Genes and Other Things 1

Task 1: The paragraphs in the text below have been mixed up. With the other members of the group put them in the correct order in the table below.

A)  Some are useful and give the creature an advantage which allows it to have babies which are more likely to be successful. But this process is entirely accidental. This slow business of trying new body shapes and styles, some of which work and some of which don't, has been going on for as long as life. Perhaps you know about it. It's called evolution - the survival of the fittest.

B)    The nineteenth century naturalist Charles Darwin was the first to realise that all life is governed by this rule. He found that creatures did indeed adapt though he didn't know how because, in his time, people didn't know about genes. It turns out that genes can change. They don't always make perfect copies when a cell divides. Sometimes a mistake is made. This is called a mutation. Most mistakes are disasters - the organism dies.

C)    Our home planet is four thousand six hundred million years old. That's 4,600,000,000 years. And life has been around for most of that period. That's plenty of time to try out a system for making new life to replace old, and this works just about perfectly. What's more, very simple life forms - just single cells - long ago began to join together to make more complicated bodies with thousands or millions of cells. All these new types of life were natural experiments to see what worked and what didn't. Many didn't work and died out - they became extinct.

D)    Some worked for hundreds of millions of years like the dinosaurs, but still ended up extinct. New types of bodies - organisms - generally work when they happen to be in a part of the planet where there's plenty of food and few enemies. Too little food, nasty climate or vicious enemies spells disaster and means extinction unless an organism can adapt in some way. This is where genes come in.

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