Question

How would you choose between two characteristics to be used for developing a hierarchy in classification?

Answer 1

For developing a hierarchy of classification, the fundamental characteristics among several other characteristics should be chosen first. If a particular character is present or visible in a small number of organisms and a larger number of organisms, that character should be considered basic. By choosing these basic characteristics, we can make further broad divisions in living organisms as the next level of characteristics. This in future goes on to form a hierarchy of characteristics of an individual or a group of individuals.

Complete answer:
The overall character or the gross character of an organism or a group of organisms will form the basis of the start of the hierarchy, while the fine character will form the basis of further steps of the single hierarchy.

For example:

Presence of the vertebral column in human beings can be taken under vertebrates. Here, all human beings have vertebrates. Hence, it is a basic character of humans. While the other characters which are specific to human beings only, can be considered as the next level characters.

Presence of four limbs makes them members of Tetrapoda. The members of tetrapoda can be initially identified by the presence of four limbs. These limbs are the basic characters of tetrapods , while they also have several organisms which can be differentiated or classified depending on several other characteristics.

Presence of mammary glands keeps them under mammalia. The mammals contain the mammary glands; this is considered as the basic characters of mammals. Several other characters like the presence of hairs are also a basic character of mammals. Also, other characters are present like teeth and dental formula can be used further to classify the mammals.

Additional information:
The taxonomic hierarchy can be defined as the process of arranging various organisms into successive levels of the biological classification. This arrangement can be done either in a decreasing or an increasing order, from kingdom to species and vice versa.
After kingdoms, the subsequent categories of increasing specificity of all organisms are: phylum, class, order, family, genus, and species.

Note: The classification or the arrangement of hierarchy makes the study of different kinds of organisms much easier. It helps us to know about the inter-relationship, similarities and differences among the various organisms. The evolution of organisms can also be known through classification.