DENDROLOGY

Detailed explanation-1: -For example, organisms placed in the same genus are always more closely related to each other than those in different genera in the same family, and organisms in the same family are more closely related than those in different orders. Ranking within more inclusive taxa reflects degree of common ancestry.

Detailed explanation-2: -Levels of Classification. The classification system commonly used today is based on the Linnean system and has eight levels of taxa; from the most general to the most specific, these are domain, kingdom, phylum (plural, phyla), class, order, family, genus (plural, genera), and species.