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Flight Lines: With time, everything changes and adapts

The song sparrow (Melospiza melodia) is one of the most variable birds in America with 24 different subspecies recognized by scientists. This individual, photographed in Oregon, contrasts sharply with the subspecies adapted to our area.

Portuguese explorer Ferdinand Magellan first described the native people near the southern tip of South America - an area he named Tierra del Fuego - in 1520 during his historic circumnavigation of the world (historic note: Magellan didn't finish the trip, he was killed by natives in what is now the Philippines. Only one vessel from his three-ship fleet completed the three year journey back to Spain). His and other early navigators' accounts of encounters with indigenous Fuegians leave readers in wonder. How did these people live in this cold, harsh, windswept piece of earth wearing little to no clothing? Despite our claims on cold tolerance here in North Dakota, I would wager most of us would be dead of hypothermia in a matter of days if not hours were we to face the rigors of Tierra del Fuego naked.

Virtually every living organism adapts, over time, to its changing environment. Everything from the tiniest virus to the largest animal survives by changing and adapting. If separated by geography and enough time, the "changers" may eventually become so distinct from their former kind to become separate species.

I spent several months in Nevada a few years ago and came to appreciate what geographical separation can do to organisms. Believe it or not Nevada claims over 300 named mountain ranges. Although some are quite small, most are separated from one another by vast swaths of dry inhospitable terrain, creating what scientists call "sky islands." A chipmunk, say, is not going to leave one mountain range, cross miles of desert, and climb another. Thus, over time chipmunks on separate mountain ranges, begin to display characteristics slightly different than the other.

It was Charles Darwin (who, by the way, also wrote of the Fuegians in 1835 while on his famous trip aboard the HMS Beagle) who noticed something quite curious among the finches he found among the various islands of the Galapagos. Upon examining the collected specimens, it was determined the group made up as many as 15 separate species. It's very likely each species derived from a single ancestor on these geologically young islands. Exposed to slightly different environmental pressures, slightly different microclimates, slightly different elevations, and slightly different food sources, each island produced a different version of the finch.

The flu shot we get each year is a cocktail of three different viruses determined to offer the best chance to combat a disease which kills tens of thousands of people every year. One of the frustrating aspects of this group of viruses is their ability to mutate, to change. The Centers for Disease Control spends a lot of our money every year chasing the latest version of this slippery ever-changing virus.

Brown bears are found in various locations across the northern hemisphere. Grizzlies, in fact, are a subspecies of brown bear. But for hunters, the Kodiak bear represents the ultimate brown bear hunt. It is easily the largest subspecies and lives only on a few islands in southwest Alaska. What favorable environmental conditions have allowed this particular subspecies to achieve such size is mostly a matter of conjecture. Yet, over time, this change has indeed occurred. (A recent study shows Kodiak bears may be more closely related to polar bears than brown bears).

This brings us back to the original subject and a question. Was it merely their upbringing or were the native Fuegians somehow physiologically adapted to the harsh climate? I've never read anyone's attempt at addressing this question but it wouldn't surprise me if a degree of adaptation had taken place. If every living organism changes to fit its environment over time, surely Homo sapiens can too. I don't know how many generations it would take North Dakotans to acclimate to Tierra del Fuego's climate. Maybe fewer than most. As for me, I'll take wool pants and a North Face parka please.