A superorganism is any aggregate of individual organisms that behaves like a unified organism. Members of a superorganism have highly specialized social cooperative instincts, divisions of labor, and are unable to survive away from their superorganism for very long. The standard example of a superorganism is an ant colony, but there are many others -- termite mounds, bee hives, wasp nests, coral reefs, fungal colonies, groves of genetically identical trees, etc.
Some have suggested that humans are each a superorganism, because in every typical human being is over 1013 to 1014 microorganisms performing a variety of tasks, but mainly helping with digestion. Microorganisms in the human body outnumber our cells over 10-to-1, and their genetic material outnumbers ours 100-to-1. Many of these have not been isolated or studied. The Human microbiome project, a $115 million US Dollars project by the National Institutes of Health, aims to identify and characterize as many of these microorganisms as possible, which include bacteria, archaea, and viruses.
In the iconic superorganism, an ant colony, there are specialized ants to deal with various tasks. Soldier ants to defend the colony, worker ants to gather food, a queen ant to lay eggs, etc. Termite mounds are similar. Termites actually construct elaborate cathedral mounds, which may reach 9 m (30 ft) high in extraordinary cases. All these colonies operate as unified entities. Soldier ants may willingly sacrifice themselves in defense of the nest, an unusual behavior among animals, which are usually shaped by evolution to be self-preserving.
Coral reefs are sometimes considered superorganisms because of the way they form a continuous mass of animals. Like other superorganisms, the constituent organisms of a reef have very similar, if not identical genetic structures. Although the coral animals in a reef do not actively cooperate, their presence as a habitat for a wide diversity of animals brings in so much food matter that these animals do cooperate, if unwittingly. Reefs have existed, minus a few gaps, since the beginning of the Cambrian era, about 542 million years ago.
Some thinkers have somewhat fancifully called human information networks the emerging signs of a global superorganism, but this is not very correct as humans have not evolved to cooperate in such large numbers. For most of our history, humans have cooperated in 100-200 person hierarchical tribes, where each individual is highly self-interested, the gene pool is diverse, and cooperation is anything but perfect. Global populations exceeding 5 million are a relatively recent phenomenon, and humans have not had time to evolve to acquire signature characteristics of the constituent members of a superorganism. Furthermore, there is no active selection pressure in this direction.
