Basics of Taxonomy
| Hierarchy of taxonomic levels (excluding intermediate levels)
Taxonomy, as a branch of biology, systematically records living things (and viruses). This division into a hierarchical system is traditionally associated with classification into a certain rank, such as species, genus or family, especially in organisms, but also in viruses, see virus taxonomy. In biology, a taxon is a group of living things (or viruses) that can be described by common characteristics and distinguished from other groups. The list of taxa is the field of taxonomy, the scientific classification of organisms according to internationally established nomenclature rules, see biological nomenclature. Taxonomic training is an important part of studying organismic biology. By delimiting the different taxa, a classification is made according to certain sequences of levels: |
| German | Latin | Example |
|---|---|---|
| domain | Dominion | Eukaryotes |
| Rich | Regnum | Animals |
| Underdark | Subregnum | Multicellular animals, multicellular organisms (Metazoa) |
| Department/Tribe | Division/Phylum | Chordates |
| Subdivision/subphylum, subphylum | Subdivisio/Subphylum | Vertebrates (Vertebrates, Vertebrata) |
| Class | Classis | Mammals (Mammalia) |
| subclass, subclass | Subclassis | Higher mammals |
| Infraclass | … | |
| Superordination | Superordo | Laurasiatheria |
| Order | Order | Predators |
| Subordination | Subordo | … |
| Partial order | Infraordo | … |
| Superfamily, superfamily | Superfamilia | Feline |
| Family | Family | Cats |
| Subfamily | Subfamilia | Small cats |
| Tribe | Tribe | … |
| subtribe | Subtribe | … |
| genus | genus | Old World wildcats |
| species, species | Species | Wildcat |
| Subspecies, race, subspecies | subspecies | European wildcat |
The species plays a key role here. A biological species is a group of natural populations that form a reproductive community and are reproductively isolated from other groups. The isolation mechanisms between the individual species are biological in nature, i.e. not based on external circumstances, but rather inherent in the living beings themselves. This definition is considered the optimal definition of a species because it is not arbitrary, "one could even go so far as to call it 'self-operational'" by "emphasizing the criterion of reproductive isolation from other populations."
Since the biological species concept cannot be applied to all life forms (generation times too long, sexual reproduction unknown, parthenogenesis), there are other species definitions such as the morphological species (the most frequently used species definition), the phylogenetic species (due to phylogenetic relationships) or the ecological species in which morphologically identical or similar species are treated as different species if they occur geographically separately.
With the publication of Systema Naturae by Carl Linnaeus, binary (in zoology also binominal) nomenclature became established. The first part of the name refers to the genus, the second is the epithet for the species.
Methods
Traditional methods were based on morphological characteristics, such as body structure in animals or flower structure in plants. Later, findings from the fields of microscopy, physiology, biochemistry and genetics were incorporated into the taxonomic consideration. Recently, automated, computer-based identification systems are being tested that are intended to dramatically improve the accuracy and speed of a determination (see below).
Modern biological systematics is more profound. Phylogenetic relationships play a role in this. In the system, the different taxa are classified into a hierarchical family tree that is intended to reflect their evolutionary ancestry. The rules of cladistics are now considered the standard for classifying organisms, i.e. H. a taxon should be monophyletic.
Source: From File:Biological classification S Pengo.svg: Peter Halasz (User:Pengo) / *derived work TomCatX - File:Biological classification S Pengo.svg, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=15216142
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