Peter Bentley

Digital Biology


The Creation of Life inside Computers and How it Will Affect us

Headline Book Publishing 2001


KEYWORDS : SUPERORGANISMS - social insects - ants - nests - organisms - self- organisation -collective decisions - choices - plans - intelligence

pg 107

Superorganisms

Social insects have been building cities since before we were living in caves. They have been co-operating, communicating and solving difficult problems before our predecessors even knew how to climb trees. They have been looking after themselves, collecting forward, nursing their young and removing their dead before there were even such things as mammals.

Ants build complicated cities, regulate temperatures, maintain nurseries, farm aphids, co-operate to carry things, teach each other where food is, find the shortest path from the food back home, and so on. Ants invade other nests, use chemical warfare, steal larvae and then enslave the ants when they grow.

Surely all these impressive accomplishments need somebody in charge to direct the activities - some bosses to order everyone about? When we build something, there's always someone who decides when and where it gets built, and someone to design the thing. When we go to war, we have generals to direct our armies.

Social insects are not really any cleverer than any other kind of insect. The single ant is stupid. Indeed, every single ant is stupid. How, then, can a colony of ants become clever? To try to answer this difficult question we must stop thinking so hard about separat ants and think more about nests. Ants act in the same way as cells in a higher level organism. The individual cells are stupid, but the organism (or nest) is intelligent. Many simple cells with many interactions between them behave as a brain. But a colony of ants is not a brain. It is actually more than that: it is an entire organism.

Nests and Organisms

As you read this, consider yourself. You are a vast collection of cells working in harmony to keep the collective alive. Your cells are in clamps, which we like to call organs. Each clamp is typically made up from specific cells specialised for a different task. For example, your liver cells are grouped together and do "liver things". Your skin cells are grouped together in a big sheet that covers you and protects you from bacteria and viruses as well as keeping you cool (or warm), generating certain essential chemicals from sunlight and so on. Your brain cells are grouped inside that big cavity behind your eyes, where they are currently thinking about themselves as they read this.

You are a community. Each of us is the result of co-operation between millions of cells. Your body does not have that many different types of cell (around 250 according to one recent estimate), but because there are rather a lot of them, and because they are organised in a rather clever way, they somehow act as the single organism.

Now think about an ant nest. Her nest is comprised of thousands of smaller, specialised things. Some maintain the temperature of the nest, others defend the nest from intruders, others go out and gather food, while inside the nest please small things looked after each other, remove the dead and help the new ones to grow - not cells, but ants.

Even the concept of reproduction seems strangely similar to that of a larger organism. Although the nest may be comprised of thousands of ants, they do not all reproduce. In fact all reproduction takes place via the queen. She generates haploid males which die immediately after reproduction - just like the sperm of a larger organism. She also generates chiploid queens, which are very reminicent of aches from a larger organism. So you can think of the queen as being the reproduction organ of the nest organism.

So "nest organisms" - or "superorganisms" if you want to use the original name, are rather clever things. But, you may have noticed that I have not really answered that difficult question I stupidly posed earlier: how can a colony of ants become clever? We know that the nest organism is clever whereas an ant is not, just as you are clever wearer someone selling your body is not - but how? Just what goes on when a group of stupid ants to something clever? The answer comes from an unlikely source: physics and chemistry. Its name is self-organisation.

pg 111

Self Organisation

The your ideas of self Organisation were not created with social insects in mind, and were they do help to explain a few things. The concept were constructed to explain some strange observations made in the world around us: weird patterns in rocks, highly regular structures of crystal growth, oscillating patterns in chemicals, or structures emerging suddenly at the certain temperature. These things looked as though a single entity was controlling them, designing them, but in reality they were organising themselves.

How do they do it? Well, there are quite a few different answers to this question. One common view is that self organising systems should be thought of as energy exchange systems. To use even more frightening terminology, self organising system should also be thermodynamically open. What all this means is that there should be a flow of energy through the system - that is, the system should be exchanging energy or mass with its environment. We can check that an ant nest does this: and sixpence energy as they move themselves and objects in their environment; they gain energy from food sources in their environment.

The trouble with these energy exchange systems is that they tend either to settle into a state of equilibrium ought to fly off into randomness. If the system is to prevented from settling into a stable state, it needs to be dynamic - undergoing continuous change. But if it is also to be prevented from becoming entirely random, that change should not become excessive. Because of this, it is often said that self-organisation lies on the boundary between order and disorder, or "on the edge of chaos".

As an example, consider water. If there is insufficient energy and change in the molecules of water, then it settles into equilibrium - that is, it solidifies into ice. But if there is too much energy and change, the molecules jiggle about randomly and you've got water. For selforganisation to occur - for example, those patterns of frost on the window or the delicate structure of snowflakes - we need something halfway between the two.

Okay, so we need energetic, snowy ants. But what has this to do with lots of stupid things becoming clever with the work together? Well, you are right to ask. Such concepts can be useful tools to help us think about selforganisation. However, thinking about being on the edge of chaos is not really explain anything about our ants right now. Instead of having to rely on exotic theories of mathematicians and computerscientists we have some more down-to-earth ideas, thought of by the researchers who actually work with social insects, and indeed by those who work with the digital equivalents inside our computers.

pg 114

The nest makes collective decisions - choices and plans that are beyond the capabilities of a single ant. The nest can solve problems. Nests solve the same problem every day, and many other similar problems too. Indeed, they solve this kind of problem so well that, we use digital equivalents in our computers to solve massively complicated scaled up versions of similar problems.

For now back to the point: the nest was intelligent. It made a choice and it also performed something that resembled planning. This happened because it did for important things.

First, it is used to multiple interactions.

Secondly, it used positive feedback.

Thirdly, it uses negative feedback.

Fourthly, it amplified fluctuations.

 

HOME      BOE     SAL     TEXTE