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Edward Hitchcock's fold-out paleontological chart in his 1840 Elementary Geology. Although tree-like diagrams have long been used to organise knowledge, and although branching diagrams known as claves ("keys") were omnipresent in eighteenth-century natural history, it appears that the earliest tree diagram of natural order was the 1801 "Arbre botanique" (Botanical Tree) of the French ...
The scientific work of deciding how to define species has been called microtaxonomy. [26] [27] [20] By extension, macrotaxonomy is the study of groups at the higher taxonomic ranks subgenus and above, [20] or simply in clades that include more than one taxon considered a species, expressed in terms of phylogenetic nomenclature. [28]
A clade is by definition monophyletic, meaning that it contains one ancestor which can be an organism, a population, or a species and all its descendants. [note 1] [10] [11] The ancestor can be known or unknown; any and all members of a clade can be extant or extinct.
DNA barcoding is a method of species identification using a short section of DNA from a specific gene or genes. The premise of DNA barcoding is that by comparison with a reference library of such DNA sections (also called "sequences"), an individual sequence can be used to uniquely identify an organism to species, just as a supermarket scanner uses the familiar black stripes of the UPC barcode ...
A monotypic taxon is a taxonomic group which only contains a single subgroup (e.g., a genus with only one known species, even a subphylum with one family with one genus). In such a case, the ranks with identical member organisms should not be separated into different articles, and the article (if there is no common name) should go under the ...
Binomial nomenclature for species has the effect that when a species is moved from one genus to another, sometimes the specific name or epithet must be changed as well. This may happen because the specific name is already used in the new genus, or to agree in gender with the new genus if the specific epithet is an adjective modifying the genus ...
Some Tri-Cities residents will receive letters from the cities where they live notifying them that their homes contain water pipes made of an unknown material that may potentially include lead.
While typical water samples can have the DNA degrade relatively quickly, the aquatic sediment samples can have useful DNA two months after the species was present. [55] One problem with aquatic sediments is that it is unknown where the organism deposited the eDNA as it could have moved in the water column.