What is Phylum?
Phylum comes from the greek term phulon, it is the taxonomic rank above class and under kingdom. A phylum can be described in to way: as a group of organisms with a certain degree of morphological similarity or as a group of organisms with a degree of evolutionary relatedness. The concept of phyla has change greatly since its first Linnaean use, a definition of a phylum based on body plan was proposed by paleontologists Graham Budd and Soren Jensen where they are defined as "a set of characters shared by all its living representatives. This definition was posited because of the fact that extinct organisms are difficult to classify into modern phylum.