Bringing Order out of Chaos
The concept of grouping objects together in larger clusters is very basic to human needs. Such ideas are built into all human languages and cultures.
Every language uses 'specific identifiers', specific words or terms for an object. Nouns such as 'bluejay', 'finch', 'sparrow', 'thrush' and 'canary', are used to specifically identify unique objects or creatures. Any naturalist told that you had just seen a 'canary', would instantly be able to picture the small, yellow feathered avian you were talking about.
Languages also have other words that are used to identify things, but with a different purpose. These are grouping words that are used in a more general way to reference groups or clusters of objects. Use the term 'birds' and your listener will have a general idea of what you are talking about. They will be able to see in their minds a feather covered creature that may be capable of flight, lays eggs, has scaly legs and a beak. But the image will not be as clear as if you had said 'canary'.
Such a way of organizing a language, or set of knowledge, appears to be universal in human cultures and extends back, probably into very early periods of human intellectual evolution. Grouping seems to be a mental exercise that proto-humans found both useful and worthwhile.
Why put objects and creatures into groups this way?|
Using grouping words in every day language certainly speeds up communication. It is easier and quicker to say "I saw a bird today", than it is to carefully identify the specific bird you saw, especially if your listener may not be an ornithologist. But there are other advantages as well.
Putting objects into carefully selected groups makes it possible to store more information in a way that also makes it easier to find again. Think of a dictionary. Words in a dictionary are grouped first by their initial letter, then by then by the nature of their second letter, and so on. Once the user of a dictionary has mastered the principle taxonomy used, it becomes very easy to find the meaning of any word (provided you know how to spell it!).
Knowledge storage and retrieval are less arduous and less arbitrary when a properly devised grouping system is used, and fewer mistakes are made and fewer pieces of data are lost for ever.
Carrying out such a grouping exercise also forces the classifier to compare different objects or organisms. Questions have to be asked about the relative weight to give certain characters or classifying procedures. Members of groups are easier to summarize and trends more easily seen. When new objects or organisms are discovered, a good grouping system makes it easier to place the newcomer and define its position.
When the 'noise' of thousands of specific objects have been reduced to a clarifying few groups, it then becomes possible to see larger generalizations among and between the groups themselves. New relationships may be discovered and if the objects are living organisms, it may be possible to detect evolutionary relationships and patterns that it was hard or impossible to see when dealing with thousands of specific objects.
Grouping, or classification appears to be a very 'human' activity both culturally and scientifically, but ...
It is completely artificial and no more than a trick of the human mind. No organism cares or worries about the group in which it belongs. Humans put them in groups for their own convenience, not because it is required by ecology or for their survival. Never the less, it is a useful trick of the human mind and one that certainly brings order to the chaos of diversity.