Societies Seen As Ecosystems

Something I have wanted to write about for a long time is the uncanny way in which human societies are analogous to ecosystems.  Furthermore, the roles within these societies grow and change and wink out—just like species in different ecosystems do–and yet they hew to certain broad generalized templates over time. This seems so self-evident to me that almost doesn’t need to be talked about, and yet when I do talk about it, I realize that it is difficult to explain comprehensively.

There are many ecosystems—like rainforest, arid scrubland, deep ocean bottom, steppe, or coral reef.  The creatures in these ecosystems are designed by long, long generations of competition and gradual mutation to use the resources of the ecosystem to survive.  Thus a sea anemone eats plankton that the current wafts into its tentacles…and then a clownfish evolves to live protected in the stinging tentacles and look after the anemone…and then a sea turtle evolves which eats anemones and so on.  The larger ecosystems are connected too.  For example, the pelagic ocean depths engender huge quantities of plankton which wafts onto the reef.

There are many niches in ecosystems—like arboreal fruit gatherer, lurking swamp predator, or planktonic browser.  Convergent evolution causes the shapes of creatures adapted to these roles to take on many similar characteristics:  thus arboreal fruit eaters (whether they be iguanas, tarsiers, or cockatoos) have cunning grips, small agile bodies for precise balance, & acute depth perception; planktonic browsers have huge mouths, filter membranes/apparatuses, and a shape build to conserve energy; and reef building organisms are sessile with grabby arms and a calcium carbonate skeleton they can retreat into (even if they are not corals).

Of course there are always generalists like raccoons or rats or pigeons which have a number of useful traits that allow them to flourish in a city, a field, or a forest, or wherever…but truly complicated ecosystems engender flamboyant specialists like frogs that live in bromeliads or saber hummingbirds with beaks longer than the rest of the bird’s body.

A jungle might support a few tribes of generalized hunter gatherers (who literally live off the rainforest in the manner of jaguars and toucans), but humans build our own jungles which we call cities.  In the city there are niches for jaguar people who take what they want and for toucan people who are colorful and pick fruit from the tops of trees that others can’t even get to.  Let’s imagine them respectively as business magnates and art curators. Resources are plentiful in cities.  They arrive in raw forms from other places like farms, mines, or forests and then are processed and synthesized by the city which creates secondary and tertiary tiers of specialists who live off of individual refinement steps which might not even exist elsewhere.

A farm town might have farmers, millers, bakers, bailiffs, carters, and a few thieves, as well as a single baron and a mayor. The city has grain merchants, food factory workers, pastry chefs, bicycle police, teamsters, catburglars, legions of dukes, and a whole vast city hall bureaucracy (and all the other roles in between).

As the niche change through time so to the roles change, but there are underlying similarities. Farriers, lectors, and lamplighters have died away but we now need mechanics, voiceover actors, and electric engineers. Some jobs, like bricklayer or toymaker endure for thousands of years.  Some, like wartime airplane detector exist only for a particular moment in time (after airplanes but before radar).

If you look at society from a distance you can see how technological and social changes mirror the changes of evolution. Cartwrights generally are replaced by automakers (although there were probably not may individuals who made that career change).  Indeed, our manufactured objects themselves illustrate this change (as you can see by looking at a history book of cars and watching fins and fenders grow and shrink, even as the overall cars become lighter, faster, and safer).

Just as the natural world is more dynamic, beautiful, and robust when there are may sorts of environment with many different creatures, human society is more prosperous when it has lots of different sorts of settings including places of enormous diversity with all sorts of specialized roles.  The interchange is complicated in the human world.  How many theatrical make-up artists can Iowa support? Yet the collagen in the makeup came from Iowa farms…and perhaps the makeup artist herself (and maybe the actors she works on too) originally came to Broadway from little towns in the corn belt.

This metaphor is useful in looking at the arc of history (which is really hard to comprehend from a human-length temporal perspective).  Additionally, it ties the world of natural history/paleontology together into a seamless narrative with the world of history/sociology (we will get back to this in later posts).  It becomes easier to see how thoroughly we humans are part of the natural world—we are sophisticated colony primates not some aberration from outside biology (or clockwork children made by a crazy god). Beyond these vast perspectives of deep time, biology, and macro-economics, however, it is useful to look at society as interlocking ecosystems because it reminds us to be more careful of one another since we need one another.

There can be no city without the countryside! And who would farmers sell their barley to without cities? (and where would rural hospitals get doctors or malls get new fashions)?  Likewise the farmland needs the forest. The fishing village needs the ocean. In this red-blue era where people from the country and the city apparently despise each other (!) we need to recall it is a false distinction. Everyone needs each other.  The world is a web.  If you touch one thread the whole thing vibrates. And it is changing so fast that we little spiders and flies must also change so swiftly that it is barely possible to figure out who is preying upon whom anymore.  We will come back to this concept, but right now take a look around you and squint.  If the clerks, and stockbrokers and stockboys don’t start to seem more like termites and tigers and tapirs…if the dairymaids and cows don’t seem like ants and caryatids, well let me know. I’ll write it all down a different way.  But I will be surprised if you don’t see it.

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Armored Mammals: the Cingulata order

The Giant Armadillo (Priodontes maximus)

We boldly continue armor week with an overview of the magnificent armadillo family.  This order of armored mammals (Cingulata) is more diverse than any other sort of armored mammals–outshining even the scaled pangolins. Today the only living members of the Cingulata order are the armadillo family (a successful group consisting of more than 20 living species) but the armadillos’ extinct cousins were once far more widespread and bizarre.  These relatives included the pampatheres–long plantigrade browsing creatures covered in banded armor who roamed the continent from one end to the other.  Even more impressive were the glyptodonts, massive tank-like creatures bigger than a compact car.

A fossil glyptodon, fossil pamphathere, and armadillo skeleton (in the far right corner)

The Cingulata order is part of the superorder Xenarthra. Separated from all other placental mammals for over 100 million years (due to South America’s unique isolation after the breakup of the southern supercontinent Gondwana), xenarthrans evolved in different directions from other mammals. The unique challenges and opportunities of their island continent resulted in bony domed giants like the pampatheres and glyptodonts, both of which are characterized by tortoise-like body armor composed of bone segments (osteoderms).  The glyptodonts were unlike tortoises in that they could not draw their head beneath their shells: instead their heads were protected by bony caps atop their skulls. The largest glyptodonts could grow to 4 metres long, 1.5 metres high and have a mass of 3 tons (Ferrebeekeeper has already written about the smallest known Cingulata species—the pink fairy armadillo, which can still be found living in the central dry lands of Argentina).

Glyptodon

Thanks to convergent evolution the herbivorous glyptodonts resembled other armored giants like cryptodire turtles and ankylosaurs.  One species of glyptodont, Doedicurus clavicaudatus, even had a heavy spiked tail (although it is unclear whether this was used against predators or to compete for territory and mates).

Doedicurus clavicaudatus

When the first members of the Cingulata order emerged in the Myocene, the top predators of South America were giant running predatory birds–the Phorusrhacidae, which resembled giant dashing eagles up to 3.2 metres (10 ft) high.  The glyptodonts, pampatheres, and armadillos outlasted these terror birds and they then outlasted the carnivorous metatherian mammals (with terrible saber teeth) which followed.  When the Isthmus of Panama connected South America with North America (and therefore with an entirely new universe of ultra-competitive mammals), the armored cingulatans competed just fine with the newcomers.  Some glyptodonts and pamphatheres wandered up through Central America and found new homes in North America.  The armadillos are still there.  However at the end of the last ice-age, a new African species arrived and brought a devastating and final end to the glyptodonts, the pampatheres, and most of the armadillos. But even this newly arrived predator seemed impressed by the greatest of armored mammals.  An Argentine anthropologist even reports discovering a site twenty leagues from Buenos Aires where early human hunters had used glyptodont shells as dwelling places.

Human Hunters Stalk a Glyptodon (Heinrich Harder)