By Henry Lappen Gazette Contributing Writer
One day last summer, I watched something small and brown fall to the ground. Not sure if I was seeing a leaf or a moth, I knelt to have a closer look. Sure enough, it was a moth—one so perfectly adapted in size and color and in its flying behavior as to imitate a dead leaflet from a honey locust or some such tree. I’m sure it must fool many a predator, whether dragonfly or phoebe, and continue to survive and propagate its species.
This past year, however, it must also have had other adaptive traits to have survived the “predatory” weather. It must have been able to withstand drought.
You may have noticed a dearth of insects last summer and fall. The chorus of crickets and katydids was noticeably quieter. And the firefly show was very short-lived. It usually lasts into mid-August. Last year, the flashing was over before the end of July. And so it went with moths, ants, wasps, even mosquitoes (ahhh!); with spiders, toads, snakes and swallows, all of which eat these insects; and with hawks, raccoons, coyotes and fishers, which eat those predators. Plants, too, were affected: Fewer leaves, fewer flowers and fewer seeds, which meant fewer rabbits and deer, and on through the food web.
Evolution has two ways of working. It happens slowly, day by day, as some life forms carry traits that favor survival in certain circumstances, and the animals or plants carrying them live and reproduce. My moth with its tricky flight pattern is one of these.
But evolution also happens abruptly and to the extreme, sometimes even with the rapid disappearance of whole species or ecosystems. Think severe droughts and tsunamis. Think epidemics, volcanic eruptions, or meteor strikes. And, of course, there’s global warming or, more generally, climate change.
When a catastrophic event hits a species, usually not every individual perishes. Some escape by their own abilities, others by luck. They may have an adaptation that gives them a particular survival advantage.
While crow populations plummeted from West Nile virus these past few years, some survived and are reproducing, increasing their species’ numbers again. When the plague struck Europe in the Middle Ages, some humans were similarly immune. Nowadays we can hope that at least some small brown bats have such an adaptation, an inheritable trait that will allow them to survive the current “white nose syndrome” epidemic that is devastating the species.
Or some may just be in the right place at the right time. When Mount Vesuvius buried Pompeii, some people happened to be away from the city and lived to tell about it. Some animals got buried by debris that protected them from intense heat and falling lava, and were able to dig themselves out when conditions improved.
Even in more global crises when an entire species or even a family of species disappears, some life forms persist. Whether by luck or genetic predisposition, whatever survives and finds a new habitat will repopulate and evolve to fill the void left by the extinctions.
This combination of quick and slow change, adaptation and luck, has led to the incredible diversity of life on earth. From mushrooms to whales, from bacteria to cacti, from scorpions to humans, life has survived and diversified over hundreds of millions of years—through every manner of drought, flood, temperature extreme, earthquake, cosmic radiation and countless other environmental changes. Human-induced global warming is just one more event.
Life will survive. It may not resemble its current forms. Much of the beauty and richness that we treasure will be lost. But believe it, in time—time beyond the scope of human beings—evolution will prevail and find a new balance. And life will be even richer. Most likely, we humans won’t be a part of it. I wonder if my moth will.
Henry Lappen is an environmental educator who performs the show “A Passion for Birds.” His website is www.HenryLappen.com.
Earth Matters, written by staff and associates of the Hitchcock Center for the Environment at 525 South Pleasant St., Amherst, appears every other week. For more information, call 413-256-6006, or write to us.Click here to return to full list of Earth Matters articles.