400 Million Years of Ferns

Ferns are all leaf, all the time—no slow preparation for the momentous flower, no seduction of the insect. At the tips of young fronds, fiddleheads unfurl, fronds lengthen, leaflets appear and widen behind the unfurling tip like the widening wake behind a boat. My store-bought Boston fern, tended for years with no expertise, bears dazzling fronds that arch up, out, and over—a fountain of green.

Ferns were among the earliest plants with roots to dig deep for water and vascular stalks and stems to transport it throughout the plant. They were the first to grow arrays of hundreds of leaves. This was almost 400 million years ago. Earlier plants had lived entirely in the water, with no need for deep roots. On land, before the ferns, the first mossy plants, lacking roots or stems, could grow no higher than a few inches. Vascular tissue—tubes that conduct fluids, minerals, and gasses—changed everything. Ferns reached the height of trees. And today vascular systems circulate the red blood through us all.

Ferns emerged late in the Devonian Period, which lasted from 419 to 359 million years ago. About 30 million years prior to the Devonian, the first of Earth’s five mass extinctions took place. The climate cooled, water froze, glaciers grew, the sea level fell, coastal and ocean habitats disappeared. As the earth warmed again, carpets of moss sprang up along lakes and streams and bony, heavy-jawed fish swam in the seas. Then ferns and other plants became the first forests.

Devonian ferns wikimedia


Toward the end of the Devonian, the second mass extinction took place. It came in three pulses. Ocean species, including the heavy-jawed fish, disappeared. But land plants, including the ferns, were mostly spared. In fact, one theory  (bbc.com/earth/story) holds that the roots of the ferns and other plants broke through rocks and released nutrients into the lakes, rivers, and oceans. The nutrients fed huge blooms of algae which later died and decayed, taking up the oxygen that had kept the fish alive. Meanwhile, again, the ferns thrived.

Ferns proliferated in part because of how they propagated. Here they were—and are—old fashioned. Instead of reproducing via miniaturized plants embodied in seeds, ferns spread through spores, single cells released from the underside of the fronds. When the spores settle on moist soil, they grow a tiny intermediate plant that will provide the fertile start for the new fern. Spore propagation seems a complicated two-step process, but the lightness of the single-celled spores let them disperse on the wind and germinate on distant, moist soil.

Some days I gawk at a plant whose distinctive family features date back 400 million years. No other plant or animal that I see every day goes back almost to the start of life on land. The ancestors invented leaves and roots but kept the old method of reproducing.  They survived four mass extinctions, as well as the flowering plants that burst on the planet 125 million years ago and dominated the plant kingdom. Ferns watched the dinosaurs come and go. Today they regale us with tales of ancient climates and their durable adaptations.


Note: Among the sources on ferns, Don Lubin’s “Introduction to Ferns” is especially readable and informative for the general reader.


The Biology Of Suffering

“Where does suffering come from? Why do we suffer?” The questions open biologist Ursula Goodenough’s essay “The Biological Antecedents of Human Suffering” (in The Routledge Companion to Religion and Science (2012)). Through the ages, people have looked to religion for the answers, with no easy satisfaction. But under a biologist’s eye, the questions look more manageable.

Goodenough proposes two categories of suffering, the biological and the experienced. Biological suffering comes to all living things. Bacteria, plants, and people all seek out what they need—water, food, light—and withdraw from what will harm them—poisons, enemies. Any organism with too little of what it needs or too much of what will weaken it is struggling, under stress.

Durer_Revelation_Four_Riders (sciencemediacentre.co.nz)

The Four Horsemen of the Apocalypse by Albrecht Dürer  (sciencemediacentre.co.nz)

For animals with developed nervous systems, however, such suffering not only occurs biologically but is also experienced. The biological struggle announces itself through the nervous system. Vertebrates (with a backbone, head, and skeleton) carry neurons called nociceptors in their skin and internally in muscles, joints, and the gut. When nociceptors tell the brain that something is very wrong, the brain interprets the message as paina finger sliced with a knife,  a twisted ankle, sudden nausea. In addition, for humans—social, self-aware creatures that we are—the sources of such experienced pain include social and psychological feelings (envy; guilt) as well as bodily injury.

Fortunately, for most of the difficulties that organisms endure, antidotes are available. Organisms will move towards water if they need it, try to compensate for an injury, muster immune responses to fight infections, call a friend if they are lonely. Goodenough calls these corrective measures amelioration systems; they make things better.

But they don’t always feel good. Often we humans can feel them at work more sharply than the adversity that triggered them in the first place. Our noses get stuffed up during a cold not by the rhinovirus but because our immune system swells the sinus blood vessels in order to muster antibodies against the virus. We run an uncomfortable fever not directly because of an infection but because a higher body temperature strengthens the immune response.

Such amelioration systems are indispensable. To paraphrase Goodenough, organisms whose amelioration systems fail to cope with adversity will die. Organisms whose amelioration systems are inactive because they have all they need enjoy well-being. But it is organisms whose amelioration systems are at work “actively dealing with difficult circumstances” that are in a state of biological suffering.

Sometimes the suffering is not felt: “The food-deprived amoeba or the bacterium, the plant plunged in darkness or subject to a wound, pays the suffering price, but does not feel the price.” In other cases, for humans and other vertebrates, the price is acute pain. Pain alone won’t ameliorate a condition but calls attention to it—and may teach a lesson that brainy creatures can remember about what to do differently next time.

In still other cases, though, continuous or recurring pain is a scam. Chronic pain is “physical pain that is not obviously in the service of amelioration systems and is unresponsive to analgesics or other practices….Here we encounter an example of things gone awry.” With chronic pain, “Suffering has become uncoupled from resolution.”

Goodenough closes, “The long evolutionary view of suffering is that it is an inherent feature of life….[It] is part of the package, the price paid for the gift of being alive at all.” Up to a point, we knew this already—that at least some suffering goes with being alive. But Goodenough’s naturalism presents suffering in an earthly mode, with less mystery and without guilt.  Still, we are left to reckon with the irony that what we suffer from are the workings of the body’s methods of repair and renewal.

These highlights amount to only a partial summary of Goodenough’s rich essay, which is here at Google Books.


Darwin and the Buddha

The teachings of Charles Darwin and Gautama Buddha are worlds apart. Yet their descriptions of life bear similarities to each other and even interlock in ways that expand my view of each.  I’ll focus this comparison on  On the Origin of Species and the Dhammapada, a widely read collection of the Buddha’s sayings.

The differences are straightforward enough. Darwin’s eye was mainly on the past. In Origins, he observed the characteristics of successive generations of plants and animals—except for humans, whose evolution he discussed in other books—to show how natural selection and fertility served as the sources of the variation of species.

The Buddha, on the other hand, focused on humans, on the pain of our disappointments and the ease that disciplined renunciations could bring. And in contrast to Darwin’s focus on ancestry, the Buddha’s eye was on the future, on each person’s potential path forward out of suffering. Finally, while Darwinian evolution moved on inexorably, the Buddha convinced his followers that their future was in their own hands, that if they turned inward to grasp the nature of change and expectation, they could calm their cravings.

Yet beneath these distinct differences, both thinker followed a logic built from the same pieces.



First, for both Darwin and the Buddha, the struggles of ordinary life make up the starting point for the consequences and possibilities that followed. As different as their two works are, taken together they rest on the premise that for humans, animals, and plants alike, life is stressful, sometimes dangerous, and often unpredictable. Whether in a plant stunted by inadequate sunlight or a woman in conflict between family and her career, it is everyday obstacles and threats that drive the changes that the thinkers explored.

Such changes consisted of a series of steps, the other great commonality between their views. For Darwin, the steps were those small, random variations which, if they benefited an organism consistently, took their place among its inherited traits. Though each step was small, the end result could be a new, better-adapted species. For the Buddha, the steps consisted of a discipline in correct understanding, the extinguishing of selfish desires, and future rebirths. As they were in Darwinian evolution, the steps to enlightenment took time but led to relief from pain.

Combined, these variations on the themes of struggle, gradual change, and final resolution offer a rich vision: living things experience conditions that are not easily or perfectly satisfied, but the future offers steps from pain towards peace, though not necessarily within an individual’s lifetime. In place of a deity to oversee the the fate of living things, both men saw a reality in which ordinary life and an organism’s response to it were sufficient to drive changes sooner or later.

I and most people and animals tend to fix our gaze on those satisfactions and dangers that we see a relatively short distance ahead—the state of our income, our health, our children, our security, predictable weather, unpredictable disasters. I wonder what it was like to have the mindset of Darwin and Buddha, tuned to long spans of steady transition in which a being’s every moment is a step towards elsewhere.


My thanks to Elaine Smith for her assistance.