Biological Classification - Types

Description:

There are three types of classification −

Artificial System of Classification

• Use of one or two morphological characters for grouping.
• Some artificial system uses habit and habitat for this purpose.
• Aristotle classified animals into enaima (with red blood) and anaima (without red blood).
• Aristotle classified animals on the basis of their habitat into aquatic, terrestrial and aerial.

Drawbacks of artificial system

• It does not study homology.
• They system considers one or two morphological traits which has no bearing on actual status of taxa.
• The characters used in artificial classification shows evolution. Therefore, they do not reflect any natural relationship.
• Some characters used in artificial system of classification get changed with change in environment, like biennial and annual habit of radish.

Natural System of Classification

• A number of characters are compared so as to bring out natural similarities and dissimilarities.

• This system uses characters which are relatively constant like morphological, anatomical, cytological etc.

• The characteristics are helpful in bringing out maximum number of similarities in a group and comparable differences with other groups of organisms.

Natural system of classification is better than artificial system of classification because −

• Study of each and every organism is performed.
• There is stress on comparative study.
• It brings out natural relationships amongst organisms.
• It places only related organisms in a group.
• This system prevents coming together of unrelated organisms.

Phylogenetic System of Classification

• Classification based on evolutionary relationship of organisms.

• Based on evolutionary concept from Darwin’s book – On the Origin of species by Means of Natural.

  Selection: The Preservation of Favoured Races in the Struggle for Life (1859).

The difference between Natural and Phylogenetic System of Classification is −