Modern Biological Classification

Taxonomy

Taxonomy is the science that deals with the classification of organisms.

The Contribution of Carolus Linnaeus

Carolus Linnaeus, a Swedish botanist, developed a simple classification system that forms the basis of our modern method of classification. At the start of the 18th century about 10,000 kinds of organisms were known. By the end of that century over 70,000 kinds were known. Linnaeus tried to develop a classification system for this large number of organisms. By 1753 his system was well developed and modern taxonomy began.

The Basis for Linnaeus Classification 

Biologists use the word diversity to mean differences, or the number of kinds of living things.
There seem to be so many kinds of living things and they seem to be so different from one another. Yet, if we study them closely, we can see many likenesses. For example, at first glance lions, horses, humans, and mice seem to have little in common. A closer look however, shows that all have hair, a distinct head, four limbs, two ears, and warm blood. That is, they have similar structural features.
Linnaeus decided to use structural features as the basis for his classification system. Therefore, he grouped organisms according to their structural similarities. These organisms with very similar structural features were considered to be the same species. Thus all modern-day humans belong to one species, all house cats belong to one species, and all sugar maple trees belong to one species.