The naturalist's dilemma

kw: book reviews, nonfiction, natural history, population genetics

A young scientist's education is primarily an exercise in becoming expert at reductionism. This is a necessity. The skills of keenly observing the minutiae of nature are a necessary foundation for all scientific inquiry. Most youngsters like to take things apart, and a good gift for an inquisitive pre-teen is a mechanical alarm clock, to be taken apart, and reassembled. Getting it back together so it works properly is a satisfying accomplishment.

But reductionism is just the beginning of education. In the natural world, there are few things you can disassemble, then reassemble properly. This goes without saying for living things and living systems (ecologies), but even many inorganic systems simply can't be reproduced by human art, and this will always be so.

As a scientist matures, his or her view must broaden, and the syntheses that result from scientific study must become more comprehensive. It is one thing to study one class of enzymes, or some few species of fishes, or the minerals that compose certain ore bodies. It is quite another to fit the enzymes into a metabolism, the fish into an ecology, or the ore body into the creation of a continental province.

I have always considered naturalists to be the most fortunate scientists. Just to be any good at their trade, they need the gifts of a good mind and a humble attitude. They gain the pleasure of a more comprehensive education than most. Then they are privileged to work in a variety of interesting, if not always pleasant, surroundings. Books I read by naturalists frequently mention the beauties of the environments that they study. Finally, they gather and synthesize the data and information needed to learn what is really going on and how we humans fit into nature; for it is certain that we remain a part of the natural world, for all our efforts to insulate ourselves from it.

John and Mary Theberge are a naturalist couple, scientists whose honeymoon now spans a generation or more. How fortunate to do work you love, with the person you love! They say it takes five to ten years to become an expert in one's field. It takes another ten or twenty to begin to see "the big picture". The Theberges have had thirty years of observing natural systems, and in my view, are accomplished experts in the ecological view of Earth. Their new book The Ptarmigan's Dilemma: An Exploration Into How Life Organizes and Supports Itself presents the best of their work as a series of studies in population dynamics.

The book is a bit bigger than most, and it took me a while to get through. It rewards careful reading. The population of cells that produce a tissue, the tissues that make up the body of a plant or animal, the assemblage of living things that blanket a mountain side or jungle landscape, and domain after domain of such assemblages that become the ecology of a continent, all have to solve the same problem: capture energy so as to carry out the processes of life and avoid extinction or extermination.

In one statement that resonates with me, the authors write, "[P]opulations are either regulated directly by the environment, or indirectly by internal mechanisms that the environment triggers. In either case, population control is necessity for biological order on Earth." Loss of population control leads to cancer in a body, to decimation of a landscape by a weed species, or to the growing environmental disaster we call modern civilization.

We humans like to think we control nature, but are not under nature's control. If our population were merely the nearly seven billion of us, that would be one thing. But worldwide, we tend about 1.4 billion cattle; that is just one "domestic" species. Those cattle outweigh humanity by 30%. Around the world, we also tend sheep, llamas, elephants, emus, salmon and catfish, which probably weigh in at a similar total mass to the cattle.

The authors take a little more moderate view of climate warming than many. They are alarmed by it, but not alarmist about it. It is, as they state, the largest-scale experiment yet to be conducted by the human race. It will certainly lead to many fascinating studies of how populations around the globe respond to a climatic shift. For example, migrating bird species have had several thousand years to get used to the current interglacial warm period. How soon will they adapt to the new climate?

I wonder how many generations it took the Red Knot (a bird that flies from South America to the Arctic, with a stopover along the Mid-Atlantic shore) to adapt to the great shift in biome productivity that occurred 11,000 years ago when the latest ice age switched off in less than a century? Will they have to adapt even more quickly to the northward biome shift we are forcing right now? Will the Horseshoe Crabs, upon whose eggs the Red Knots feed, change the beaches on which they spawn? In a generation or two, we will know, but we cannot predict what will happen, or how.

For most of the history of Earth, the changes have been more gradual. One sea turtle (I think it is the Loggerhead) has had 100 million years to adapt to the widening Atlantic, and now swims half an ocean to lay eggs on a small cluster of mid-Atlantic islands. When that turtle species first evolved, the swim was just a few miles.

In chapter after chapter, recounting the stories of their charges, the authors help us understand the dilemmas all creatures face to send forth their offspring, hostages to an uncertain future. The Ptarmigan of the title lives on the edge of freezing, and the mother birds make constantly shifting choices for their chicks. The chicks are precocious, and must get their own food from birth. But in a cold springtime, they chill quickly, and the mother calls them to brood under her warm feathers. The authors undertook a study to determine just how close the chicks come to freezing, and how close they come to starving as the weather cools. They found there is still a bit of margin in favor of the chicks; the mother birds don't nest so far north that they'd be unable to raise their chicks.

Another point of interest arose when they studied coop-raised Rock Ptarmigans, a control group for their work. Wild Ptarmigans don't have a gall bladder. Autopsy studies of coop-raised birds showed that they did have gall bladders. It is an example of epigenetics, in this case an organ that is potentially there, but is not grown unless the environment demands it. There was a lot more fat in the coop-raised birds' diet than a wild bird gets, so they grew a gall bladder to cope with the different diet. Epigenetics explains a lot of seemingly hidden features that are expressed only when an environmental shift requires their expression. It is a side point to this book's thesis, but is an area of much study as scientists seek to refine our understanding of natural selection.

In one chapter, the authors ask, what about Humans? Are we still subject to nature's laws? We most certainly are. While we have tried to produce a global perpetual motion machine, we will never be able to extract energy that simply isn't there. What is the world's carrying capacity for Homo sapiens? It is likely that we have already exceeded it. Food may not be the crucial factor. I have been predicting for several years that we will soon enter an era of Water Wars.

Liberal democratic political philosophy is based on the principle, the greatest good for the greatest number. Right now, there is great good for a relative few, a growing "middle class" that is at least comfortable, but an even more rapidly growing underclass for whom the term "misery index" is a sad irony. We measure their penury, but do little about it. There is a reason that a few of the "thirdest" of third world countries have life expectancies not much over forty years. Nature cannot be denied. If the numbers of humans continues to increase, the proportion of them that live with little misery will decrease, perhaps to zero. We are the first species with the cleverness to get ourselves into such a dilemma. Will we have the intelligence to get ourselves out? If we don't, nature will do it for us, but at a much greater cost in human suffering.

I cannot end without recalling the many more lyrical portions of the book. The authors have been privileged to work in some very beautiful landscapes, which typically means landscapes with little human imprint. There aren't many left. I pray that the remaining years of humanity's residence on Earth will be marked by increasingly wise use of the resources nature provides, and of the ecological services (such as fresh water and oxygen) that we consume. For a truly livable Earth, we must find a way to achieve a smaller "human footprint", so we can not only live well without ruining all of Earth, but have the opportunity to experience some of the lovely, wild places that have been wisely kept from being "improved" by short-sighted human ambition.