Monday, 28 July 2008

The Great Wormtown Spade Disaster (Part 1)

Author's note: The story below is my attempt to put some of the core concepts of Evolution into terms that are accessible to a wide audience. I'd hope it could be read and understood by anyone from the age of 10 without patronising anyone over the age of 12... a tall order maybe. For anyone interested in what it all means, I've listed some of the concepts touched on in their scientific terms at the end.

Wormtown isn’t much to look at. Given that its inhabitants lack eyes, perhaps that does not matter. It consists of little more than some earth in a field Somewhere. It is inhabited of course by some Worms, who would have given Wormtown its name, if they had a language or indeed any means to speak it. The soil is warm, rarely disturbed and the general conditions are mild. The worms themselves are a simple bunch. They are microscopic and quite smooth. They have just three small grasping stubs on each side of their long bodies to aid their movement through the soil. And of course they also have the bits needed for eating and reproducing. Although the reader might have difficulty telling the difference, there are both male and female worms. The females lay eggs in large communal nurseries and their chosen male partners fertilise them. The process is a little messy though, and sometimes the wrong eggs get fertilized by accident (or on purpose if a male worm in question is a bit of a creep). Other inhabitants of the area include smaller animals called Foods and bigger ones called Eaters. The Worms, called Smoothies because of their appearance, eat the Foods when they can catch them and sometimes fall prey themselves to the Eaters. Aside from eating and mating, the Smoothies do little more than move around through the soil. Sometimes the Smoothies burrow to the surface and feel the Sun, which is rather painful and makes them burrow back down again. This state of affairs persists for a Very Long Time.
Every now and again a Special Child is born. Sometimes they have brightly a short body or coloured skin (the Smoothies can’t see this but the Foods and Eaters sure can). Sometimes they have no graspers or a stomach that won’t work. Special Children almost always die early. The ones that do survive pass on their dangerous characteristics to some of their children who themselves, sadly, die early.
One day, a worm is born with strange graspers. Instead of short and blunt graspers made toughened skin, this strange child has longer, sharper graspers. Of course, Worms have previously been born with bigger or smaller graspers than usual, but these differences never seem to help much. This sharpness is new and strange and the child is named Sharpie. Being simple souls (and also blind), the worms don’t hold this peculiar look against Sharpie, not that they could do much about her if they did. Still though, Sharpie finds her life a bit more awkward than the other worms. Her pointy horns make movement more difficult, which makes Foods harder to catch. Luckily, Foods are quite plentiful in Wormtown and so Sharpie survives, albeit struggling somewhat, and even lives to find a free-thinking mate and have children of her own.
Most of Sharpie’s kids are quite normal-looking Smoothies. But a few, males and females alike, have the same strange horns as their mother. Sharpie herself dies rather young as a result of her impaired movement, but having had a number of children, the reader can feel satisfied that Sharpie has made her mark on the world. So it is that a generation of Sharpies goes out into Wormtown. And they fair reasonably well. Sharpies still struggle to catch Foods when compared to Smoothies, just has their mother did, but their sharp horns give them a new edge that only now becomes clear; Eaters are less afraid to eat them! Sharpies and Smoothies mate frequently, producing litters that are a mixture of Sharpies and Smoothies. As the generations pass, this means that Sharpies are born that are distantly related enough to mate with each other without making the reader feel vaguely uncomfortable.
The years pass and the population of Wormtown settles into an equilibrium, a balance of sorts. So long as there are plenty of Foods, both the Smoothies and Sharpies can survive, though at different success rates. As long as there are predators attacking both, the Sharpies can partially overcome their disadvantage when it comes to getting Foods. And so at any one time, about one in ten citizens of Wormtown is a Sharpie. They form a sort of racial minority who thankfully don’t suffer from much by way of discrimination, if only because the Worms are rather lacking in the brains required for one to be properly ignorant.
The idyllic, peaceful and now quite diverse community of Wormtown is about to face disaster.

Part 2: In Which Disaster Happens

To learn more: Google these terms: Introduction to Evolution, Speciation, Mutation, Genetic Drift, Natural Selection, Habitat Fragmentation, Peripatric Speciation.

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