Scientific Nomenclature, or How Biological Organisms Are Named

Hopefully you’ve already looked over my page about taxonomy and have an idea of how biological organisms are classified.  (If not, it might be helpful to take a look at that before reading further.)  This page covers how biological organisms are named and what you can learn about organisms based on the scientific words that are associated with them.

Because I’m an entomologist, I usually only think of things that belong to the class Hexapoda (Kingdom Animalia, Phylum Arthropoda), or the organisms with exoskeletons, six legs, and three body segments.  In fact, we don’t even think about the class so much, but the orders are very important.  If you’ve ever had to make an insect collection for a class, you know that there are lots of different insect orders.  Insect orders encompass broad groups of organisms.  For example, the beetles, Order Coleoptera, includes more known species than all the other non-insect animals combined!  The order names within Animalia do not have any specific guidelines beyond having a capital letter at the beginning of the word, but if you know Latin, Greek, or your root words you will notice that their names are often very descriptive.  (The names of groups at other levels of classification are also often descriptive in this way.)  The suffix -ptera refers to wings.  Coleop- refers to sheaths.  Thus, the word Coleoptera means sheathed wings.  This describes their hardened outer wings, or elytra, that cover and protect the membranous flying wings underneath.

Family names have a few more guidelines.  Animal families end with the suffix -idae and start with a capital letter.  Let’s look at the name for the group I work with, the Belostomatidae.  You can tell this is a family, and not any other level of classification, because it has the suffix -idae at the end of the word and starts with a capital B.  This is complicated a little when scientists shorten the word to make reference to all of the members of the group in more casual conversation.  For example, it’s easier to say “belostomatids” than “insects belonging to the family Belostomatidae.”  When we shorten a family name, the capital letter comes off, along with some of the letters are the end of the word.  In my blog, I will be referring to things by these shortened family names (orders too!), so now you’ll know why I do that and what it signifies.

All described species of biological organisms have a two word name associated with them.  For example, one of the species of water bugs I work on is named Abedus herberti.  If you recall from the page on taxonomy, the first word is the genus and the second is the specific species within the genus.  All genera and species names are italicized when we write about them, so if you ever see a name of an organism in italics, you know you’re looking at either a genus or a species.  You can tell whether it is a genus or species by looking at the capital letters in the word.  The genus name is always capitalized, but the species name is not.

Sometimes scientists will shorten the scientific names of species to make them easier to talk and write about.  There are rules about how this works that are more or less well accepted.  The first time you write or talk about a species, you are supposed to use the full name.  If I wanted to talk about that water bug for the first time during a presentation, I would need to use the full name, Abedus herberti.  The second time I mentioned it, I could shorten it to A. herberti. By this point, you’ve already heard the full name, so there’s no need to mention the genus name again.  In printed publications, it’s standard practice to include the full name in each section of a document so that readers are reminded of exactly what organism you’re referring to, in case they’ve forgotten.

So, the next time you see me write the word odonate, you’ll know I’m talking about a member of the order Odonata (the dragonflies and damselflies).  If I use the word belostomatid, you’ll know I’m talking about a member of the family Belostomatidae.  It all makes sense once you’ve played around a little with the words and have an idea of what they mean, so keep reading and it will become easier!


Text copyright © 2009


4 thoughts on “Scientific Nomenclature, or How Biological Organisms Are Named

  1. Stumbled on to your web site. Very nice. I have been collecting “bugs” for 50 years, and learned some things today. Do you have a collection? What’s your favorite order? I live in Central America (Panama) and get to see lots of bugs. Thanks,

    • Hello! Glad to hear that you learned something new – that’s what I strive for! And yes, I do have a collection. I’ve been collecting since I was about 12 years old, though I don’t really go on many collecting trips anymore outside of my work with aquatic insects, so my collection isn’t gigantic, about 8 drawers total and probably 500 vials. My favorite orders are the Odonata followed closely by the Megaloptera (if you still consider them separate from Neuroptera) and Hemiptera. Honestly though, I like all aquatic insects, regardless of which orders they belong to. Dragonflies, hellgrammites, giant water bugs, and water scorpions are my absolute favorites! How about you?

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