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In phylogenetics, a single-access key (also called dichotomous key, sequential key, analytical key, [1] or pathway key) is an identification key where the sequence and structure of identification steps is fixed by the author of the key. At each point in the decision process, multiple alternatives are offered, each leading to a result or a ...
In biology, an identification key, taxonomic key, or frequently just key, is a printed or computer-aided device that aids in the identification of biological organisms. Historically, the most common type of identification key is the dichotomous key , a type of single-access key which offers a fixed sequence of identification steps, each with ...
A branching identification key within taxonomy (the practice and science of categorization or classification), is a presentation form of a single-access key where the structure of the decision tree is displayed graphically as a branching structure, involving lines between items. [1]
Molecular studies by molecular systematists, based on DNA analysis, in the early 21st century have revealed new relationships among mammal families. Classification systems based on molecular studies reveal three major groups or lineages of placental mammals, Afrotheria, Xenarthra, and Boreoeutheria. which diverged from early common ancestors in the Cretaceous.
Taxonomy is that part of Systematics concerned with topics (a) to (d) above. A whole set of terms including taxonomy, systematic biology, systematics, scientific classification, biological classification, and phylogenetics have at times had overlapping meanings – sometimes the same, sometimes slightly different, but always related and ...
The idea of a tree of life arose from ancient notions of a ladder-like progression from lower into higher forms of life (such as in the Great Chain of Being).Early representations of "branching" phylogenetic trees include a "paleontological chart" showing the geological relationships among plants and animals in the book Elementary Geology, by Edward Hitchcock (first edition: 1840).
Determination now relies on modern taxonomy to define the identify of organisms. Taxonomy is the branch of biology which deals with identity, nomenclature and classification. The term was first coined in 1813 by Swiss botanist Augustin Pyramus de Candolle. Carl Linnaeus, who began modern taxonomy, used the term 'systematics' himself.
In biology or medicine, a multi-access key is an identification key which overcomes the problem of the more traditional single-access keys (dichotomous or polytomous identification keys) of requiring a fixed sequence of identification steps.