Identification key

Under a determination key is defined as a system for the accurate determination or classification of organisms, minerals or the like.

Molding

In the traditional keys, there is a sequence of questions or a Aufzähling of features, which is always at least two possible answers are offered. As long as still more determination results are possible, further branching according to the same procedure. Depending on whether exactly are two ways or more alternatives in the decision available, dichotomous key and polychotome be distinguished. The questions relate on the basis of the most common distinguishing features on increasingly detailed idiosyncrasies, to the end no more choice is possible, for example, an organism usually is determined up to his style exactly. The branch structure of questions similar to a tree, but does not necessarily traces the systematic limits. In fact, it is a decision tree.

Moreover, there is synoptic key. In contrast to the traditional keys, the features are interrogated sequentially divided. It is a list of characteristics according to which the objects to be determined, can be distinguished. The different features all possibilities are shown, which can have this property. So it can be concluded, for example, in a way or a small group of species and exclude others in the combination of individual features and their potential results. For further differentiation of remaining alternatives other criteria can be used to deduce the present type.

It often happens that the objects to be determined with the properties mentioned in the synoptic key not sure divide or the number of possible outcomes is reduced when some features only slightly, for example, because a large number of species can have the feature more or less likely. For this reason, synoptic keys often found in computer-aided identification keys application.