At first I thought it was clear: life, domain, realm, phylum, class, order, family, genus, and species. But then I saw that between domain and empire there was supergroup. And there are also different rankings, so which one is used? If you type in a name of a species, you can always see the taxonomy on wikipedia and it’s always the same, I think, so which one is that?
It is certainly the intention to have a universal classification of species, but such a classification remains artificial, ie invented by man. And scientists don’t always agree, or at least not on all the details. Some scientists find new research results and propose a certain adjustment of the system on the basis of this. Therefore, different classification systems may exist. In the longer term, an agreement is usually found that most agree with, which then approaches a universal system. And you can find that on websites like Wikipedia.
The method of classification also changes over time. In the past, anatomical similarities were mainly used as a basis for collecting species in a group. Now people are increasingly using DNA and protein analyzes that are compared.
Modern classification no longer only looks at common features, but mainly at derived features. That is the basis of the method called “cladistics”: organisms are placed in a clade (= group) when they have a common ancestor and no organisms outside the clade have the same ancestor. Thus, the organisms within one clade have unique, common derived characteristics (derived from that last common ancestor).
This can also be applied to extinct species if DNA or protein can be obtained from fossil bones, e.g. For example, birds show more similarities with dinosaurs than with any other animal group (e.g. reptiles or mammals). They are therefore now counted in the same clade as the dinosaurs.
prof. Dr. Luke Bouwens
Pleinlaan 2 1050 Ixelles