How Biological Classification (Taxonomy) Works

People have always given names to things around them, including plants and animals to identify individuals in the huge world of biodiversity. Essentially, this is what the biological classification of organisms, or Taxonomy, is all about. It is a way for biologists to accurately name and identify one species next to another to better understand the works of ecosystems, evolution and divergence.

This beautiful Naja siamensis, a spitting cobra, belongs to the Elapidae family.

It all started in the 18th century when Carl Linnaeus published a system that would evolve into our system of taxonomic classification for biodiversity. Linnaeus not only gave things a name, but he was the first to develop a hierarchical classification system that held information about what the species was (its Latin name) and who it was closely related to. This would allow scientists to understand complex relations in ecosystems.

We often see fancy Latin names next to the common names on the boards at the zoo that tell us a little about the animal we are looking at. Now, we want to make sure that the next time you see a name like this, you too can understand what is tells us about the animal it was given to!

Bitis rhinoceros, Gaboon Viper – this animal is closely related to the Puff adder, Bitis arietans – in this post you will learn how you can tell by their taxonomic names!

Especially in the reptile hobby, where many animals are often only called by their scientific name, understanding this system will give you a great advantage and fewer terms to look up if you ever read a scientific book or listen to scientists talking!

The hierarchical structure of taxonomic classification

Taxonomy is the practice of identifying and categorizing organisms in a hierarchical structure. Every organism, both living and extinct, is classified in a specific group along with other similar organisms and given a scientific name.

This system has various taxonomic categories. These gradually shift from being very broad an including all kinds of organisms to being more specific until each species eventually has an individual name.

The eight categories are in shrinking order: Domain, Kingdom, Phylum, Class, Order, Family, Genus, and Species.

With each step down this ladder, organisms are split into more and more specific groups.

The taxonomic ladder

For example, the Kingdom “Animalia” is split into many Phyla (plural of Phylum), one of which are the “Chordata” (vertebrates). The Chordata are then split into many Classes, one of which are the “Reptilia” (the reptiles). This means that all Reptilia belong to the Chordata, but the Chordata also include mammals and amphibians and so not everything in the Chordata is necessarily a reptile. This is similar with all the other categories – the closer we get to the species, the narrower the tree of relatives gets!

The broadest category, the “Domain” splits all organisms into three groups. The three Domains of life are the Bacteria, Archaea and Eukaryota.


For a long time, all organisms were classified into just a few Kingdoms like animals, plants, fungi, protists, bacteria and archaea.

However, new genetic analysis of organisms and genetic inheritance models suggest that this division may have to be revised and split into further Kingdoms.


Although a Phylum is still a very broad group, it splits Kingdoms into already very recognized smaller categories. For example, the Kingdom Animalia is split further into the vertebrates (Chordata) or all insects, spiders and crustaceans (Arthropoda). Invertebrates are split into many smaller Phyla.


Classes are the next step closer to the species. Notable classes include the reptiles (Reptilia), mammals and amphibians from the Phylum of vertebrates (Chordata).


Each Class is further separated into Orders. One example from the Reptilia Class are the Squamata. This is a large order of reptiles that collectively includes all scaled reptiles. Orders can be further separated into Sub-Orders. For example, the Serpentes are a Sub-Order of the Squamata and include all snakes.

The Class Reptilia is further separated into Orders and Sub-Orders


A Family is the next level down. Understanding the Families of reptiles can be very helpful to identify a species. One of the most known Family of snakes are the Vipers (Viperidae). Elapids (Elapidae) are also a very notable Family of venomous snakes. Just like Orders, Families can be further separated into Sub-Families. As an example, the Viperidae can be separated into Pit-Vipers (Crotalinae) and Old World Vipers (Viperinae). You can read more on these Families HERE.


The second last step down the classification ladder is the Genus. Genera (plural of Genus) include only very closely related species. All members of a Genus usually have a lot in common and are sometimes only hard to tell apart. One notable genus of snakes are definitely the Rattlesnakes which belong to the Family of the Pit-Vipers (Crotalinae).


The final taxonomic category is the Species. All members of a Species can produce fertile offspring. If this is not the case, the two animals were not from the same species. Each Species is assigned a latin name, often according to one special characteristic or the name of its discoverer. For example, if we look at the largest species of the Genus Crotalus, we realize that it got its Species name (adamanteus = made of diamonds, of adamant) because of the diamond shaped markings on its back! This is of course the well-known Western Diamondback Rattlesnake or Crotalus adamanteus.

How the taxonomic name of an organism comes together

Now, after we have slowly and step by step classified the organism, we have to set its Latin name. This is actually quite simple – as you might have guessed from above, the taxonomic name of an organism is just the name of its Genus and Species put together.

Crotalus adamanteus. The diamond shapes are clearly visible (by Mark Kostich)

So, if we know that the Western Diamondback Rattlesnake is part of the Genus Crotalus and we know that its Species name is adamanteus, then we simply put the two together to get the full taxonomic name: Crotalus adamanteus!

Now you can always understand what the two Latin words on the small boards next to the animals at the Zoo represent and how you can use them to understand how some animals are related!

I hope you have learned something new about Taxonomy today and feel a bit more comfortable with the way organisms are classified in biology!

You are always welcome to leave a comment on my posts or contact me directly via e-mail with your questions!

If you are interested in my sources, just click HERE.

Feel free to continue searching my site for what you would like to know or leave a comment about what you would like to see in the future.




2 Replies to “How Biological Classification (Taxonomy) Works”

  1. Hi, just to tell you I did learn a lot of things here!

    Especially with family and genus, I thought they were the same, or at least it was blurry in my mind.

    I’m a newcomer in the reptile world but I sense that this kind of knowledge will help through my learning,


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