TellUs: Taxonomy, the classification of living organisms

Taxonomy: The Classification of Living Organisms

Today I’m discussing an overview of taxonomy, including what it is, providing several examples of how it is used and also how it is universally understood. Although I am not studying a biology degree, this did come up throughout my environmental degree. So there are definitely biologists that will know a lot more than me… but I’ve read up on and researched the best I can in order to provide the best information I can for you!

Taxonomy is the science of classification of living organisms in biology. Modern classification systems are based primarily on grouping organisms with shared physical characteristics, taking into account evolutionary relationships between different groups. For example if it has feathers, then we know it as a bird. Within the ‘bird’ group there are other groups such as eagles, sparrows and parrots. On a higher level, birds can be grouped with mammals, reptiles and amphibians, as they’re all vertebrates (have a backbone) and are of course all animals. 

These different levels can be extended into a hierarchy of classification (shown in the diagram below). I have used the Small White Butterfly as an example organism which is found in Europe, whose caterpillars feed on the cabbage family… So pretty specific!

It isn’t usual for an organism to be described using all classifications shown above but any organism can be precisely defined this way. Each level describes the characteristics in a more precise way, all the way down to the exact species. The usual way to refer to most organisms is to use the genus and species sections, so in this example the butterfly would be referred to as Pieris rapae. The use of Latin is standard practise in taxonomy, for example stating ‘Animalia’ as opposed to ‘animals’. The main reason for this is that the latin is universally accepted, so therefore information can be shared worldwide easily. In addition to this, genus and species names are always italicised, and the genus name always begins with a capital letter and the species name always with a lower case letter. 

It is also worth noting that there are several different systems used in taxonomy. For example in some cases they add an additional higher rank above kingdom, titled domain. However I haven’t learnt this system and the other ones yet and therefore cannot explain them as of now! 

Why is taxonomy important?

Taxonomy is important and used for various different reasons. Firstly it allows researchers, scientists and even ourselves to gain a perspective on the use of species as an indicator of the state of biodiversity. Taking from the butterfly example above, the order, Lepidoptera (butterflies and moths) represents the diversity of all its individual species. The loss of an order, for example all butterflies and moths, would be of more significance to total biodiversity than the loss of a single species belonging to it. In addition to the direct loss of all the species in the order, the removal of this unique group would have a major impact on the stability of the many habitats and ecosystems in which they play a key role, as pollinators of plants and a food resource to other animals. 

As a result of taxonomy it also allows organisations and scientists etc to make decisions on what species or group of species are threatened with extinction. The list for this goes from ‘critically endangered’ (some flagged as being possibly extinct) decreasing to ‘endangered’ and then ‘vulnerable’. Each term is described by a strict criteria taking into account biological factors such as: rate of decline, population size and distribution and the area of geographic distribution or range.