In G.K Chesterton's well known 'Father Brown' stories, he suggested that a good method of getting into a house unobserved was to be a postman. In other words, if you don't want to draw attention to yourself, then make yourself inconspicuous. A good place to hide is in a crowd.
In fact, there are basically two methods of hiding things that you want hidden. One way is to make them difficult to see - camouflage; the other is to make them difficult to pick out from the crowd - confusion. Likewise, there are similar tactics in protection. You can adopt the Fort Knox principle, and surround the valuables with heavy duty and expensive barriers; or you can avoid drawing attention to the valuables - hiding in a crowd again. Fish gather together in shoals because that gives them the best chance of not being eaten by a bigger fish. One snag of being a very big fish, is that its difficult to gather in large numbers - ask the whales.
When I first came across Richard Dawkins references to germ line DNA, I was immediately puzzled by something - wasn't this stuff very susceptible to attack? If a virus, or some other opportunistic vector, can insert its DNA into the germ line, then it gets a free ride for a very long time; maybe as long as the species (that the DNA codes for) survives. This stuff is the crown jewels; or to a software engineer, it's the master source code.
Straight away, in a flash of characteristic brilliance, (well, OK, fairly obvious really) I perceived the answer. This is why nature is so profligate with its sperm. If a vector wants to attack the germ line, its got an awful lot of targets to chose from - trees in the forests again. Chances of success are small, even with a lot of vectors hanging around.
In another flash, I saw the snag with this argument. Why, then is there only one egg? The perceptive among you will see that I have already provided the answer. Evolution has come up with two answers to the problem - lots of cheap little sperm, and one big expensive egg. The human egg has amazingly complex protection mechanisms - as soon as one sperm sneaks through the egg wall, the entire wall structure changes in a flash to keep out any competitors. Presumably this kind of complex defence is also pretty good at keeping out unwanted intruders. But complex defence systems don't come cheap, like Fort Knox.
Dawkins and others have already explored this cheap/expensive scenario to explain why the sexes have differentiated in this fashion. Evolution tends to drive the mechanics to both ends of the solution space. As far as I have read (I'm strictly an amateur in this field), no one has suggested that this separation is also a defence mechanism - but I expect someone has, somewhere. But just in case, I thought I'd pen this little piece and post it.
Next Essay |
Back to List of Essays |
Back to Home Page |