Numerical taxonomy
Encyclopedia
Numerical taxonomy is a classification system
in biological systematics
which deals with the grouping by numerical methods of taxonomic units
based on their character states.. It aims to create a taxonomy
using numeric algorithms like cluster analysis rather than using subjective evaluation of their properties. The concept was first developed by Robert R. Sokal
& Peter H. A. Sneath in 1963 and later elaborated by the same authors. They divided the field into phenetics
in which classifications are formed based on the patterns of overall similarities and cladistics
in which classifications based on the branching patterns of the estimated evolutionary history of the taxa. Note: in recent years many authors treat numerical taxonomy and phenetics as synonyms despite the distinctions made by those authors.
Although intended as an objective classification method, in practice the choice and implicit weighing of characteristics is, of course, influenced by available data and research interests of the investigator. What was made objective was the introduction of explicit steps to be used to create phenograms and cladograms using numerical methods rather than subjective synthesis of data.
Biological classification
Biological classification, or scientific classification in biology, is a method to group and categorize organisms by biological type, such as genus or species. Biological classification is part of scientific taxonomy....
in biological systematics
Systematics
Biological systematics is the study of the diversification of terrestrial life, both past and present, and the relationships among living things through time. Relationships are visualized as evolutionary trees...
which deals with the grouping by numerical methods of taxonomic units
Taxon
|thumb|270px|[[African elephants]] form a widely-accepted taxon, the [[genus]] LoxodontaA taxon is a group of organisms, which a taxonomist adjudges to be a unit. Usually a taxon is given a name and a rank, although neither is a requirement...
based on their character states.. It aims to create a taxonomy
Taxonomy
Taxonomy is the science of identifying and naming species, and arranging them into a classification. The field of taxonomy, sometimes referred to as "biological taxonomy", revolves around the description and use of taxonomic units, known as taxa...
using numeric algorithms like cluster analysis rather than using subjective evaluation of their properties. The concept was first developed by Robert R. Sokal
Robert R. Sokal
Robert Reuven Sokal is an Austrian-American biostatistician and anthropologist. Distinguished Professor Emeritus at the State University of Stony Brook, New York, Sokal is a member of the National Academy of Sciences and the American Academy of Arts and Sciences...
& Peter H. A. Sneath in 1963 and later elaborated by the same authors. They divided the field into phenetics
Phenetics
In biology, phenetics, also known as taximetrics, is an attempt to classify organisms based on overall similarity, usually in morphology or other observable traits, regardless of their phylogeny or evolutionary relation. It is closely related to numerical taxonomy which is concerned with the use of...
in which classifications are formed based on the patterns of overall similarities and cladistics
Cladistics
Cladistics is a method of classifying species of organisms into groups called clades, which consist of an ancestor organism and all its descendants . For example, birds, dinosaurs, crocodiles, and all descendants of their most recent common ancestor form a clade...
in which classifications based on the branching patterns of the estimated evolutionary history of the taxa. Note: in recent years many authors treat numerical taxonomy and phenetics as synonyms despite the distinctions made by those authors.
Although intended as an objective classification method, in practice the choice and implicit weighing of characteristics is, of course, influenced by available data and research interests of the investigator. What was made objective was the introduction of explicit steps to be used to create phenograms and cladograms using numerical methods rather than subjective synthesis of data.
See also
- Hierarchical clusteringHierarchical clusteringIn statistics, hierarchical clustering is a method of cluster analysis which seeks to build a hierarchy of clusters. Strategies for hierarchical clustering generally fall into two types:...
- Hierarchical clustering of networks
- CladisticsCladisticsCladistics is a method of classifying species of organisms into groups called clades, which consist of an ancestor organism and all its descendants . For example, birds, dinosaurs, crocodiles, and all descendants of their most recent common ancestor form a clade...
- PheneticsPheneticsIn biology, phenetics, also known as taximetrics, is an attempt to classify organisms based on overall similarity, usually in morphology or other observable traits, regardless of their phylogeny or evolutionary relation. It is closely related to numerical taxonomy which is concerned with the use of...