How & Why We Classify Organisms

Humans in general feel a need to create order by organizing things in their environment – hands up those who keep their t-shirts and jeans in separate drawers, or arrange them in order of most recently worn or by colour! 

With the universal desire for order, comes a related compulsion to  name things. The great Chinese thinker and philosopher K’ung Fu Tzu (better known by his Latin name, Confucius) is widely credited as the source of the old Chinese proverb: “The beginning of wisdom is to call things by their proper name.” 

But, what’s the point of naming things? Why do we bother?

What is taxonomy?

Living things are all around us. You know that humans and animals are living, but what about the trees in the forest or even the microscopic organisms in a pond? Even though they appear to be very different from one another, they are all living things as well.

Taxonomy is a science that deals with naming, describing and classifying all living organisms including plants. 

Why do we name things?

We name objects because it makes our lives easier. Let’s say you’re sitting on the sofa and you want your friend to pass the remote so you can see what else is on the TV – this process is rather difficult without names. 

A request like, “Please pass the thing on the thingy. I want to see what’s on the ‘thing’,” is likely to be met with confusion. The request is easier for the other person to follow if things have names: “Please pass the remote that’s on the coffee table. I want to see what’s on the TV”.

So, the act of naming facilitates communication, whether the objects are furniture, machinery, or animals. We, for example, call a ‘fish’ with a cartilaginous skeleton and between five and seven pairs of gills a “shark”. This allows us to tell another person what animal we’re looking at or talking about. 

Why do we classify organisms in groups?

The use of a name certainly helps, but is not without problems. Telling someone that you saw sharks while on holiday can be like saying you had vegetables for dinner; it’s not quite as specific as we might want. 

After all, there are lots of different ‘types’ of vegetables (and sharks). So, to make our meaning as clear as possible, organisms (be they animals, plants, bacteria) are split into narrow groups and each group is given a name.

For example, the group of ‘fish’ we call sharks is further subdivided into different types of sharks based largely on how they look, both internally (i.e. their skeleton, internal organs etc.) and externally (i.e. fins, gills, skin, colour etc.). 

Large groups are then split into smaller, more specific ones and so on down the line until you have a group containing all the animals considered to be exactly the same in terms of the features.

This is the species level of classification. Humans, chimpanzees, great white sharks, blackbirds and red squirrels are all examples of species.

Why do we need a scientific name?

This system of giving each species a name is all well and good and it certainly makes it easier to be precise in our communications. But, in order for the system to work, everyone must call that “something” by the same universally agreed name. If the process isn’t regulated we can run into problems. 

The problem gets even more complicated when local names, different languages and different dialects are considered and one animal may have different names in different languages. 

So, how do we get around this problem? Well, we do it by giving most species known to science two names: a vernacular (common) and a scientific (often referred to as Latin, but more accurately a Latinized-Greek) one. While it’s true that not all species have a vernacular name (e.g. many bacteria, mosses, lichens etc.), this isn’t a major issue because it is the Latin name that’s the important one; it’s designed to remove confusion caused by many names.

Scientific names follow a specific set of rules. Scientists use a two-name system called a Binomial Naming System. Scientists name animals and plants using the system that describes the genus and species of the organism. The first word is the genus and the second is the species.

Let’s take a brief look at how we arrived at the classification system we use today.

Birth of the binomen

Carolus Linnaeus, also known as the “Father of Taxonomy”, is largely responsible for the way we classify creatures today.

Linnaeus was born in Sweden in May 1707. In 1735, he published the first edition of his classification of living things, titled Systema Naturae. In this work he listed all types of animals that he knew of. 

Not only did Linnaeus list all the animals he knew about; he also grouped them by his own hierarchical scheme according to how closely related he thought they were, which he based on how similar they looked to one another. Linnaeus’ scheme has proven to be robust and much of it remains to this day.

In Linnaeus’ original work, objects were grouped into one of three Kingdoms: Animalia (animals); Vegetabilia (plants); or Mineralia (minerals) – hence the familiar “animal, vegetable or mineral” options. 

As our knowledge of the natural world grew, scientists found that these three kingdoms weren’t enough to do justice to the enormous diversity of life on Earth.

We now recognize six kingdoms: 

Conclusion

So, before we finish this fascinating read, let’s revise why classification is important. It is necessary to classify organisms because:

1. Classification allows us to understand diversity better.
2. It helps in the identification of living organisms as well as in understanding the diversity of living organisms.
3. Classification helps us to learn about different kinds of plants and animals, their features, similarities and differences.
4. It enables us to understand how complex organisms evolve from simpler organisms.
5. To understand and study the features, similarities and differences between different living organisms, they are grouped under different categories.
6. Classification is a tool which helps us to deal with a great diversity of living forms.
7. It is essential to understand the inter-relationships among the different groups of organisms.
8. Classification forms a base for the development of other biological sciences.