What if all the cars in the world were the same? – Why it pays to be different
Imagine if every car in the world was exactly the same – the same make, the same model, the same parts. Imagine you had no choice at all.
And imagine if every car in the world was fitted with the same faulty part; and that all those faulty parts gave out at the same time. Every car in the world would break down simultaneously. The result would be utter chaos.
It won’t happen. Not because cars don’t break down, but because there’s so many different types of cars, and so many different types of parts, that if one part is faulty it will only ever put a few cars off the road at once.
The same is true with plants and animals. Or at least it used to be true, until people came along. A drought, a fire, a flood or a new disease would have a hard job wiping out everything alive. Because all living things are a little bit different from each other, some will perish while others won’t. By chance some have genes which make them vulnerable to a new threat, others have genes which help them survive it.
In agriculture it’s different. A paddock of wheat is a paddock of plants more or less identical to each other. For thousands of years farmers have chosen the best wheat seeds, from the best wheat plants, to breed from. A paddock sown with a variety of wheat is like a paddock sown with identical twins. A new disease or a new pest could kill the lot.
In fact just such an event had a profound influence on Australian history. In Ireland farmers used to depend on a single variety of potato. But in 1845 and 1846 Irish potatoes were suddenly attacked by a new fungal disease, called potato blight, which invaded from America. The result was an horrific famine, which killed more than a million people, and drove a flood of new migrants to Australia.
Agricultural breeding is an arms race, with pests and scientists each battling to stay a jump ahead of each other. Pests constantly evolve new ways to attack crops and livestock, researchers constantly look for new genes to make plants and animals resistant.
There’s only one place these new genes can come from – from nature. Out there in the wild world there are anything up to 30 million species of living things. And within each species there are uncountable different varieties just as in humans some people have crinkly hair, some straight. When scientists want a new gene to fight disease or pests in agriculture, they look for it in nature.
When scientists want a new drug, they also look for it in nature. Six of the top 20 drugs in the world came originally from chemicals found in living things, and so did 18 of the 43 new drugs brought onto the world market in 1993. Even the common drug aspirin, taken by most Australians, was first found in a plant called meadowsweet.
But the world is changing. People are clearing away the wild places – the forests, the grasslands, the wetlands – and replacing them with farms and cities. Every day species, varieties and entire ecosystems are vanishing forever. One estimate says that 10,000 species are being sent extinct each year. The truth is no-one really knows. What we do know is that the huge variety of nature is being thinned out, and fast. In scientific terms, we are losing our “biodiversity”.
Australian plants are as important as any others. Our native species include many close relatives of important world crops – like soybeans, mung beans and cotton –
which can be cross-bred with agricultural plants to make crops more drought-resistant, more salt-tolerant, higher-yielding, more resistant to pests and diseases. The new technologies of genetic engineering means even genes from plants and animals which aren’t related at all can be used. And just as the traditional European herbal remedy meadowsweet gave us aspirin, Australian plants might contain new drugs – some of which might have been used by Aborigines.
Indeed, Australia is recognised by scientists as one of the world’s richest biodiversity countries. It is one of 12 nations which has been declared to be “megadiverse”, because it contains so many species and varieties which are found nowhere else.
But you can’t conserve biodiversity in a zoo. All you can hope to save in zoos are a few of the big, cute animals. Conserving biodiversity is everyone’s responsibility. The CSIRO is now mounting a major research effort to learn more about Australia’s unique biological heritage, and how best to preserve it.
Last year, all around the world, the global Convention on Biological Diversity cam into force. It is an international agreement, negotiated under the umbrella of the United Nations, to conserve biodiversity. Australia has joined it, so have more than 75 other countries. In line with the Convention, Australia’s Federal, State and Territory
Governments are working on a joint national strategy to conserve Australia’s biodiversity.
Biodiversidade ou diversidade biológica é a diversidade da natureza viva. Desde 1986, o termo e conceito têm adquirido largo uso entre biólogos, ambientalistas, líderes políticos e cidadãos informados no mundo todo. Este uso coincidiu com o aumento da preocupação com a extinção, observado nas últimas décadas do século XX.
Pode ser definida como a variedade e a variabilidade existente entre os organismos vivos e as complexidades ecológicas nas quais elas ocorrem. Ela pode ser entendida como uma associação de vários componentes hierárquicos: ecossistema, comunidade, espécies, populações e genes em uma área definida. A biodiversidade varia com as diferentes regiões ecológicas, sendo maior nas regiões tropicais do que nos climas temperados.