Rethinking Our Relationship to Nature, 1920–1959 97
DOCUMENT 82: H. V. Harlan and M. L. Martini on the Loss of
Genetic Diversity (1936)Plant and animal breeding and selection has been practiced for thousands of years. While this was done on a
limited scale, there continued to be tremendous variation between crops grown in disparate communities in far-
flung places. However, as international trade and communications increased, a worldwide preference for a small
number of grain species developed and some local species began to disappear.
H. V. Harlan, an agronomist, and M. L. Martini, a botanist, were working in the Department of
Agriculture’s Bureau of Plant Industry when they recognized that the widespread use of certain popular
varieties of cereal grains posed a threat to genetic diversity. Harlan and Martini had many concerns about
the loss of genetic resources and ancient, local plant varieties, including the effect of this loss on the
development of new species.
Within the next few decades, as scientists began to understand the relationship between biodiversity and
ecosystem functioning, the wider ramifications of this loss of biodiversity became evident. Toward the end
of the twentieth century, a contentious global debate arose over the benefits versus the drawbacks of the
widespread use of genetically modified seed for a handful of strains of corn, rice and other crops that had been
developed by a few large agribusinesses [see Documents151 and 155].In the great laboratory of Asia, Europe,
and Africa, unguided barley breeding has been
going on for thousands of years. Types with-
out number have arisen over an enormous area.
The better ones have survived. Many of the sur-
viving types are old. Spikes from Egyptian ruins
can often be matched with ones still growing
in the basins along the Nile. The Egypt of the
Pyramids, however, is probably recent in the
history of barley.... In the hinterlands of Asia
there were probably barley fields when man was
young.
The progenies of these fields with all their
surviving variations constitute the world’s
priceless reservoir of germ plasm. It has
waited through long centuries. Unfortunately,
from the breeder’s standpoint, it is now being
imperiled. Historically, the tribes of Asia have
not been overfriendly. Trade and commerce of
a sort have always existed. They have existed,
however, on a scale so small that agriculture
has been little affected. Modern communi-
cation is a real threat. A hundred years ago,
when the grain crop of north Africa failed, theof the biome—the habitat factors in the widest
sense. Though the organisms may claim our pri-
mary interest, when we are trying to think fun-
damentally we cannot separate them from their
special environment, with which they form one
physical system.
It is the systems so formed which, from the
point of view of the ecologist, are the basic units
of nature on the face of the earth. Our natural
human prejudices force us to consider the organ-
isms (in the sense of the biologist) as the most
important parts of these systems, but certainly
the inorganic “factors” are also parts—there
could be no systems without them, and there is
constant interchange of the most various kinds
within each system, not only between the organ-
isms but between the organic and the inorganic.
These ecosystems, as we may call them, are of
the most various kinds and sizes. They form one
category of the multitudinous physical systems
of the universe, which range from the universe
down to the atom.
Source: “The Use and Abuse of Vegetational Concepts
and Terms,” Ecology 16 (1935): pp. 295-99, in Carolyn
Merchant, Major Problems in American Environmental
History (Lexington, MA: Heath, 1992), p. 451.