in a set of columns. Here’s a portion of a horizontal hierarchy for the shark in a beagle’s imagination. It can only be the porbeagle shark.
(guitarfish, ray, shark)
(guitarfish, ray, shark)
(great white & mackerel shark)
(mackerel & porbeagle shark)
This gives 24 rows instead of 113, but it also has 12 columns, which is too wide for Bloglines.
The names of categories in this table are based on the original Linnaean categories of Class, Order, Family, Genus, and Species. Snoopy’s animals are all classified into each of these. The auxiliary categories vary by animal but each is associated with one of the big five. In the “Snoopy in Subphylum Vertebrata” table, Superclass and Superorder are parent categories of Class and Order. Children are Subclass, Infraclass, Suborder, Infraorder, and Subfamily. There are five columns for the major categories, with auxiliary categories entered into associated columns. Excepting Genus and Species, which do not have auxiliary categories in this structure, including the category name with the animal’s name clarifies the hierarchic relationship. The first three categories for placental mammals and the first mammalian Order in Snoopy’s group are displayed in this vertical and horizontal hierarchy.
|Class MAMMALIA (mammal)|
|Subclass Theria (live-birth mammal)|
|Infraclass Eutheria (placental mammal)||Order Artiodactyla (cloven-hoofed ungulate)|
Listing every category for each animal, from Superclass to Species, builds a table with 82 rows and lots of repetition. Of the 24 species, 14 are placental mammals. Hierarchic indentation removes repetition and shortens the table to 46 rows. The resulting structure is at once vertical, horizontal and indented. Each row is a horizontal hierarchy. Columns contain both equal classifications and a vertical hierarchy. Here’s a portion of the Aves structure.
|Class AVES (bird)||Order Ciconiiformes (eagle, heron, stork)||Family Accipitridae (eagle, hawk)|
|Family Ciconiidae (American vulture)|
|Family Pelecanidae (pelican)|
|Family Spheniscidae (penguin)|
|Order Strigiformes (owl)||Family Strigidae (typical owl)|
|Subfamily Striginae (typical owl)|
Eagles, vultures, pelicans, and penguins are all children of Ciconiiformes at the Family level, but Striginae is Subfamily only to Strigidae. Multiple children of a parent category are presented as vertical and indented hierarchies. Aves are a vertical parent of Ciconiiformes and an indented parent to Strigiformes. For clarity, I put a space between the two Orders in this sample. The full table has a space between each species. The resulting structure offers a logical glimpse into Snoopy’s imagination, where bony fish swim and birds fly, except for penguins.
|Superclass Osteichthyes (bony fish)|
|Class ACTINOPTERYGII (ray-finned fish)|
|Subclass Neopterygii (neopterygian fish)|
|Infraclass Teleostei (teleost fish)||Superorder Ostariophysi (catfish, minnow, piranha)|
|Order Characiformes (leporin, piranha)|
|Class AVES (bird)||Order Ciconiiformes (eagle, heron, stork)|