Question

What is the role of keys in taxonomy? Illustrate with an example.

Answer 1

Taxonomic keys is an important aid that is used in the identification of different plants and animals based on similarities and dissimilarities of different plants or animals.

Complete answer:

1. Keys contain two statements that are contradictory to each other and they are known as a couplet where a single statement is known as a lead.
2. Any unknown organism can be easily identified by using the contradictory statements of the key.
3. The keys where the choice is made between alternate couplets are known as dichotomous keys and in these types of keys, the characters are divided into small groups.
4. The dichotomous keys are of two types that are indented key and bracketed key.
5. Indented keys are those where the sequence of options is available for multiple characters.

Example: The genus of the family Ranunculaceae can be identified by observing the carpel and fruit of the given sample, if the carpel has a single ovule and the fruit is an achene, leaves are compound and opposite and without tendril and petals are absent then the genus is clematis.

Bracketed keys contain only a pair of contrasting characters for the identification of plants and animals. Example: Leaves alternate, radical represents the genus Anemone.

Note: The Couplet of the key which contains two contrasting statements in the key represent the choice made between the two options by comparing and identifying each option where only one of the options is accepted and the other statement is rejected and hence the keys are said to be analytical.