I know teachers who work hard to enter the particular moral worlds of students. A high school teacher recently told me about his efforts not to condone but to understand why a student he admired had brought a gun to school.
In biological classification, rank is the relative level of a group of organisms (a taxon) in a taxonomic hierarchy. Examples of taxonomic ranks are species, genus, family, order, class, phylum, kingdom, domain, etc. A given rank subsumes under it less general categories, that is, more specific descriptions of life forms.
The species category, defined by a concept, denotes the rank of a species taxon in the Linnaean hierarchy. Biological species are reproducing isolated from each other, which protects the integrity of their genotypes. Degree of morphological difference is not an appropriate species definition.