Mycobacterium species represent both environmental and pathogenic organisms that fall into two major groups: tuberculosis complex such as M. tuberculosis and M. bovis (MTBC), and Non-tuberculous mycobacteria (NTM) such as M. avium complex, M. abscessus and M. smegmatis.
But that no longer appears to be the case.The Burgess Shale came soon after a period of time known as the Cambrian explosion, when most major groups of complex animals arose over a surprisingly short period.
In evolutionary studies the Cambrian is the period when most major groups of complex animals appeared (the Cambrian explosion).
There are also two other major groups: 1) the T. mauritanica complex present in North Africa and Europe; and 2) the clade formed by the T. fascicularis/ deserti complex, T. neglecta and T. mindiae, occurring only in North Africa.
The genus Mycobacterium contains more than 140 species [ 1], which are separated in three major groups, that is, M. tuberculosis complex (MTBC), M. leprae, and mycobacteria other than MTBC and M. leprae, collectively referred to as nontuberculous mycobacteria (NTM).
Despite the distance, rugged terrain, and length of time between field collection and transport to the laboratory, roots of epiphytic, lithophytic and terrestrial orchids yielded all major groups of fungi in the Rhizoctonia complex (Ceratobasidium, Tulasnella, Sebacina).
In addition, classification into only four major groups appears to be an oversimplification of a more complex reality.
The grouping in nematodes is more complex: there appears to be three major groups of OTOPLs, as in vertebrates and arthropods, but each group itself contains two or more paralogous groups as a result of species-specific gene duplications.
Of the major groups of saprotrophs, fungi are among the most efficient at decomposing complex organic molecules and recycling those nutrients back into the ecosystem.
The two major groups of cells are prokaryotic and eukaryotic, with eukaryotic cells being more complex.
