Essential to life

June 24, 1992

By Tracy Sorensen

If we lost the long-footed potoroo, mallee fowl and bilby, it would be very sad, but life would surely go on. If there are between 10 million and 30 million species on this planet, the loss of these and a few others, give or take a hundred thousand, would hardly matter in the long term, would it?

It would. Preserving biodiversity is not so much about rescuing those with the softest fur and prettiest feathers, but ultimately about preserving life itself.

In an article in the May 13 Los Angeles Times, environmental scientist Donella H. Meadows notes that the entire evolutionary history of the planet is contained in the DNA of the world's living organisms. The destruction of genetic information through species extinction is the natural equivalent of burning libraries and killing intellectuals.

The wealth of genetic information in the world today has been selected over billions of years to fit the ever-changing necessities of the planet, writes Meadows. "As the Earth's atmosphere filled with oxygen, as land masses drifted apart, as humans invented agriculture and altered the land, there were lurking within individuals pieces of genetic code that allowed them to defend against or take advantage of the changes."

Biodiversity is thus both a genetic storehouse and the key to future adaptations. Preserving it involves not just protecting the various species but preserving populations within species. This is important because it is the variability between individuals in a species — some roses smell sweeter than others, for example — which allows for adaptation (survival through change).

Human-induced extinctions, says Meadows, represent an "unparallelled catastrophe", up there with global warming and the hole in the ozone layer. "It's a fair guess that at the rate we're destroying habitat, especially but not exclusively in the tropics, we're pushing to extinction about one species every hour ... Earth has not seen a spasm of extinctions like this for 65 million years".

Meadows illustrates biodiversity's centrality to the survival of humanity, and to all life on Earth, like this: "Suppose you were assigned to turn every bit of dead organic matter, from fallen leaves to urban garbage to road kills, into nutrients that feed new life. Even if you knew how, what would it cost? A host of bacteria, moulds, mites and worms do it for free. If they ever stopped, all life would stop."

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