Superorganisms…

by Jim Caryl

[ratings]

NO, don’t get excited, I said super organisms. Yesterday’s The Scientist led with an article on Super organisms, which reminds me of my invertebrate neural and endocrinology lectures of years past. I used to be fascinated by the idea of super organisms, which is simply an organism of many organisms.

Being a prokaryotic biologist, I tend to think of things at the scale of planktonic (free-living) single cells, and occasionally we enjoy the concept of cooperative living in biofilms or other more complex structured consortia like stromatolites. Ultimately, evolution has resulted in multicellular organisms, some of which were further refined into organisms consisting of many different tissues with disparate characteristics; most people are not unfamiliar with this.

An interesting idea in biology is the idea of a super organism, where parallels can be drawn between the essential components of a complex higher organism, such as a mammal, and individual organisms within the super organism:

It is a rather contentious idea as it runs into the semanto-scientific diction of what exactly constitutes an organism. Are we limited by our usual scale-interpretation as Humans, where an abstract idea of a super organism clashes with our own biological recognition of what constitutes an organism? The big question is of course, how can such a super organism evolve? This is one of those great challenges that evolutionary biologists love.

At what scale does natural selection, the active force of evolution, have its effect? Does it act at the level of the individual? Yes, probably; I am still with Dawkins on the idea of selection acting at the level of the gene. However, for natural selection to have an effect, it depends on individual differences within a population, and crucially, on the ability of the “fittest” individual to survive and reproduce. However, in Ant colonies the Ants are sterile drones; the reproductive entity of a such a super organism is the queen of an Ant colony.

Thus we have a situation where “unfit” worker Ants can result in the collapse of a colony, therefore selection feeds back to the Queen where reproductive success is dependant upon producing workers that are capable of fulfilling their roles in the provision of food, looking after eggs, defending the colony and building infrastructure; thus a very indirect form of selection. So is the superorganism being selected or not?

Good question,  it’ll be fun finding out.

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