A Debt to Ponds

by William H. Amos, Vermont, USA

 It is surprising how small a part of life is taken up by meaningful moments, most of them over before they start. Yet they cast a light upon the future, and those reaching the future are unforgettable.

Anonymous


 I was slow putting books away in my scarred lift-top desk and was the last pupil to leave the seventh grade classroom. I walked down the corridor into the rest of my life.

 As I passed the upper school laboratory, the sole occupant, a science teacher, invited me to see what he had under a microscope in a drop of pond water. I had never looked through a microscope, but squinting down the brass tube I watched a tiny creature, a one-celled protozoan I learned later, feeding in its infinitesimal world. Rhythmically beating hairs around its bell-shaped body produced a vortex in the surrounding water, drawing in particles it ate or rejected. How could such a tiny creature be so complex, exercise such flawless coordination and discrimination? Did every pond contain such wonders? The scene welded some synaptic gap deep in my brain. Frozen in time, the exact image remains.

 Carl Sagan said, “A passion for discovery is hardwired. It’s something we do for its own sake, but it brings rewards...” My own wiring suddenly activated, the only reward I sought was making a microscope from chipped discarded lenses, held in place with modeling clay within a cardboard tube. Search as I might, its cloudy glass could not reveal the marvels of pond life I sought. But my father watched and at Christmas, a few weeks away, a small folding microscope gleamed under the Christmas pine. Nothing else mattered. Years beyond have been spent peering at microcosms impossible to dream. Satisfying one’s curiosity disregards peril, and for me opened a door to lifelong exploration—in ponds, the sea, and the macrocosm beyond.

 Exploratory behavior is deeply ingrained in the animal world. Accomplishments are based upon experience. We and all creatures search for nourishment, a safe retreat, our own kind, and when a particular goal is reached, the seeking stops. Some investigate for the sake of novelty alone without an obvious goal, pursuing sensory exploration of new situations. Discovery itself may be the sole reward; learning has intrinsic value.

 An animal encountering an unfamiliar object in familiar surroundings finds out as much about it as possible. If an animal is satiated, it may store a discovered morsel away, or at least remember where it is when hunger strikes. Exploring new territory, some animals mark the region as “theirs” with glandular secretions, and remember the boundaries.

 Experimenting with new opportunities enhances survival and becomes a permanent part of behavior. How else did a clan of monkeys on a Japanese island learn to wash yams free of sand? Or an Egyptian kite learn to crack an egg by dropping a rock on it? When a cat investigates an open paper bag, its desire to learn is immediate and potentially rewarding—could a mouse be hiding inside? Exploration satisfies interest, but deprive an animal of opportunity to relieve its curiosity and an incapacitated individual results.

 How deep into the animal world can we go? Ponds harbor a little flatworm, Dugesia, existing near the lowest evolutionary rung of the multicellular ladder. Challenge one of these uncomplicated creatures by putting it in a flooded dish with a single morsel of food. The worm moves slowly, its simple head swaying back and forth, “tasting” the water. Little by little it moves in ever-narrowing circles as it searches for an increasing concentration of taste particles, triumphantly finally reaching the tidbit. It’s a stretch to call this satisfying curiosity, but a search began for something of value and concluded with a reward.

 Dugesia’s brain is extraordinarily simple, but in essence no different than ours—it serves the senses, and it learns through experience. Exploring an elementary maze, eventually the worm reduces its errors until it makes the correct choice every time. The more new circuits that are established in a brain (ours included), the more successfully a creature responds to challenges in unfamiliar situations. Dugesia can’t adapt what it has learned in the dish to life in a pond, but when returned to its native habitat, for a while it may turn more frequently to the right (what it learned), than to the left.

 We share with animals an appetite for discovery. Peering through a microscope in youth wasn’t my earliest exploratory behavior, but it was the first to lay out a path I’ve followed ever since.

  The poet William Wordsworth lamented, “A primrose by a river’s brim, a yellow primrose was to him, and it was nothing more.”

 He was describing a non-observer, a person lacking in wonder. Of course, we might be overwhelmed by senses responding to a deluge of stimuli and collapse into quivering confusion and sensory burnout. Fortunately we are physiologically and neurologically insulated against such short-circuiting. Wordsworth took aim at one who neglected both senses and mind.

 I became a biologist. Tucked away deeply and permanently is the conviction that the living world is wondrous and in the end incomprehensible, even as modern science unveils previously enigmatic elements in nature’s edifice. There is more than pure science in hungering after truth.

 An inquiring mind can be addled by the immensity and complexity of populations in a very small volume of water. My garden pools hold only a few hundred gallons. From them, I examine a tiny bit of root cut from an aquatic plant. To this sliver are attached thousands of microscopic creatures and algae. There are two dozen such plants in the pools, each bearing several roots a few inches long. Then there is the pool’s bottom and sides thickly coated with detritus and life. Every submerged surface is crowded with minuscule plants and animals. Not a speck is left uninhabited .

 Imagine this Lilliputian world is Times Square crowded with human revelers on New Year’s Eve. Dump into the throng every plant from miles of Amazonian rain forest, and every creature from every zoo. Animals and people scramble over one another and shimmy up and down the trees. Look down upon a single intersection with its teeming masses and attempt to identify every living thing. With a flick of your line of sight, move to another intersection where the same concentrated activity takes place with different players. On a lesser scale this is what I see when I move a microscope slide containing a few drops of pond water from one scene to the next. Different in magnitude—identical bewilderment.

 It’s no good guessing numbers. Any spot in pool or pond invites a journey into wonder. Tangles of emerald algae; rotifers spinning vortices; nematodes coiling and uncoiling like watch springs; long-necked protozoans swaying like graceful swans; some diatoms stacked like railroad ties, others flowing like streamlined boats; ciliated cells tumbling; amebas dragging their sculptured “houses.”

 There is too much to see. The teeming transient population tells our own lives are equally ephemeral. Yet all are part of a continuum bordering on the immortal. Perhaps this is why I installed a garden pool in the first place. It helps me remember my place.

© 2001 William H. Amos
 

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Published in the  October 2001 edition of Micscape Magazine.

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