A Guide to the Nomenclature and
Classification of Organisms
HELEN A. STAFFORD
Biology Department, Reed College, Porthnd, Oregon
Since the time of Linneaus, all organisms have been given Latin
specific and generic names, the latter including groups of species more
closely related to each other than to other groups of species. Even before evolution was accepted as a valid theory, biologists realized that
genera could be arranged in a series of higher or more inclusive groups,
denoting further interrelationships, on the basis of sets of characteristics held in common. Such classification systems tended to be artificial
ones, but as more information concerning morphological, physiological,
and biochemical characteristics of organisms was assembled, more
natural systems were devised. Once evolution was accepted, these
natural classification systems reflected the phylogenetic picture pieced
together from paleontology, and from the study of the comparative
aspects of modern forms.
The basic conflict between partly artificial classification systems,
often more complete and more useful for purposes of strict identification, and the natural phylogenetic systems, sometimes less practical for
taxonomic purposes, has been discussed frequently (1-4). Furthermore, a phylogenetic scheme suitable for modern forms might be quite
unsatisfactory if fossil forms are included. As the present treatise is concerned with the comparative biochemistry of extant forms, any purely
fossil groups are not included in the classification scheme presented,
although such fossil forms often are the basis of any phylogenetic
scheme.
While numerous subdivisions and even higher taxonomic categories
are frequently used, the following taxa, arranged in order of decreasing magnitude, are the generally accepted groupings used to classify
related organisms:
Phylum (or Division in the Plant Kingdom)
Class
Order
Family
Genus
Species
xvii
Classification of Organisms
HELEN A. STAFFORD
Biology Department, Reed College, Porthnd, Oregon
Since the time of Linneaus, all organisms have been given Latin
specific and generic names, the latter including groups of species more
closely related to each other than to other groups of species. Even before evolution was accepted as a valid theory, biologists realized that
genera could be arranged in a series of higher or more inclusive groups,
denoting further interrelationships, on the basis of sets of characteristics held in common. Such classification systems tended to be artificial
ones, but as more information concerning morphological, physiological,
and biochemical characteristics of organisms was assembled, more
natural systems were devised. Once evolution was accepted, these
natural classification systems reflected the phylogenetic picture pieced
together from paleontology, and from the study of the comparative
aspects of modern forms.
The basic conflict between partly artificial classification systems,
often more complete and more useful for purposes of strict identification, and the natural phylogenetic systems, sometimes less practical for
taxonomic purposes, has been discussed frequently (1-4). Furthermore, a phylogenetic scheme suitable for modern forms might be quite
unsatisfactory if fossil forms are included. As the present treatise is concerned with the comparative biochemistry of extant forms, any purely
fossil groups are not included in the classification scheme presented,
although such fossil forms often are the basis of any phylogenetic
scheme.
While numerous subdivisions and even higher taxonomic categories
are frequently used, the following taxa, arranged in order of decreasing magnitude, are the generally accepted groupings used to classify
related organisms:
Phylum (or Division in the Plant Kingdom)
Class
Order
Family
Genus
Species
xvii