Renewed esteem for a former marine enemy

Recently the NSW Department of Primary Industries put out a press release, proudly announcing the development at its Cronulla Fisheries Centre of artificial wombs to assist with breeding larger numbers of grey nurse sharks.

Archimedes was fascinated that this $600,000 project was duly reported and discussed in the media with a minimum of public outcry. He can remember the days when grey nurse sharks were cast as villains who preyed on unsuspecting swimmers. As such they were to be shunned, feared and killed.

We know better now. The modern image of the shark is of a top predator and endangered species, whose potential disappearance from the marine ecosystem could lead to nasty imbalances further down the food chain. And, as it turns out, grey nurses are supposedly not particularly aggressive.

In nature, things are often not as they seem superficially. If there’s one thing the development of the biological sciences—ecology, biochemistry, genetics—has taught us over the past 50 years, it’s how bewildering complex organisms and their interactions are.

At the level of the shark and the snake, we seem to have absorbed that lesson. They are not necessarily evil animals, and are an important, functional part of the environment. We now also know that simple solutions, such as the blanket use of broad spectrum insecticides and antibiotics, can have a negative impact and that introducing exotic creatures, such as rabbits, foxes and cane toads to the Australian environment, is a mistake.

Simple systems belie beguiling comlexities of natureBut we still have great difficulty coming to terms with biological complexity. We don’t handle it at all well. We seem to hunger and thirst for a simpler world. Take our attitude to diet, for instance.

It seems that every second week the advice as to what is good for you and what is bad for you changes. And often the same dietary ingredient is labelled both good and bad at the same time on the basis of different studies.

If we stop to think about it, this is not surprising. Most foods and drinks consist not just of one ingredient, but of hundreds of different compounds, many of which can interact in different ways with the hundreds of thousands of different molecules which make up our bodies. So, the stimulant caffeine is only one compound in coffee, which also includes a range of cancer-preventing antioxidants, and many other biologically-active substances besides. Further, whether the balance of ingredients in any one food or drink does you good or ill may well depend on your own genetic make-up.

A blatant example of this dietary complexity was outlined in a recent editorial in the Sunday Age on the push by the Salvation Army to have cancer warning labels pasted on bottles of alcohol. The editorial writer pointed out that while alcohol did indeed raise the risk of cancer, for the moderate drinker the cancer risk from alcohol was still low, far lower than smoking, sun exposure or lack of exercise. On the other hand, recent studies suggest that a low level of consumption actually has a benefit in protecting against heart disease.

At another level, we all know that in moderation alcohol can play a useful role as a social lubricant, but in excess it leads to social disruption. It all depends on who you are, and how much you drink.

Simple systems belie beguiling comlexities of natureIn the face of these kinds of contradictions, all we can do is learn more about the complex interaction between diet and disease, and play the percentages. The most recent research suggests that exercise is almost universally good, smoking is almost universally bad, and most other things we take into our bodies are somewhere in between.

That’s typical of almost all biological systems, including human societies. They’re a good deal more complex than we take them for—and it’s rare that a simple, black and white solution will solve a problem. Often, the failure to acknowledge the complex links in natural systems just makes matters worse.

Many would argue, for instance, that the lasting legacy of imposing the simple solution of “Prohibition” of alcohol in the US was a boost in endemic organised crime, and that the “War on Drugs” seems to be proceeding down much the same path.

The crude application of brute force doesn’t necessarily solve political and economic problems either—as the Soviets found in Afghanistan, and the “Coalition of the Willing” is finding in Iraq. Antibiotics did not turn out to be a “magic bullet” to treat infectious diseases forever. Nor are we likely to find a simple solution to climate change, be it a wholesale swing into renewable energy, or nuclear energy.

Maybe the greatest long-term spin-off of research in the biological and medical sciences will be learning about how to work with the complex structures exemplified by biological systems.



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