Identification key
A determination key is a system for the precise determination or classification of living beings , minerals or the like. Dealing with identification keys is within university courses, the identification exercises , courses of study Botany and Zoology practiced.
to form
The traditional keys are a sequence of questions or a list of characteristics, to which at least two possible answers are always offered. As long as several determination results are still possible, the same procedure is used to branch further. Depending on whether exactly two or more alternatives are available for the decision, a distinction is made between dichotomous and polytomous keys. Starting from the most general distinguishing features, the questions relate to increasingly detailed characteristics, until the end no selection is possible and, for example, an organism is usually precisely defined down to its type . The branching structure of the questions resembles a tree, but does not necessarily trace the systematic boundaries. Indeed, it is a decision tree .
There are also synoptic keys . In contrast to the traditional keys, the characteristics are not queried in sequence. It is a list of various properties according to which the objects to be determined can be distinguished. For the different features, all possibilities that this property can have are indicated. When combining the individual characteristics and their potential results, for example, one species or a small group of species can be inferred and others can be excluded. To further differentiate the remaining alternatives, further criteria can be used in order to infer the present type.
Often the objects to be determined with the properties named in the synoptic key cannot be classified with certainty, or the number of possible results is only slightly reduced for some characteristics, because z. B. a large number of species may have the characteristic more or less likely. For this reason, synoptic keys are often used in computerized identification keys.
Individual evidence
- ↑ Ruedi Winkler: Methods of determining fungi - problems and new ways . On: www.pilze.ch, 2008.