Question

Name the primitive phylum of bacteria and explain it

Answer 1

Bacterial phyla



Phylogenetic tree showing the diversity of bacteria, compared to other organisms.[1] Eukaryotes are colored red, archaea green and bacteria blue.

The bacterial phyla are the major lineages, known as phyla or divisions, of the domain Bacteria.

In the scientific classificationestablished by Carl von Linné,[2] each bacterial strain has to be assigned to a species (binary nomenclature), which is a lower level of a hierarchy of ranks. Currently, the most accepted mega-classification system is under the three-domain system, which is based on molecular phylogeny. In that system, bacteria are members of the domain Bacteria[3] and "phylum" is the rank below domain, since the rank "kingdom" is disused at present in bacterial taxonomy.[4][Note 1] When bacterial nomenclature was controlled under the Botanical Code, the term division was used, but now that bacterial nomenclature (with the exception of cyanobacteria) is controlled under the Bacteriological Code, the term phylum is preferred.

In this classification scheme, Bacteria is (unofficially)[Note 2] subdivided into 30 phyla with representatives cultured in a lab.[5][6][7] Many major clades of bacteria that cannot currently be cultured are known solely and somewhat indirectly through metagenomics, the analysis of bulk samples from the environment. If these possible clades, candidate phyla, are included, the number of phyla is 52 or higher. Therefore, the number of major phyla has increased from 12 identifiable lineages in 1987, to 30 in 2014, or over 50 including candidate phyla.[8] The total number has been estimated to exceed 1,000 bacterial phyla.[9]

At the base of the clade Bacteria, close to the last universal common ancestor of all living things, some scientists believe there may be a definite branching order, whereas other scientists, such as Norman Pace, believe there was a large hard polytomy, a simultaneous multiple speciation event.[10]