What is the phylogenetic classification based on?

Hint: The basic definition of classification is the grouping of things into taxonomic groups based on observed similarities of their characteristics. It facilitates a simple understanding of the group as a whole. Biological classification is a scientific process that involves grouping organisms into a hierarchical series of groups and subgroups based on their similarities and differences.

Complete answer:
Phylogenetics is a branch of systematics in biology that deals with inferring evolutionary history and relationships among or within groups of organisms (e.g. species, or more inclusive taxa). Phylogenetic inference methods that evaluate observed heritable traits, such as DNA sequences or morphology, often under a specified model of evolution, hypothesize these relationships.
 Phylogenetic classification systems show how entities have evolved. The acceptance of natural selection and the doctrine of evolution put forward by Charles Darwin in his book "On the Origin of Species" by Natural Selection led to the creation of this classification system.
Darwin proposed that modern plants and animals evolved from a few ancestral ones after undergoing a few periodical changes. As a result, phylogenetic classification is based on a group of entities' evolutionary descent. A cladogram and a phylogram are used to show relationships.

Hence, the Phylogenetic classification system is based on evolutionary ancestry.

Note:
The identification, naming, and classification of organisms are all part of the taxonomy. Many systematists believe that only monophyletic taxa should be recognized as named groups and that classifications should now be based on phylogenetic data. The extent to which classification is based on inferred evolutionary history varies by taxonomic school.