taxonomic rank that includes species but not families
Taxonomic rank In his landmark publications, such as the Systema Naturae, Carl Linnaeus used a ranking scale limited to: kingdom, class, order, genus, species, and one rank below species. Today, nomenclature is regulated by the nomenclature codes. There are seven main taxonomic ranks: kingdom, phylum or division, class, order, family, genus, species. In addition, the domain (proposed by Carl Woese) is now widely used as one of the fundamental ranks, although it is not mentioned in any of the nomenclature codes. Also, this term represents a synonym for the category of dominion (lat. dominium), introduced by Moore in 1974.[4] Unlike Moore, Whoese et al. (1990) did not suggest a Latin term for this category, which represents a further argument supporting the accurately introduced term dominion.[5]
Food web In the simplest scheme, the first trophic level (level 1) is plants, then herbivores (level 2), and then carnivores (level 3). The trophic level is equal to one more than the chain length, which is the number of links connecting to the base. The base of the food chain (primary producers or detritivores) is set at zero.[3][13] Ecologists identify feeding relations and organize species into trophic species through extensive gut content analysis of different species. The technique has been improved through the use of stable isotopes to better trace energy flow through the web.[14] It was once thought that omnivory was rare, but recent evidence suggests otherwise. This realization has made trophic classifications more complex.[15]