Classification

In the syllabus and the exam

Classification is the process of arranging organisms into a hierarchy of groups based on shared features, and candidates are expected to recall the standard hierarchy from broadest to narrowest, kingdom, phylum, class, order, family, genus, species, and to explain that organisms in a lower, more specific group share more features and are more closely related than organisms that only share a higher, broader group. Exam questions often give a table or a dichotomous key style diagram and ask candidates to classify unfamiliar organisms step by step using observable features, such as presence or absence of a backbone, type of body covering, or method of reproduction. A common error is confusing classification with identification: classification is building or using the overall grouping system itself, while identification is placing one specific organism into an existing group using a key. Candidates should also know that classification is not fixed forever; it is revised as new evidence, especially from molecular and genetic studies, shows that organisms once grouped together are not as closely related as their physical appearance suggested, or vice versa. The five-kingdom classification system (Monera, Protista, Fungi, Plantae, Animalia) is the version most commonly tested at this level, and candidates should be able to state the defining feature that places an organism into each kingdom, such as the absence of a membrane-bound nucleus in Monera.

Example

Placing a rose, a hibiscus and an orchid all within the plant kingdom, then sorting them into different families based on flower structure, is an example of classification working from a broad group down to a more specific one.

Related terms

SpeciesBinomial nomenclatureBiodiversity

Source:SRC-DSKP-EN