Scientific Terminology: Taxonomy and Nomenclature 101
The origins of medical terms are interesting enough, but Greek and Latin roots are used throughout the sciences, and around here, you'll see them a lot when it comes to species names. There are some interesting ones out there, with some bizarre (and sometimes humorous) meanings...
But first! Some taxonomy basics:
Setting aside phylogeny-specific nomenclature and cladistics for now, Linnaean taxonomy is the system of naming species that has been used since, well, Carl Linnaeus. A "taxon" (plural taxa) is simply a grouping of one or more organisms, judged to belong to the same unit based on any number of qualifications.
Though current "Linnaean taxonomy" (which is what's commonly used in schools and in general literature) differs significantly from Linnaeus' original three-kingdom, five-level, ranked classifications, it's still known by that name and takes many of the concepts from it, such as hierarchical classification. Thanks to the popularity of Linnaeus' 1735 work, Systema Naturae, a solid foundation for modern taxonomy was put in place, with an organized system, and short, understandable, scientific names.
This is a basic schematic demonstrating the hierarchical system that's used when we classify a species:
According to the ICZN, the basic rank is that of species. The next most important rank is that of genus: when an organism is given a species name it is assigned to a genus, and the genus name is part of the species name. Species and genus were both seen by Linnaeus as "God-given"/"natural". Anything above genus was considered a construct made by man to more easily classify the world around him.
The third-most important rank, although it was not used by Linnaeus, is that of family. Even though family is important in understanding the classification of an animal, it is not used in the "scientific name", nor are any of the higher levels in its classification.
So what's a "scientific name?"
The italicized names that you see in scientific literature (and around here) refer to the specific species of a creature, and are called the binomen; that is, "two names". Those two names are the genus (first, and capitalized) and the species (second, never capitalized, even when named after a proper noun). An example of a binomen would be Choloepus hoffmanni - the genus is Choloepus, the two-toed sloths, and the species is Choloepus hoffmanni, Hoffmann's two-toed sloth.
Sometimes there are three names, or the trinomen of a creature. These tell you, first, the genus, second, the species, and third, the subspecies. Take the trinomen Choloepus hoffmanni pallescens. The genus is Choloepus, the species is Choloepus hoffmanni, and the subspecies is Choloepus hoffmanni pallescens, the Peruvian two-toed sloth.
Though you only are told the two (or three) most specific taxonomic groupings for a creature, you can use those (and a phylogenetic tree) to figure out all of the less-specific (Linnaean) taxa it belongs to, such as its Family, Order, Class, and Phylum.
What does the scientific name actually mean, though?
Often, the scientific name describes notable or distinguishing characteristics about a species, that you can decode (scientific terminology time!). Let's take the species Cyclopes didactylus. The first name given tells us that this creature belongs to the genus Cyclopes - "Circle-foot". Within that genus, the species name is Cyclopes didactylus (abbreviated C. didactylus after the first use), and yes, you do repeat the genus name in the species name, by ICZN guidelines. On its own, "didactylus" can be broken down to the roots of di-, dactyl, -(o)us. "Having two fingers." So the binominal can be deciphered as "Circle-foot having two fingers."
Circle-foot two-fingers! (aka the Silky or Pygmy Anteater)
This descriptive-type species name is not the only way scientists assign taxa, though.
For everything above genus, the taxa are fairly regulated/already-determined, are not easy to add and subtract from, and have strict naming guidelines. From genus on down, though, so long as what you've discovered is verified as a new species (or group of species falling together as a genus), congratulations! You have the honor of naming it. Well, assuming it's not patently offensive, vulgar, or unpronounceable. The ICZN approval board or the equivalent for your field has final say on whether or not a species can be given a submitted name.
Still, there are many ways to name a new species. You can name it in reference to physical characteristics, location found, a specific person or group, or even an ironic joke or pun. Look at the name Linnaeus gave the Blue Whale:
Balaenoptera musculis. Balaenoptera = "Baleen-winged", ok, they have huge fins and baleen, so that makes sense. Musculis = "little mouse". Har har har.
"Musculis" can also refer to "muscle," but given that Linnaeus was given to puns and double-meanings, he was well aware of the "little mouse" definition.
**Though the specific epithet for a species can be used in more than one genus, genus names must remain absolutely unique, in accordance with ICZN rules. Ex. Since you can have more than one species with the didactylus epithet, Cyclopes didactylus and Inimicus didactylus are both valid names - though you really don't want to mix up the silky anteater with the "devil stinger"/lumpfish.
**When the specific species is not known, the abbreviation "sp." is used after the genus name. Ex. Lutra sp. refers to either Lutra lutra OR Lutra sumatrana, but it's unknown as to which one. When multiple species within a genus are being referred to (or the specific species is unimportant), the abbreviation "spp." is used after the genus name. Ex. Lutra spp. refers to BOTH Lutra lutra AND Lutra sumatrana.
