Question

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

Answer 1

Method for choosing the hierarchy of a classification:

1. Classification of organisms based on hierarchical distribution is based on the fundamental characteristics of an organism.
2. Hence, the most basic characteristics are taken into consideration for categorizing an organism into a particular hierarchy.
3. For example, the major difference in the fundamental characteristics of plants and animals that put them into a different hierarchy of classification is that plants have cell walls whereas animals do not.
4. The most common characteristic used for classifying organisms into a hierarchical classification is locomotion.
5. After classifying organisms based on a single fundamental characteristic other basic characteristics can be taken into consideration to further classify them into a particular niche.
6. The major characteristics used for classification are the complexity of cell structure, body organization, and mode of nutrition.

The three main characteristics used for a hierarchical classification:

A. The complexity of cell structure:

1. The cell structure complexity is used to classify organisms into a particular hierarchical group.
2. The presence of cell walls, cell membrane, a well-defined nucleus, etc., are taken into consideration while categorizing an organism as eukaryotic or prokaryotic.

B. Body organization:

1. While categorizing organisms based on body organization, it is taken into account if the organism is unicellular or multicellular.
2. Unicellular organisms can be a prokaryote or a eukaryote.
3. Whereas a multicellular organism is fundamentally more complex and differentiated into tissue and complex organs.

C. Mode of nutrition:

1. Organisms can also be characterized based on their mode of nutrition.
2. Autotrophic producers can prepare their own and consumers which are heterotrophic and depend on others for meeting their nutritional requirements fall into different hierarchical groups.
3. Heterotrophs consume the food prepared by consumers or consumed by other primary consumers.
4. Hence, due to differences in nutritional requirements different organisms also have different body organizations.