Authors:
Historic Era:
Historic Theme:
Subject:
February 1963 | Volume 14, Issue 2
Authors:
Historic Era:
Historic Theme:
Subject:
February 1963 | Volume 14, Issue 2
In the spring of 1847 Thomas Woodcock, president of the Natural History Society of Brooklyn, New York, received from England a crate containing several pairs of small, dingy birds. He released them in a city park. None survived the following winter. Woodcock repeated his experiment with a similar lack of success each of the following three or four springs. In either 1851 or 1852 his persistence was rewarded, and Passer domesticus , the house sparrow, joined Rattus norvegicus , the house rat, Mus musculus , the house mouse, and Homo sapiens , the house builder, in the ranks of America’s major settlers.
All four of these immigrant species continue to prosper here despite the way the first three annoy the fourth. Many other varieties of once-foreign fauna and flora also thrive in the hospitable hemisphere to which they have come.
Many animal interchanges took place in the distant past between Siberia and Alaska via the land bridge which repeatedly has risen above and sunk below the waters of Bering Strait. Paleontologists have found that some animals that long seemed typically western hemisphere types—such as bison and black bears—actually may have done most of their evolving in the eastern hemisphere and crossed the bridge only a few million years ago. Others, such as horses and camels, were absent here when Columbus arrived but had originated here and traveled to the Old World late in the course of their development. In the last few hundred centuries the Indians have been the only notable new form of life to cross the bridge. (The dogs they brought with them from Siberia, apparently their only companions, were scarcely different from native wolves and coyotes.)
The Indians settled into inconspicuous niches throughout most of the hemisphere and provided minimum competition for native species. Ever since 1492, however, most immigrants have been the opposite of inconspicuous and uncompetitive. The hemispheric balance of nature still gyrates dizzily in response to them.
By far the most obvious in impact are the domesticated plants that now blanket millions of acres. With only a few notable exceptions all the cereals, fruits, and table vegetables commonly grown in this hemisphere originated in Asia, Africa, or Europe and have arrived here since Columbus. The Admiral himself brought along a wide variety of seeds on his second voyage, and most of the other explorers did the same. Jacques Cartier, for instance, reported that on his 1541 voyage up the St. Lawrence River, “We sowed seeds of our country, as cabbages, turnips, lettuces and others, which grew and sprung up out of the ground in eight days.”
Oddly, the better an immigrant plant has thrived here, the lower the U.S. human immigration quota is likely to be for the region from which the plant originated. Among non-native cereal grains, for instance, by far the most important is wheat, which originated in the Near