July 9, 2007
ants save the planet
Reading Theodore Roosevelt's "The Winning of the West", one comes across this argument for the moral necessity of the American settlers' conquest of the territory long occupied by their human brethren:
All men of sane and wholesome thought must dismiss with impatient contempt the plea that these continents should be reserved for the use of scattered savage tribes, whose life was but a few degrees less meaningless, squalid, and ferocious than that of the wild beasts with whom they held joint ownership.
Disregard for a moment the picture of the be-spectacled amateur historian and future president astride a noble equine beast in a rakish sombrero and spurs, brandishing a shotgun--and think about the wild beasts, specifically, ants.
(Evaluating alternative hypotheses for the early evolution and diversification of ants. Sean G. Brady, Ted R. Schultz, Brian L. Fisher, and Philip S. Ward, 2006)
Ants are the world's most diverse and ecologically dominant eusocial [altruistic] organisms.
They also evolved on the planet long before human-like mammals. They were here probably 180 million years before us, in fact. Over that time we were basically a statistical question-mark waiting for our genetic entry into earth ecology. More than a hundred million years before ants came on the scene the whole insect family had already incorporated metamorphosis into its trick-bag of survival tools, plants had adapted to northern and southern hemispheric conditions, and angiosperms had arrived giving plants the ability to flower. It makes the invention of the plow look a bit puny.
By the time humans began walking upright, everything else on earth looked essentially the way it does now. With a few exceptions. There have been at least five major mass extinctions before humans arrived, the most recent, 65 million years ago, was likely caused by an errant asteroid hitting the earth mid-latitude and wiping out the biggest mammals on the planet, dinosaurs, and over half the plants.
Here's how that event looked to scientists, based on fossil and other evidence: after the asteroid hit it took about ten years for the sulphuric acid released into the atmosphere to dissipate, reducing the amount of sunlight to about 10-20 percent of normal during that time. Most photosynthetic plant life was wiped out, but fungi and ferns gradually reappeared. Polar dinosaurs, able to withstand the cold temperatures brought on by lack of sunlight, still perished, indicating the lack of food, rather than lack of heat, killed them.
The other four major extinctions had variable causes, probable among them glaciation, volcanic eruptions, and supernova explosions. The main earth extinction events have occurred about every 60 to 100 million years. There is no rhyme nor reason to this frequency. But the next extinction may be very different from the previous ones. There is speculation by some, and in fact a majority of biologists believe that we are, in fact, in the middle of another extinction event. For it's probable cause we need look no further than in our bathroom mirrors.
While the "big five" earth extinctions happened over a long geologic timescale, taking millions of years to play out, the current extinction event is happening very rapidly - in tens and thousands of years. In the last fifty years, the rate of species extinction has accelerated to exceed the rate during the previous five extinction events. Estimates today are that up to 140,000 species disappear every year. The eminent biologist E.O. Wilson predicts that in the next 100 years, human activity could cause the extinction of over half the species living today.
And who will be left standing (or rooting) after the current extinction event? Well, in previous extinctions the die-out of species was to some extent selective, affecting mostly those species and genera that were least able to cope with the conditions brought on by the extinction event--cold temperatures or lack of sunlight (leading to lack of vegetation and thus lack of food). Rare, localized, and specialized species are probably most at risk of extinction, as shown by fossil studies of extinction events and their aftermath. Widespread or adaptable species are likely to survive.
One of the features of the most widespread species is social behavior. Social insects, for instance, account for more than half of all the world's insect "biomass" (a measure of total living weight versus total numbers of individuals). But only about 13,000 species out of a total of 750,000 insect species are social. Social insects - ants, wasps, bees - are the most common insects. All ants are not only social, they are eusocial - meaning they employ division of labor in reproduction, generations overlap, and they cooperate in the care and protection of young. Eusociality is a genetic trait, passed on from one generation of ants to the next. Worker ants who do not reproduce (are not able to reproduce) yet pass on more of their genes by caring for their sister ants with whom they share 80% of their genes than they would by having their own offspring, who would carry only 50% of their genes.
So, my point was? Just that the beasts of the earth may, by virtue of their longevity and social behavior, be better equipped than humans to sustain life on the planet. That the "scattered savage tribes" who lived here before us "civilized" humans may have been better equipped to sustain life on the planet, as hunter-gatherers instead of as industrial agriculturists. And any little ecological niche that you can protect from destruction, even the ones in your own backyard, are worthy of saving.
I will try to remember that the next time I am standing in a swarm of ants when turning the compost, or worrying about the paper wasp nest in the garage. Making or reserving a place for the bees or wasps or ants may be the best thing we can do for our planet.
