28 December 2016
Bald Eagle vs. Chicken, Who's winning on evolutionary terms?
[C]onsider how to answer the following question: which bird, species A or species B, has been more successful in the evolutionary process of natural selection? If you are like us, we suspect that your first thought would be to compare the relative numbers of the two birds. With a little more time, you might decide that you would also like to know about relative sizes since at equilibrium the environment could probably sustain fewer large birds than small birds. Controlling for habitat needs you would seem to have a simple, but fairly accurate, measurement process.
Now let us make the question a little more concrete: which bird, the bald eagle or the chicken, has been more successful in the evolutionary process of natural selection? Shall we do the math? There are approximately 70,000 bald eagles in North America, a number that is up considerably in recent years following the bald eagle's near extinction. It is a little harder to know just how many chickens there are in this country at any given moment, but our rough calculations put the number somewhere between 1.75 and 2 billion. That means that for every bald eagle there are twenty to thirty thousand chickens.
Even discounting the figure slightly to take into account the eagle's larger size and habitat requirements, the numbers are clear: the standard farm chicken is the bald eagle's evolutionary superior. But that finding seems absurd. We know the bald eagle as our national bird, a symbol of strength and power. Eagles are extremely well adapted for survival in nature, given their superb flying, hunting, and nest-building abilities. For centuries, bald eagles thrived, and according to one history, they may have once numbered half a million .
“They existed along the Atlantic from Labrador to the tip of south Florida, and along the Pacific from Baja California to Alaska. They inhabited every large river and concentration of lakes within North America. They nested in forty-five of the lower forty-eight states. One researcher estimated an eagle nest for every mile of shore along Chesapeake Bay. They congregated on the lower Hudson, and were extremely abundant along the coast of Maine.”
So then we have missed something. In determining that chickens are more fit than eagles to withstand nature's trials and challenges, we have ignored critical situational influences. Why are there so many more chickens than eagles? The more obvious and correct explanation is that humans value chickens in a way that they have not valued bald eagles.
Indeed, there are robust markets in both chickens and eggs. According to a recent industry-sponsored survey, Americans consume, on average, eighty-one pounds of chicken per year—a figure that appears to be going up and that represents “the highest per capita consumption of any of the major meats.” They also consume approximately 260 eggs per year. Unsurprisingly, market pressures ensure that there are many chickens alive at any given moment.
Well, if bald eagles are so fit, why did they nearly go extinct and why are there still so few of them? The following history of the bald eagle helps to shed light on a different sort of situational influence on the bald eagles' stature than is imagined in any idealized, unrealistic "natural selection" script.
“There is no single cause for the decline in the bald eagle population. When Europeans first arrived on this continent, bald eagles were fairly common. As the human population grew, the eagle population declined. The food supplies for eagles decreased, because the people hunted and fished over a broad area. Essentially, eagles and humans competed for the same food, and humans, with weapons at their disposal, had the advantage. As the human population expanded westward, the natural habitat of the eagles was destroyed, leaving them fewer places to nest and hunt, which caused the population of bald eagles to decline sharply by the late 1800s.
“By the 1930s, people became aware of the diminishing bald eagle population, and in 1940 the Bald Eagle Act was passed. This reduced the harassment by humans, and eagle populations began to recover. However, at the same time DDT and other pesticides began to be widely used. Pesticides sprayed on plants were eaten by small animals, which were later consumed by birds of prey. The DDT poison harmed both the adult birds and the eggs that they laid....
“More than 100,000 bald eagles were killed in Alaska from 1917 to 1953. Alaskan salmon fisherm[e]n feared they were a threat to the salmon population.”
According to that history, the threat to eagles was not that they were ill-equipped to survive in nature, but that their success as a species did not appear to serve the interests of humans. Indeed, the eagles competed with human interests, including commercial interests.
As a result, the grand, and once ubiquitous, bald eagle was pushed toward extinction. Meanwhile, chickens were raised in huge numbers to meet the increasing demand for their eggs and meat. The relative success of chickens over bald eagles, then, has little to do with the survival of the fittest and a lot to do with "the survival of the tastiest" or "the survival of the profittest."
In light of that competition among birds, look again at how … scholars tend to measure the success of various schools of thought. … [A]cademics generally assume that they are competing in some neutral tournament wherein ideas evolve and good ideas become more prominent while bad ideas disappear. According to this view, the tournament benefits the outside world by generating and announcing the winning ideas, which are then relied upon to help make effective and desirable policy. Thus, when some ideas are more commonly accepted, are attracting larger audiences and are having more influence … , the assumption is often that those ideas, like the bald eagle, soar above their ground-bound, clucking competitors.
But here is the problem: the competition among ideas may have much in common with the imagined competition between chickens and eagles. That is, in both contexts there appear to be very significant demand-side factors that help determine which ideas will be most prevalent and seemingly most successful. For reasons that we have already highlighted, the "winners" will be those ideas that are valuable to the more influential participants on the demand-side of the marketplace—specifically, pro-commercial interests.
from The Situation:
An introduction to the situational character, critical realism, power economics, and deep capture.
By Jon Hanson and David Yosifon
University of Pennsylvania Law Review, Vol. 152, p. 129, 2003-2004