Taxon is just a level of grouping of organisms. The grouping is based on certain easily observable characters. These characteristics are very common among them and are easy to observe. By remembering their rank or their taxon we can memorise these groups of organisms. The characters on which they are classified are totally different from the classification of another taxon. So, these taxonomic groups are just distinct biological entities that must not be thought of as random aggregates of animals that are based on their morphological features.