I want to argue that, for all of life’s lease on the planet up to today, we, we living things, have lived with frontiers. Our ecosystems behaved as if there was an out there and a round here, a system in an environment. We know this by looking at the sorts of adaptations living things have. They show, broadly, organisms reacting with heuristics to the immediacy of their environment. It is true that there are some adaptations that show a subtlety that betrays close coupling—many interactions on coral reefs and symbioses of all sorts show this. But for most of the time, most organisms behave as if the world is loosely connected, that there is fuzziness and slop in the world, and that, to survive, organisms need to focus on just getting through the moment.

We can see that this is a sensible, efficient response to a physically dominated world, where grand biogeochemical cycles and forcing factors are more geo than bio. But as life evolved and radiated and became more complex, one might expect that evolution would turn its hand to how to survive in a world made complex by other living things. And here we see something curious. It is true that complexity—the emergence of complex adaptive systems—does encourage some closer coupling. Every naturalist’s notebook is full of such wonders, and every diver and birdwatcher has seen them. But it is also true that heuristics—rules of thumb—account for much if not most of the interactions between living things. It seems that evolution demands that living things adapt frugally to the emerging complexity of the world, using the sorts of heuristics and work-arounds they used in earlier, simpler times. Even though living things are faced with the emergence of complexity, they are constrained in their response by such prosaic things as history, mutation rates and generation times.

There seem to be two canonical but conflicting rules that govern the way in which living things respond to the world around them. And neither insists that the complexity of the world be acknowledged in any deep way. The first is that, for most practical purposes, what happens next is, to a first approximation, a simple extrapolation of what just happened. Even complex non-linear processes look just like simple linear ones when taken one little step at a time (this, after all, is the key discovery of the calculus). The second is, for living things in a world made complex by other living things, after a few steps, something else will happen. Thus there is no need to get too involved adapting to (that is, predicting) the impact of some complex long term process when it could be overtaken at any time by the Next Big Thing.

By and large, evolutionary success for living things has meant coping with the monotony of endless moments as well as the occasional surprise. This is the law of the frontier, and reflects the fact that adaptation through tight couplings is found mostly within organisms—the things we call physiology—or within cells—the things we call biochemistry. The couplings between organisms are generally much looser and those between ecosystems looser still. The world, as a system, is really a bunch of loosely connected subsystems, where the connections, for adaptational purposes, are more or less indistinguishable from the random buffetings of the environment coming through the frontier.

We see this in the dynamics of all ecosystems on earth. This includes, of course, the dynamics of human societies. Those systems that behave as if they have a frontier can adapt with simple here and now heuristics and succeed, whether they are the Huns invading Europe, the English colonising the new worlds, some weed invading a rangeland, or just a barnacle on the shore facing tides and storms. What makes today different is that man ‘knits up the ravelled sleave’ of the world through all his activities, and it is just about complete. Globalisation is just a fancy term for closely connecting the world’s economies, and hence its societies, and this has more or less reached the point where we can speak of a world economy as a single functioning entity. In parallel with this, our economic exploitation of the world’s natural ecosystems is now more or less complete. And economic exploitation means close connection. There are really no wild, unexploited places left. The last coral reefs, seamounts, deserts and taigas are getting locked in as I speak. There are no frontiers.

We see the evidence all around us, even if we focus on the epiphenomena and not the underlying structural change in the way the world works. We see SARS, blackouts, the Asian financial bust, ballast water, the ozone hole, global warming, and even bushfires connected to red tides as a list of phenomena instead of symptoms of the emergence of a singularity: the fully connected world. We, we living things, now live in a world system where the balance of effective adaptational strategies has shifted decisively and forever from heuristics to what we might call symbioses—the sorts of strategies that evolution favors in closely connected systems, the ones we see today inside cells and organisms, and between symbiots. No doubt evolution will sort this out over the next several hundred million years, but in the meantime: ‘Houston, we have a problem’.