I’d tried getting into The Diversity of Life twice before — 2018 or 2019 I think — but could not persevere beyond a few dozen pages. I wasn’t ready then for the kind of dense biology content that E.O.Wilson (the famous Harvard naturalist, known for his research on ants) was trying to communicate to lay audiences. In August last year — the beginning of my two semester teaching break — I picked up the book again. This time I sailed comfortably through. I read it over many months, savoring the details. Interesting how content that is so bumpy at one time can feel so seamless at another. (There was also an odd coincidence: I was about three quarters through the book when I heard of Wilson’s passing at age 92.)
The Diversity of Life exudes a kind of mystery that I found enticing. It was as if I’d stepped into a strange new world, not unlike Alice’s Wonderland or Tolkien’s Middle Earth. Except that Wilson’s world — populated with the innumerable lifeforms of our planet and the ecosystems they inhabit — is very real of course. (Innumerable quite literally: for no one knows how many species there are on earth.) In the excerpt below, one of my favorites in the book, Wilson illustrates that to fathom the diversity of life one cannot think of space in “ordinary Euclidean dimensions”. Rather one has to think in “fractal dimensions”, with microscopically smaller ecosystems nestled within larger ones:
…picture in your mind a large beetle 50 millimeters long, living on the side of a tree. As it walks around the trunk, browsing on lichens and fungi, it measures a trunk circumference of 5 meters. But it cannot take account of the much smaller world at its feet. The beetle is only scarcely aware of the many dips and hollows in the bark, only a millimeter across. In that irregularity live other species of beetles small enough to make it home. They exist in an entirely different scale of space. To them irregularities are not trivial. As they crawl down the sides of the crevices and up again, the circumference of the tree trunk is about ten times what it is for the giant beetle, which knows nothing of the tiny crevices. The surface of the trunk is a hundred times greater for the small beetles, the square of the difference in the circumference perceived by them and that perceived by the big beetle. The disparity translates into more niches. Different crevices contain their own regimes of humidity and temperature and a variety of combinations of algae and fungi on which insects can feed. Hence small beetles have many more dwelling places and foods on which they can specialize, and as a result correspondingly larger number of species can evolve.
Let us descend deeper into the microscopic. At the feet of the small beetles are still smaller crevices and patches of algae and fungi too narrow for them to enter. Living there, however, are the smallest of all insects together with armored oribatid mites, measuring under a millimeter in length. A close scan of the surface geometry reveals that the species of this diminutive fauna live as if the surface of the trunk were a hundred times or more greater than the surface embraced by beetles the next size up, and thousands of times greater than the titan beetle looming over the whole ensemble. Finally, the tiny insects and mites stand on grains of sand lodged in algal films and the rhizoids of mosses, and on a single grain of sand may grow colonies of ten or more species of bacteria.
[…]
In the fractal world, an entire ecosystem can exist in the plumage of a bird. Among the prominent organisms living in that peculiar environment are feather mites, spidery organisms apparently subsisting on oily secretions and cellular detritus. Individuals are so small and territorial that they can spend most of their lives on part of one feather. Each species is specialized on a feather type and feather position, such as the outer quill of a primary feather, on the vane of a body contour feather, and so on through what to feather mites is the equivalent of a forest of trees and shrubs. A single parrot species, the green conure of Mexico, is host to as many as thirty species, each with four life stages, making a total of over a hundred life forms. Each of these forms in turn has its own preferred site and pattern and behavior.
Wilson’s prose, as you can tell, is dense with analytical detail. But it also has a certain meditative, immersive quality. The tree-trunk and plumage microcosms which might — to our ordinary senses — have seemed familiar, uninteresting even, are now revealed to contain hidden worlds. There’s a large number of such engrossing passages in the book, ranging widely in space, time and context: from the massive volcanic explosion in Krakatoa (1883) to the great extinctions in earth’s deep history, to dispatches from dwindling biodiversity hot spots around the world. The effect is an expansive, richly textured portrait of life on earth, how it survived the cataclysms of the past, and how it is — once again — experiencing an accelerated decline, a sixth great extinction. Hope to post more excerpts from the book.