History of classification
Classification of living organism is probably as old as human civilization. Organisms have been grouped on different basis at different periods of time. The earliest classification was probably on the basis of utility to man. Plants and animals were classified on different basis such edible and non edible ones, useful and harmful ones and so on.
Artificial system of classification
The earliest attempt towards classification of living organisms is seen in the works of many ancient philosophers in Greek and in India. The information available from many ancient scriptures of our country indicates the attempts made by Indians towards classification of plants and animals. An ancient sage by name Charaka who lived in the first century AD, had listed about 340 plant types and about 200 animals types in his treatise Charaka Samhitha. Another ancient sage by name Parashara in his treatise Vrikshayurveda had given a vivid description of plants based on the characteristics in flowers. He had divided plants into several "gangs" (Families) based on these characters. The description of characters for these ganas, given by Parashara, is very close to the ones given by modern taxonomists.
Aristotle, the famous Greek philosopher(384-322BC) had identified different types of plants and animals. Apart from this, he described some organisms under an " Intermediate group" Indicating that such organisms could be placed neither under " Plants" nor under "animals".
These and many other examples of ancient classification systems, we're based mainly on superficial characteristics. Such systems of classification are hence described as artificial system of classification.
The artificial system of classification has some serious drawbacks
- The criteria used for classification are superficial and do not reflect the natural relationships.
- The system does not reflect the evolutionary relationship between the organisms.
- Many unrelated organisms are placed in the same group on the basis of their dwelling place.
- Closely related organisms have been placed in different groups because of the difference in their habitat, feeding, etc.
Natural system of classification
As science became a part of human life, the classification of living organisms had to undergo a thorough modification. The advent of microscope in the 17th century opened up a new world of organisms that were hitherto unexplored, the world of microorganisms. It was hard to believe the vast diversity that existed in the microorganisms. Scientists started being investigated. As a result, more and more similarities and differences started emerging between the different groups in both plants and animals. This led to a more systematic and scientific approach to classification, which is now known as the natural system of classification.
The natural system of classification has specific advantages over the artificial system of classification they are
- It avoids the heterogeneous grouping of unrelated organisms.
- It helps in placing only related groups of organisms together.
- It indicates the natural relationships among organisms.
- It also provides a clear view on the evolutionary relationship between different groups of living organisms.
The initial attempt towards a natural system of classification came from an English biologist John Ray(1927-1705). He identified a large number of plants and animals based on natural relationships among themselves and classified them into specific groups. He was probably the first biologist to have developed the modern concept of a species. He described the species as an assemblage of individuals derived from similar parents and having the ability to pass on their characteristics to the subsequent generations. He published a three volume compendium Historia General is Plant arum in which he has given a detailed description of over 18,000 types of plants.
Contributions of Corollus Linnaeus
The greatest contribution to the natural system of classification is that Corollus Linnaeus he recognised species as the basic natural unit of classification. He used four specific categories. Another significant contribution from Linnaeus is that he developed and popularized a system of giving a scientific name to a plant or an animal. The scientific name had two words the first representing name of the genus and the second representing name of the species. This system came to be known as binomial nomenclature.
It is because of these significant contributions that Linnaeus is commonly described as Father of Modern Taxonomy.