As Green Mountain Digital’s in-house naturalist/scientist, I spend an awful lot of time naming things… I am forever keeping up with changes in the Latin (otherwise known as scientific) names of various organisms, and trying to determine which common (or English) names are most widely used – birds have standardized English names, but nothing else does (I can think of one mammal, Puma concolor, with at least 8 common names in reasonably wide use).
The genius of Linnaeus’s system of Latin names is that they uniquely identify every species, whether it be animal, plant, fungus or more unusual still. When a new species is found, the name it is assigned fits it in with its closest relatives. While it may seem intimidating, the system is not, in fact, all that difficult to understand. It is based on levels, all nested within one another. Perhaps the easiest way to explain it is to trace us through our family tree…
Kingdom – Anamalia – animals (anything composed of multiple cells that actively seeks food, as opposed to obtaining nutrients from the sun or from decay). This is a huge group, which we share with everything from lobsters to sea anemones, mosquitoes to octopi
Phylum – Chordata (has a notochord or spinal cord) and subphylum Vertebrata (has a backbone) – Everything from fish to fowl, this group contains most things that people immediately think of as “animals” (fish, amphibians, reptiles, birds, mammals). There are a few odd creatures (sea squirts and relatives) that are chordates, but not vertebrates, but, for the most part, you can think of these creatures as things with backbones, most of which have recognizable faces.
Class: Mammalia (nurses its young, has hair – even the apparently hairless whales have a little bit of hair, especially when young). All the mammals from whales to wombats. Many of these creatures are as familiar as dogs or cats, while others are as exotic as anteaters or armadillos, but they’re all clearly more closely related to us than any fish, bird, reptile or amphibian.
Order: Primates (monkeys, apes and people, along with a few more primitive groups like lemurs). These animals all clearly look and act fairly human – they have hands, they tend to live in bands or groups, and most of them communicate in sophisticated ways.
Family: Hominidae (the great apes, including people). Now, we are in the group of our closest relatives – these are all large, highly intelligent, tailless apes that share almost all of their DNA. They all take care of their young for years, while teaching them complex skills they’ll need to know to live in a complex society. Next time you’re at the zoo, watch a gorilla or a chimp, and try to understand their facial expressions and gestures. It’s not hard – their gestures are ours…
Genus Homo (people) and species Homo sapiens (modern humans). No other member of our genus survives, but, from what we know from fossils, our extinct relatives at the genus level were pretty much human.
The levels of names speak directly to levels of evolutionary relatedness. Two organisms that share a genus are more closely related than two that share a family, and so on through the higher levels. For any given species, it shared a common ancestor more recently with other species it shares more of its names with. As an example, the common ancestor of humans and chimpanzees lived about 6 million years ago, while the common ancestor of all mammals probably lived closer to ~100 million years ago.
To avoid a seven-name tongue twister, scientists generally refer to species by the last two levels of their name (if you’re reading this, you’re a member of Homo sapiens). Each genus name is unique throughout life – our genus Homo in the primates is the only genus named Homo allowed to exist anywhere, and because of this, a two-part name uniquely identifies a single species. The higher five levels put the species in context in the evolutionary tree.
The English (or other non-Latin) names are given by people who are not scientists (again, with the exception of birds, where various scientific societies including the American Ornithologists’ Union have standardized names in a variety of languages), and have one advantage, and several disadvantages, compared to the Latin names. The advantage is that the common names may be easier to remember, not being in Latin. The most important disadvantage is that a common name may not always refer to the same thing. Perhaps the worst example is “dolphin”, which refers to a large number of closely related mammals, but also to one fish that has nothing to do with the mammals, and what is called an “elk,” in Europe is a “moose” in North America (despite the fact that there are also “elk” in North America, which are different. Common names are also often not specific (“skunk” and “squirrel” both refer to a range of species) and there are very often multiple common names for the same species, even one language (to say nothing of the range of common names for the same creature in different languages). Because of all of these disadvantages, common names also don’t tell us anything about evolution – a “dolphin” (mammal) is very closely related to a “killer whale”, which is a large dolphin, and only loosely a whale, but neither one is related in any meaningful way to a “dolphin” (fish). There is very little porpoise in trying to sort these critters out by common name (it’s much easier to remember that the dolphinish mammals are all in the same family, the Delphinidae)
Next time, I’ll delve further into how scientific names came to be, the rules for their assignment, and what happens when a bunch of taxonomists (practitioners of the specific branch of science that deals with the naming and classification of living things) get into an intellectual boxing match.