Why Biodiversity Matters for Planetary Health

On a planetary level, humans resemble a pioneer species. In a few generations, we have multiplied prolifically. The rapid growth resembles the high-entropy-production phase of a new ecosystem. But if we are truly the r species of a global ecosystem, we do not know what that ecosystem is-it has not existed on Earth before. Becoming stewards of the Earth is a noble calling. But the more rapidly a species proliferates, the higher the probability that viruses, bacteria, fungi, and other animals will treat that species as a succulent gradient to be devoured.

Mature ecosystems and adult organisms have lower entropy production per unit weight although they process more energy (and produce more entropy) overall. Mature ecosystems and adults peak in size. Children run higher temperatures, corresponding to higher growth rates, but over time they become adults who require fewer calories per unit mass. No longer growing, they funnel energy into continuing operations; they use energy more efficiently.

Stress, however, can send an organism or ecosystem reeling back to earlier, less efficient modes of managing energy flow. Consider forest fires, destructive but not fatal. The large trees of late-stage forest ecosystems are vulnerable to winds and pests.

Mammalian body temperature is not constant. It changes with time of day, state of digestion, and sleep-activity cycles. Although not in equilib-rium, mammal physiology has many “steady-state-like” aspects, especially when the animal is not quickly growing. The variability of metabolism reflects nature’s supplementation of ancient with more energy-efficient metabolic modes.

Pesticide, radiation, and oil cause ecosystems to malfunction. Such systems are impaired. They no longer capture as much energy or build the intricate structures that they once did. They no longer expand along natural successional trajectories toward maturity.

We bipedal primates known as humans have an ancient, deep, mutually reinforcing relationship with forests and trees. Comparative anatomy provides such a wealth of circumstantial evidence as to amount to proof that our ancestors, assuming their body shape was remotely like our own, lived for millions of years amid the branches. This is perhaps why we sometimes start upon falling asleep–an ancient survival reflex for arboreal mammals hiding in relative safety but in danger of falling and breaking bones on the forest floor. So, too, we seem to be hardwired to appreciate the bright colors, sweet tastes, and fruity smells that represent for prosimians, simians, and apes rich reserves of fructose -fruit sugar that can power primate perception and locomotion, tree-going bodies and brains.

Today, we still surround ourselves with wood, often living in effect in modified tree houses, and the sight and smell of fresh wood is calming. Paper products, moreover, form a crucial part of modern civilization, from toilet paper and paper towels to books, newsletters, newspapers, and mag-azines. In some places the rate of deforestation has reached alarming rates, and the example of humanity, which has historically slashed and burned wooded areas to make room for agricultural grains, is an ominous warning of technological power unchecked by long-term planning. Deserts that many people take to be natural and inevitable, such as the Sahara and much of the Middle East, have at least been exacerbated, and may have been caused, by agriculture and overgrazing.

Like the proverbial fish who, surrounded by water, does not see the clear environment that sustains it, so too it is tempting for people to ignore the importance of woodlands not just in the past, but in the present and future. Wooded areas temperate, subtropical, and tropical-are interesting not only for their beauty, their harboring of as-yet-undiscovered pharmaceuticals, and the intrinsic nostalgia conferred by their status as humanity’s primeval natural homeland.

Although a common distinction made between plants and animals is the alleged immobility of the former, this is not true. Both plants and animals are formed of nucleated cells with chromosomes that exhibit internal cell streaming. The common ancestry between plants and animals is suggested by ginkgo trees and mosses, which produce swimming sperm cells nearly identical in appearance to animal sperm, except that they have heads that are green with chloroplasts.

Human populations expand and dramatically change planetary energy budgets. What is good for rapidly growing human populations is not necessarily good for larger ecosystems. Nietzsche said the world is beautiful, but it has a pox called man. Thermodynamically, this is true insofar as our global activities have impaired life’s most highly developed systems of gradient breakdown.

Surface temperatures of Earth depend greatly on ecosystems. Clear-cut areas have surface temperatures near 50°C, whereas mature four-hundred-year-old forests have surface temperatures of 25°C. As large parts of the equatorial and high-latitude rain forests are being cut and burned, we may expect a serious attenuation of the water cycle that works through trees to produce light- and heat-reflecting clouds over forest canopies.

Today an estimated 10 to 15 million species exist, although more than 99% of all those that ever existed are now gone. There has been an increase in species, a lush branching, over evolutionary time. We interpret this de facto species rise over time to mean that during evolution new species were selected for as new pathways for energy capture and degradation developed.

Each new species represents, like a new leaf on a tree or a new business in the global economy, a new pathway for energy capture, storage, and degradation. New species find underutilized gradients and habitats, and make them their own. Over geologic time the steady march toward greater species diversity has occasionally been seriously upset. Nonetheless, life has bounced back, replenishing the global genome each time. If the past is prologue, then recovery from the present mass extinction, precipitated by human destruction of large animals and climax forest ecosystems, is also likely. Whether humans survive to see such a recovery, let alone enable it, is an open question.

The human-caused planetary decline in species diversity is disturbing.

Source : Into the Cool: Energy Flow, Thermodynamics, and Life by Eric D. Schneider, Dorion Sagan

Goodreads : https://www.goodreads.com/book/show/52737.Into_the_Cool

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