A microbiota is "the ecological community of commensal, symbiotic and pathogenic microorganisms that literally share our body space." Joshua Lederberg  coined the term, arguing the importance of microorganisms inhabiting the human body in health and disease. Many scientific articles distinguish<unk>  and microbiota to describe either the collective genomes of the microorganisms that reside in an environmental niche or the microorganisms themselves, respectively.  However by the original definitions these terms are largely synonymous.
The human body contains over 10 times more microbial cells than human cells, although the entire<unk>  only weighs about 200 grams. Because bacteria are 10-100 times smaller than human cells, the entire<unk>  weighs about 200 grams, with some weight estimates ranging as high as 3 pounds (approximately 48 ounces or 1,400 grams). Some regard it as a "newly discovered organ" since its existence was not generally recognized until the late 1990s and it is understood to have potentially overwhelming impact on human health. Modern techniques for sequencing DNA have enabled researchers to find the majority of these microbes, since the majority of them cannot be cultured in a lab using current techniques. The human<unk>  may have a role in auto-immune diseases like diabetes, rheumatoid arthritis, muscular dystrophy, multiple sclerosis, fibromyalgia, and perhaps some cancers. A poor mix of microbes in the gut may also aggravate common obesity. Since some of the microbes in our body can modify the production of neurotransmitters known to be found in the brain, it may also relieve schizophrenia, depression, bipolar disorder and other neuro-chemical imbalances.
The microbes being discussed are generally non-pathogenic (they do not cause disease unless they grow abnormally); they exist in harmony and symbiotically with their hosts.
Microbiome
Vector
Vector 
Flora
Nucleosol
Biological system
Biomarker
Transcriptome