This was a headline in the Scientist of June 13, 2012. The corresponding article by Ed Young based on The Human Microbiome Project Consortium, Structure, function and diversity of the healthy human microbiome (Nature, 486: 207-214, 2012) went on as follows:
The human body is largely not human. It contains trillions of microbes that outnumber our own cells 10 to 1, affecting our health and behavior. Now, an international consortium of around 200 scientists has mapped this diverse microbial community at an unprecedented level of detail, and shown just how much it varies from person to person.
Presumably, the main surprise was how these massive bug populations vary in makeup between individuals, while by and large fulfilling the same tasks for each person:
In cataloguing the healthy human microbiome, the HMP (Human Microbiome Project) has already yielded some surprises. For example, although each body part is characterised by some signature microbial groups, no species was universally present across every volunteer …
For me – if these observations shows us anything – it is the incredible creativity within the evolutionary process to make things work at the living organism level, as well as the symbiotic nature of life, i.e., no life-form is independent from some other form of life.
And as well as we might be able to catalog life by means of discerning distinct or discrete entities, in the end all life is as one and the living entity that is our planet Earth.