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428
THE LIFE SCIENCES
tinents to immigration, the industrial revolution, the introduction of contra-
ceptive devices, improvements in medical knowledge, and introduction of
public health measures.
Man, a highly social being, is an animal as well. In form and function,
development and growth, reproduction, aging, and death, he is a biological
entity who shares the attributes of physical life with the millions of plant
and animal species to which he is related. This relationship, known since
prescientific times, became part of established science long before the
theory of evolution was proposed. It is the reason why studies of fungi
and mice, flies and rabbits, weeds, cats, and many other types of organisms
have contributed to understanding man and to improving his health and
biological well-being, and why future studies with experimental organisms
will bear on man's own future.
Man's mental attributes form a superstructure that does not exist inde-
penderlt of his organismal construction. Human thought is based on the
human brain; the brain-and, hence, the mind, the "self" of each person
is one of the derived, developed expressions of the genes that he inherited
from his parents. Man's capacities are, thus, inextricably linked to his
genes, whose molecular nature is now understood to a very high degree,
but which presently lie outside his control. The social creations of man
language, knowledge, culture, philosophy, society have an existence of
their own and are transmitted by social inheritance from generation to
generation. But they depend for both their persistence and change on the
genetic endowments of the biological human beings who are subjected to
them and, at the same time, make them possible.
In these considerations, "man" should be taken as inclusive of all human
beings on our planet. The brotherhood of all men is not only an ethical
imperative; it is based on our common descent and on the magnitude of
the shared genetic heritage. Man has organized "nations" geographic,
political, economic, military, and cultural units that insist on their
sovereign status. The short-range future of man will differ among these
sovereign groups, particularly between the "developed" and the "under-
developed" nations. This discussion is particularly concerned with prospects
in the developed countries.
THE GREAT HAZARDS
War
The considerations of the future of man that follow presuppose that man-
kind will not be subjected to a nuclear holocaust. If such an event were to
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BIOLOGY AND THE FUTURE OF MAN
occur, the problems of retaining or re-establishing social organization, the
breakdown of health services, including the production and distribution of
life-saving drugs, and the ensuing threat of worldwide epidemics would take
precedence over all other aspects of human affairs. Modern technology is
sufficiently powerful to make complete extermination of man a possibility.
To accomplish such a deed would require overwhelming use of nuclear
weapons over large areas of the globe and a deliberate effort to distribute
lethal levels of fallout over all inhabited regions. Barring such extreme
measures, some of mankind would probably survive a nuclear war. The
acute dose of irradiation required to kill human beings in a single, brief
exposure is relatively small. Accordingly, direct radiation from nuclear
explosives would take an immense toll, but the survivors would probably
be able to repopulate the earth.
Those who survived the immediate impact of nuclear explosions would
be subjected to chronic irradiation from fallout, which would lead to a
variety of deleterious effects. In addition to the damage to their own bodies,
the survivors would produce egg or sperm cells that would contain many
new mutations leading to abnormal offspring. Nevertheless, the radiation
dose that the survivors would have received from the initial exposure and
subsequent fallout might often be low enough to permit them also to produce
normal-appearing and normal-functioning children, provided the survivors
would still want to create a new generation. Ironically, it is precisely under
these circumstances that social inhibitions against control of human genetics
would dissolve most rapidly; post-nuclear-war man would almost certainly
utilize available genetic understanding and biological technology to guide
the evolution of his species.
Should Homo sapiens, as such, survive nuclear war, there can be no
guarantee that he could reconstruct his civilization. Our technologically
developed society rests on a complex web of production that could be rebuilt
only with extraordinary difficulty. Meanwhile, this would probably occur
in a world significantly altered. The ecological consequences of worldwide
fallout and long-term rise in radioactivity are virtually impossible to predict.
But plant and animal species vary remarkably in their radiosensitivity, and
surely current food chains would be disrupted with such profound ecological
consequences that it is not clear that man could continue to find sustenance,
warmth, and shelter.
Similar considerations may well apply to the possibility of widespread
use of biological warfare. The constructive understanding of life that
biology provides can also be used for wholesale destruction of life. Once
undertaken, war, in the future as in the past, is liable to grow beyond
control, whether it be conducted with physical, chemical, or biological
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430 THE LIFE SCIENCES
means. A future for man can be assured only when the ultimate danger of
modern war is fully recognized and mankind abandons warfare.
Man and His Environment
For thousands of years, since first he became a farmer, man has changed
his general environment. Some such actions were favorable; for example,
during a previous era the rainfall in the American plains was limited,
enabling the Indians annually to burn the prairies to drive the buffalo. The
resulting debris created our great grasslands and helped generate the deepest,
grandest soils on this continent. But, deforestation and primitive methods
of agriculture have denuded vast areas and exposed their soil to erosion.
It was just such practice that silted the Tigris and Euphrates rivers, thus
contributing to the demise of the great Sumerian civilization. With con-
tinuing loss, precious soil is essentially irretrievable. Return of the dust
bowl of the south central United States to productive agriculture will require
years of expensive and intensive effort, which will be economically rational
only when national requirements are desperate. Hundreds of thousands of
acres of forest were despoiled without provision for reforestation. Large
areas of South American forest have been cleared for agriculture, despite
the fact that, within a year or two, the rich forest is replaced by a concrete-
like laterite soil; until research provides the technology to prevent this,
such forest should remain in the native state. But when such knowledge is
in hand, vast areas could be opened for productive agriculture. Excessive
hunting of some animals for food, and of the large predatory animals either
for sport or in self-defense, has wiped out many species either wholly or
in many regions. Witness the slaughter of the giant, Hightless Moa by the
Maori after they found New Zealand (about A.D. 1200) and the decreasing
numbers of virtually all the great birds of our own country. When Euro-
peans first came to this country, it harbored 5 billion passenger pigeons and
50 million bison. The former are gone and only 6,000 of the latter remain.
Less than 3 percent of the original acreage of redwoods now stands, and
there is no record of the disappearance of great numbers of species from
our prairies, lakes, and forests. And mankind is the poorer. The prospect
of a planet populated exclusively by man and the few animal species he
has domesticated is bleak indeed. How grim to think of a world without
tigers, whales, condors, or redwoods!
The rise in population density, the operations of modern industry, and
the diverse products of modern technology have led to pollution of air,
water, and soil by a wide variety of chemical compounds and even unde-
sirable proliferation of certain living forms, notably algae, while defiling the
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BIOLOGY AND THE FUTURE OF MAN
landscape and minimizing the exposure of urbanites and suburbanites to
natural surroundings. Large-scale use of pesticides can start a chain in
which these substances concentrate in plant and animal tissues and, when
ingested, accumulate in the adipose tissue of the human body. As an
illustration of this process, consider the record of Clear Lake, California,
where DDD (a breakdown product of DDI) entered the lake at 0.02 part
per million (ppm). A year later, its concentration was 10 ppm in the
plankton, 900 ppm in fish that eat the plankton, and 2,700 ppm in fish
that eat fish that eat plankton. No data are available concerning people who
ate such fish. Similarly, the routine addition of antibiotics to feed of
domestic animals leads to their ingestion by man. Exposure to repeated low
levels of these drugs may inhibit growth of sensitive organisms and may
thereby foster growth of resistant strains and so may decrease the effective-
ness of these drugs to fight infection.
The effects of these changes in the environment on man himself are not
known. Although it is possible that some of the agents to which man is
now inadvertently exposed will cause serious disease, shortening of the
life-span, decreased fertility, or deleterious mutational changes in genes,
none of these has as yet actually been demonstrated to have occurred. This,
however, does not imply that dangers do not exist. Such possible effects
may be numerous, yet difficult to discover. It has taken decades to establish
the statistical relation between cigarette smoking and lung cancer; the same
may also hold true for the relation between new factors in our environment
and other diseases.
Unlike the effects of acute, heavy doses of deleterious substances that
rapidly lead to severe illness, pollutants are taken up in small amounts
over long periods. Their effects, therefore, may be delayed for years or
decades. Moreover, different individuals probably react differently to the
same low level of exposure to a foreign substance. Some may excrete more
of a given compound than others, thereby avoiding accumulation. Some
may decompose the agent in their tissues, while others leave it unchanged.
Some may be more resistant to its effects. If, as an arbitrary figure, one
in 1,000 individuals will suffer ill effects from a specific agent, causal
relationships can be revealed only by very large-scale studies of whole popu-
lation groups. Yet if one incident in 1,000 seems a small effect, consider
that, in a population of 200 million, as many as 200 thousand individuals
would experience damage. Conceivably, the incidence of heart attacks
may have been increased to this extent by the carbon monoxide of auto-
mobile exhausts in regions where smog formation is heavy, but this has
yet to be demonstrated. Appropriate studies would have to make use of
large cohorts of people followed in their pattern of diseases, fertility, and
life-span over very long periods perhaps longer than the professional
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THE LIFE SCIENCES
life-span of a single generation of investigators. There is precedent for
such studies in the research on the relation of smoking to lung cancer, but
the scale of such studies must be greatly expanded.
Until reliable evidence thus obtained becomes available, public health
measures designed to minimize exposure to such pollutants are patently
advisable. But surely a rule of reason should prevail. To only a few
chemicals does man owe as great a debt as to DDT. It has contributed to
the great increase in agricultural productivity, while sparing countless
humanity from a host of diseases, most notably, perhaps, scrub typhus and
malaria. Indeed, it is estimated that, in little more than two decades, DDT
has prevented 500 million deaths due to malaria that would otherwise have
been inevitable. Abandonment of this valuable insecticide should be under-
taken only at such time and in such places as it is evident that the prospective
gain to humanity exceeds the consequent losses. At this writing, all avail-
able substitutes for DDT are both more expensive per crop-year and de-
cidedly more hazardous to those who manufacture and utilize them in crop
treatment or for other, more general purposes.
The health problems engendered by undesirable contaminants of the
environment may also be raised by substances that are intentionally in-
gested. Only large-scale, long-term epidemiological research will reveal
whether the contraceptive pills, pain killers, sleeping pills, sweeteners, and
tranquilizers, now consumed on so great a scale, have any untoward long-
range effects on their consumers.* Man has always been exposed to the
hazards of his environment and it may well be that he has never been more
safe than he is today in the developed nations. Food contamination is
probably minimal as compared with that in any previous era, communal
water supplies are cleaner, and, despite the smog problem, air is probably
less polluted than in the era of soft coal or before central heating systems
were the norm. Witness the fact that jungle-dwelling natives of South
America exhibit a considerably greater incidence of chromosomal aberra-
tions in their somatic cells than does the American population. But modern
man also increasingly exposes himself to the chemical products of his own
technologies and has both the biological understanding to ascertain the
extent of such hazards and the prospect of technological innovation to
minimize them where they are demonstrated. To do less would be im-
provident and derelict.
The federal record systems, particularly those of the Veterans Adminis-
tration and the Department of Defense, are already available for epidemi-
ological follow-up studies among veterans. They could be made still more
useful by utilizing record linkages, i.e., linking together the many inde
~ This sentence was written in June 1969. Revelations of the untoward effects of
both steroid contraceptives and cyclamates were made public months later.
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BIOLOGY AND THE FUTURE OF MAN
pendent records of births, illnesses, deaths, and other vital statistics in the
defense and social security agencies and many others. While this entails
the possibility of intrusion into the privacy of individuals, it should be
possible to erect safeguards against misuse. Such safeguards will be effec-
tive if the prevailing climate of opinion welcomes the attainment of useful
information and forbids authoritarian attempts at improper exploitation of
linked data. Man's biological future depends on knowledge of his experi-
ences, good and bad, and record linkage is an important means of acquir-
ing such knowledge.
Even more subtle than the effects on man of pollutants and of specific
agents may be the effects of changes in his general pattern of living. Urban
aggregation has removed many men from natural surroundings. The in-
creased level of environmental noise, caused by industrial procedures and
automobile and airplane engines, has added a new dimension to sensory
exposure. Crowding together in overpopulated regions has greatly changed
the interrelations among people who, only a few thousand years ago, lived
in small bands with minor contact with one another.
Development of the science of animal behavior is beginning to give some
insight into the interrelations between genetically founded behavioral attri-
butes, the effects of early training, and the effects of the immediate environ-
ment on overt behavior. We are prone to think of hostility, crime, and
other antisocial behavior as conditioned by social circumstances. And there
is, indeed, ample evidence to support this belief. We do not know, however,
how much personal unhappiness and social distress is a consequence of
man's basic biological nature in conflict with an unnatural, essentially non-
human environment. The stereotyped movements of caged polar bears,
viz., the reaction of bears to a non-bearlike environment, may well have
analogies in mentally ill patients. Undesirable modes of behavior as well
as various psychosomatic illnesses may frequently be extreme expressions
of maladjustments of the human animal. Hopefully, research in behavioral
biology will furnish deeper insights into man's nature, and application of
these insights may lead in the not-too-distant future to fundamentally new
parameters for environmental engineering. These will endeavor to fit the
environment to man instead of leaving man unfit for the environments he
created. Important to such studies are the nonhuman primates apes and
monkeys; every effort should be made to assure the survival of as many
such species as possible.
Scientific advancement has enabled man to triumph over his environ-
ment. With technological skills and machinery he is able to move, change,
and control natural resources for his agriculture, forestry, fisheries, recrea-
tion, and urban and industrial development. The wasteful, injurious prac-
tices of yesterday have largely been abandoned. Forests are replanted as
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THE LIFE SCIENCES
they are timbered; soils are fertilized so as to compensate for the minerals
removed by the plant harvest; saline soils are restored to useful tillage by
large-scale leaching; a beginning has been made at reversal of thoughtless
practices that could result in the almost irreversible death of large lakes.
Although Lake Erie is in serious trouble, Lake Washington is being recov-
ered, and Lake Tahoe may yet be saved. Civilization depends and will
continue to depend upon the renewable resources of the environment-
land, water, air, and populations of plants and animals, both wild and
cultivated. Fortunately, the public and its representatives are increasingly
anxious about the status of these resources and the vital role they play in
our survival and general well-being.
Environmental pollution becomes of increasing concern as the human
population congregates in cities and occupies more of the landscape. The
public is pressing for greater understanding of the function and interaction
of the biological and physical elements of the environment and for appli
cation of this understanding to the management of the renewable resources
that supply man's food, clothing, recreation, and shelter. This sense of
urgency, arising originally from the desire simply to assure the viability
of life an char Planet is heightened by growing public appreciation of the
^~ ^~ i- 7 ~ I-
1
importance of beauty, natural and manmade, ~n our surroundings for the
improvement of the quality of life.
Many reports have directed attention to the more obvious gross problems
of managing the environment, problems that derive from a combination of
population growth, advancing technology, and increased technological pro-
ductivity. Concern has been expressed with respect to rising atmospheric
CO,; increasing particulate content of the atmosphere; buildup of radio-
activity; accumulation of diverse chemicals in lakes, streams, rivers, coastal
waters, and the ocean itself; soil erosion and destruction; replacement of
fertile, green farm and woodland by highways and towns; rising noise
levels; and "thermal pollution." Figure 49 displays the record and projec-
tion of various endeavors of our society, each of which must necessarily
adversely affect the environment. If these projections are even approxi-
mately correct, and if each of these enterprises grows without appropriate
monitoring for its ecological consequences' the totality could constitute
the saddest, most brutal, and most disastrous act of vandalism in historic.
Economic growth, insofar as it leads to higher standards of living, better
health, and national security, is clearly to be desired and fostered. But life
should be worth living, and this generation should assure that it can transmit
to posterity a land whose beauty and resources have been safeguarded,
embellished, and protected. To do so demands a level of regional and
national planning, with due regard for ecological understanding, without
historic parallel. Moreover, we must assume the burden of transmitting
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BIOLOGY AND THE FUTURE OF MAN 435
Air
Freight Air
Transportation (Revenue Passenger
3150% \ Miles) 2615%
A_
8
1l 1250
,
a)
Q
° 1000
>
a)
C:
._
o
~ 750
~5
0
CO
Cal
._
-
o
c 500
o
._
x
LL
~ 250
a)
CL
Public Construction
/ of Highways 2020%
~v I .............. . ~.. ..
1947 '50 '60 '70 '80 '90 2000
................... Utility Sales of Electricity
1 3 50 %
'~4 Chemicals and Products
go Residential Construction
.. Public Construction of
<~4 Water and Sewerage
.~ Automobiles
~4 (Annual Production)
'~4 Nonferrous Metals and
. ~ Products
,.1 Paper and Paper Board
., Production
..~4 Gross National Products
.~4 Petroleum Consumption
·...
.......
.......
.....
......
d Steer Ingot Production
and Detergents
FIGURE 49 Projections of expansion of certain industries that have an influence on
pollution. Medium-level projections, 1970-2000. (Data from H. H. Landsberg, L. L.
Fischman, and J. L. Fisher, Resources in America's Future, published by The Johns
Hopkins University Press for Resources for the Future, Inc., Washington, D.C., 1963.)
such understanding and planning capability to the developing nations,
most of which still retain the native qualities of their environments and are
in danger of galloping destruction of their resources as they race to develop
their technological capabilities and to achieve economic independence
and a reasonable standard of living.
Biologists and engineers should work jointly to design cities of quality
and beauty. Dwellings and industrial structures should be surrounded by
at least minimal lawns and plantings of ornamental trees, shrubs, and
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436
THE LIFE SCIENCES
flowers. There can be no relaxation of efforts to assure "clean" air and
water, although useful operational criteria for these remain to be established.
The burden of responsibility must be made to lie with those whose activities
introduce contaminants into the environment. Even now, there are tech-
nological means for dealing with most pollutants at the source. A rational
society will insist that these means be utilized and that new, cheap, and
efficient means be continually sought. Where none exist, it becomes
essential that the advantages afforded by polluting activities nondegradable
detergents and pesticides, heavy use of fertilizer, the exhaust of internal-
combustion engines, the sonic boom, and the contrails of a supersonic
transport be weighed against their cumulative effects on mankind. It is
doubtful that, at this writing, the evidence on which to rest such judgments
exists. Patently, this evidence must be sought.
Through care, planning, and utilization of the sciences of agriculture
and forestry, the landscape of the country can be conserved, returning it to
its simple charm, with neither billboards nor automobile graveyards. More-
over, a great and complex effort based on ecological understanding will be
required to cope with the pressures that annually result in conversion of
one million acres of farm and wildland to highways and building sites.
Certain areas representative of nature seashore, mountains, desert,
forest should be preserved forever wild for recreation and on a scale
adequate to preserve the natural biota. Ecologists and environmental
biologists, together with other scientists, should combine to develop a
strategy for the wise use of our renewable resources and the preservation
of an attractive environment. The attainment of these goals does not
depend alone on the technical skills of biologists and other scientists and
engineers; people generally must desire to live in harmonious, healthful
environments. Without broad social motivation supporting their use, the
knowledge and the skills of the specialists will lie fallow.
The Size of Human Populations
In the seventh century, according to the records of the Church of Mayo, two kings
of Erin summoned the principal clergy and laity to a council at Temora, in conse-
quence of a general dearth, the land not being sufficient to support the increasing
population. The chiefs . . . decreed that a fast should be observed both by clergy
and laity so that they might with one accord solicit God to prayer to remote by some
species of pestilence the burthensome multitudes of tile inferior people.... St. Gerald
and his associates suggested that it would be more conformable to the Divine Nature
and not more difficult to multiply the fruits of the earth than to destroy its inhabitants.
An amendment was accordingly moved "to supplicate the Almighty not to reduce
the number of men till it answered the quantity of corn usually produced, but to
increase the produce of the land so that it might satisfy the wants of the people."
However, the nobles and clergy, headed by St. Fechin, bore down the opposition and
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BIOLOGY AND THE FUTURE OF MAN
called for a pestilence on the lower orders of the people. According to the records
a pestilence was given, which included in its ravages the authors of the petition, the
two kings who had summoned the convention, with St. Fechin, the King of Ulster
and Munster and a third of the nobles concerned....
W. J. Simpson,
A Treatise on Plague
The upsurge in the growth of human populations constitutes the major
problem for the immediate future of man. Accordingly, it is difficult to
exaggerate the urgency of deepening our biological knowledge of man and
his environment. There is every reason to expect that, by the end of the
century, a brief 30 years from now, the world will have twice its present
population. Unless forestalled by a worldwide holocaust, in the year 2000
the world population will surely be not fewer than 6 billion people, and
may well exceed 7 billion. (See Figure 50.) Since the means for improved
control of disease are already at hand, if the food supply keeps pace, a
World Population
(billions)
-~7.5
. ........................ . -
0 200 400 600 800
~1144 ~8~
1000 12001400 1600 1800 2000
1900
Date
-. ~
I.............
I............
.........
I.............
~ ~
l
l
4
15
30
2
\
100
)8
)
from the
beginning
FIGURE 50 World population growth (projected with assumption of constant
fertility levels and declining mortality). (Small numbers outside parentheses indicate
the rapidly decreasing number of years required to increase world population by a
billion people.) (From World Population: A Challenge to the United Nations and
Its System of Agencies, UNA-USA National Policy Panel on World Population,
May 1969.)
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United States
. _ -Canada, Australia
- Latin America
rEurope
anon | Africa USSR
1968
1930
THE LIFE SCIENCES
world population of 7 billion will be reached even if present birth rates
are considerably reduced. Population growth is occurring most rapidly in
the newly developing nations, where abject poverty is widespread, the mass
of the population is uneducated, and the industrial sectors of their econ-
omies are poorly developed. (See Figure 51.)
Moreover, future demands on the biosphere are not to be measured by
simple extrapolation from the present. Much of the present population is
badly nourished, while, because of improved communications and appre-
ciation of the living standards of developed nations, popular aspirations
for improved living conditions are high in almost all nations. Even a
doubling of per capita consumption of protein, clothing, and shelter would
leave present aspirations unfulfilled. If the projected doubling of the
world's population is realized, and if political order is to be maintained,
it is not unreasonable to expect that the demands on the biosphere by the
end of the century will be three or four times those-of the present! The
problem of achieving such increases becomes staggering when we realize
that the end of the century is so close that this year's infants will then be in
the middle of their childbearing period. Moreover, regard for the human
heritage requires that these needs be met without despoiling either the
quality of man or the material base from which he draws life.
Distribution of Population
India China
Japan Rest of Asia 7.5 billion
1830
/
-3.4 billion
[I...'
,... ~
~ :#
~ ::::::::O
|-.' '! ~
.'
~ .. ,.
#,
. .
// / 2.0 billion
' ~ / 1968 2000
/U.S. 200 350
/ Canada, Australasia 40 70
/ Latin America 270 760
a.,_ A=^ 57Q
860
U.S.S.R. 240 400
India 520 1330
China 730 1480
Japan 100 140
Rest of Asia 590 1550
Europe 460
Africa 330
1.0 billion
FIGURE 51 Projected population of developed and underdeveloped nations in the
year 2000. (From World Population: A Challenge to the United Nations and Its
System of A agencies, UNA-USA National Policy Panel on World Population, May
1969.)
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BIOLOGY AND THE FUTURE OF MAN
be applied to the immediate problems of agricultural production is not
due to biological limitations of genetic endowments in different human
Livery region Is poten-
tially able to produce the numerous trained persons needed to explore and
solve the specific problems of the region. Obviously, these problems are
not restricted to agriculture. Each region requires a corps of local scientific
and engineering specialists to make available to its population the bene-
ficial results of industrial and scientific technology, and American technical
assistance should give high priority to assisting in the endeavor to train
such specialists.
The immediate demands on the biosphere have been generated and
exacerbated by rapid population growth, which, particularly in the devel-
oping nations, is the consequence of the almost abrupt inauguration of
public health and sanitation measures, producing drastic reduction of the
death rate while the birth rate remained unchecked. Because no imaginable
program of population control could restrain population growth signifi-
cantly in the next decade, the emergency problem is to attain, as rapidly
as possible, adequate levels of education and significant local programs in
agriculture and related science and technology for the vast numbers of the
human race. We are not optimistic that this can be achieved in time to
avert disaster in the 1970's, but the attempt must be made. It is all too
evident that the surplus agricultural productivity of a few developed nations
Canada, Australia, the United States" even if used to the full, can have
little impact in this worsening situation. Moreover, population growth in
these nations will, in time, require domestic utilization of their own pro-
duction.
If this estimate of the situation is correct, the acute problem is not that
of population size itself but of the speed of modernization and the extent
to which the gains so realized are offset by the speed of population growth.
The speed of modernization turns on many factors, on national and inter-
national allocation of resources for space' war, schools, and factories,
inter alla. But basically it also depends, even at quite local levels, on the
extent to which the growth of agricultural production can be made to
exceed that of population. Investment in development can be made only
after the current costs of growth have been met.
-
groups, but to the limitations of their education. ~
POPULATION CONTROL: THE LONG-TERM PROBLEM
The long-term prospects for a truly human civilization depend in very
large measure on whether humanity can, in time, succeed in moderating its
fecundity. Only if this effort is successful, and early, can our progeny be
offered the opportunity to relish the gift of life and to maximize their own
441
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442
THE LIFE SCIENCES
human potential. The dimensions of the problem are dramatically evident
in the remarkable diminution in the time required for doubling of the
world population, as seen in Table 69.
This remarkably accelerated growth, largely the result of decreasing
death rates due to simple public health and hygienic measures accompanied
by commensurate increases in agricultural productivity, occurred first in
Europe and the United States and is now operative also in many of the
developing nations, with startling consequences. Witness Brazil with a
population of 17.5 million in 1900, 52 million in l9SO, 71 million in 1960,
83 million in 1966, and an estimated 240 million by 2000, or a 14-fold
increase within We twentieth century!
Yet concern for population growth is not new. In Politics, Aristotle
warned that ". . . neglect of an effective birth control policy is a never-
failing source of poverty which, in turn, is the parent of revolution and
crime," and he advocated that parents with too many children practice
abortion. He went unheeded through the following centuries as the Romans
encouraged large families to man their wide-flung armies, the Judaeo-
Christian ethic considered children as gifts of God, and St. Augustine stated
the purpose of Christian marriage to be procreation, a view unmodified by
the Reformation. Much earlier, Tertullian noted that "the scourges of
pestilence, famine, wars and earthquake have come to be regarded as a
blessing to crowded nations since they served to prune away the luxuriant
growth of the human race." From time to time, advocates of population
control appeared, most particularly Malthus, who stated that, otherwise,
TABLE 69 Time Required to Double World Population
TIME
WORLD POPULATION YEAR REQUIRED
(YEARS)
250~000~000
500,000,000
1,000,000,000
2,000,000~000
4,000,000,000
8,000,000,000
1650
1 850
1930
1 97Sa
2005 a
1,649
200
80
4Sa
30a
0 Estimate.
OCR for page 443
BIOLOGY AND THE FUTURE OF MAN
population would always rise to the limits of food-production capacity, so
that necessarily there would always be hunger and poverty. (Ironically,
Malthus rested his case on the history of eighteenth-century United States.)
Unfortunately, his teaching was rejected both by the Christian ethic and
by Marxism, which taught that overpopulation is merely a capitalist notion
invented to justify the poverty of working-class peoples and is rectifiable
by enhanced production and improved distribution rather than by birth
control.
Malthusian predictions have largely been justified, although he foresaw
neither the consequences of the introduction of agricultural technology nor
the demographic consequences of simple hygienic measures. Today, these
problems must be considered separately in global and local contexts. The
food crisis of some developing nations, considered earlier, is patently urgent.
Yet, worldwide, since about 1950 agricultural productivity has grown by
about 3 percent annually, while population increase has averaged less than
2 percent. Indeed, it is estimated that if worldwide per capita food con-
sumption had held constant at 1955 levels, despite the population increase
by 1975 there would have been a world surplus of 40 million tons of wheat
and 75 million tons of rice. This will not occur because of both rising per
capita food consumption and the controlled productivity practiced, in vary-
ing degree and kind, in the United States, Australia, New Zealand, Canada,
France, and the Argentine. Meanwhile, the developing nations, caught up
in the worldwide revolution of rising expectations, find themselves short
of food and of capital for development.
Income for development can be generated by increased production and
by decreased reproduction. Clearly, both are needed. Some inherently
undesirable means to decrease the rate of population growth, e.g., war,
famine, pestilence, are all too evident. On the other hand, populations
that have learned to reduce their fertility to the point where they enjoy
good health and the longevity characteristic of the more developed nations,
and whose growth amounts to only 1 percent per year should encounter
no substantial difficulty in reaching a stationary position if that is clearly
desirable. Only as that occurs can increased production of agriculture and
the extractive and manufacturing industries be utilized for development
and increase in the general standard of living. It may well be asked how
many countries can be expected to do this soon enough. Markedly in-
creased agricultural productivity accompanied by population growth
inevitably leads to rapid urbanization, frequently at a rate in excess of any
prospect of gainful employment of the translocated individuals. Yet this
process, at a moderate rate, is imperative if a developing agrarian society
is to acquire a sufficient urban population to sustain its growing industry,
educational system, etc.
443
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THE LIFE SCIENCES
As we have indicated, if the oncoming food-shortage crisis can be averted,
known technology, if put into practice, can readily so enhance food produc-
tion as to defer the world food problem almost indefinitely. It is the combi-
nation of new strains and application of fertilizer that has so remarkably
increased agricultural yields in Europe, Japan, and the United States. In
a general way, application of a ton of fertilizer nitrogen yields an increment
in crop production equal to the basic yield of a 14-acre plot. Stated
differently, there are about 3.5 billion acres of land presently under culti-
vation; application of $10 worth of fertilizer per acre would increase pro-
duction by about 50 percent, i.e., for $35 billion per year or $10 per capita,
worldwide, world food production would rise by the equivalent of 1.7
billion acres of average land and a 50 percent increase in available food,
per capita. Moreover, it has been calculated that if all land now in tillage
were cultivated as in Holland the world could support 60 billion people
on a typical Dutch diet; if it were managed as in Japan, it could support
about 90 billion people on a typical Japanese diet. And all this is possible
apart from the realizable expectation of yet another agricultural revolution
based on improved control of agriculture, growth of food yeast, bacteria
and algae, or synthetic foodstuffs based on petrochemicals. Approximately
one acre is required to feed one man by efficient current agriculture, yet
a one-square-yard tank growing algae can produce all his caloric, protein,
and vitamin needs! All of which is to say that measures to upgrade agri-
cultural practice in the developing nations could forestall a Malthusian
crisis for more than a half century, even at current rates of population
growth. But with what consequences?
The problem of population growth involves much more than merely
increasing agricultural production. The constraints to population size are
all too visible even in the traditional self-sufficient agrarian society. Such
societies have rarely been able to combine high population density with
good health and relative freedom from poverty. But it is hard to specify
the limits to the density of population that can be supported in health and
prosperity by a highly educated population making sophisticated use of
energy and raw materials and continuing to develop both its basic science
and technology.
There is reason to believe that, given the time and effort required to
increase all forms of production sufficiently, this planet can sustain in
relative abundance a total population considerably larger than the present
one. Although no data are available to establish what the maximum might
be, it is patently very much larger than at present. One can argue, however,
that the maximum possible is decidedly greater than the optimum. Even
the present population suffices to populate the planet, at all times, with the
diversified human talent required to contribute to progress on all human
OCR for page 445
BIOLOGY AND THE FUTURE OF MAN
fronts- science, the arts, industry, government, eta. At some point, industry
must forego population growth as the underlying basis for economic ex-
pansion. Meanwhile, many of the most tragic ills of human existence find
their origin in population growth. Hunger, pollution, crime, despoliation
of the natural beauty of the planet, irreversible extermination of countless
species of plants and animals, overlarge, dirty, overcrowded cities with
their paradoxical loneliness, continual erosion of limited natural resources,
and the seething unrest that creates the political instability that leads to
international conflict and war, all derive from the unbridled growth of
human populations. The fortunate nations are those that have, spontane-
ously rather than as a matter of national policy, achieved a low rate of
population growth or an exact equilibrium of the birth and death rates.
Accordingly, another set of important emergency problems of a biological
nature are those relevant to a reduction of human fertility. In the long
run, birth rates must come down if death rates are to stay low, and in the
short run, lower fertility would speed the process of modernization by
widening the difference between the growth rates of population and pro-
duction. Reductions of the birth rate in the underdeveloped countries have
an additional advantage. High birth rates produce high proportions of
young people. In virtually every country with a birth rate of 40 or more per
1,000 population, more than 40 percent of the total population is under
age 15. Under these circumstances it becomes almost impossible for such
a society to increase its working capital- to generate enough wealth for
school construction, higher education, improved housing, or industrial
plants. In consequence, for example, the illiteracy rate must surely rise,
despite national determination to lower it.
In advanced countries with low birth rates, between 25 and 30 percent
of the total population is under age 15. A reduction in birth rates brings
down rates of growth and reduces the proportion in the ages of childhood
dependence. Correspondingly, it increases the proportion of the popula
tion in the productive years of life.
Indeed, very high birth rates speed population growth in two ways:
( 1 ) they swell the entering stream of life; and (2) by creating young popu-
lations they cut the rate of depletion through death. Today, the lowest
crude death rates (i.e., annual deaths per 1,000 population uncorrected
for age) are not found in the most highly developed countries. The world's
lowest crude death rates are found in such places as Taiwan, Singapore,
Puerto Rico, and Chile, where health protection has become relatively
good and a history of high birth rates has left a young population. In the
long run, reductions in birth rates reduce growth both directly and indi-
rectly by increasing the average age and, other things being equal, the
crude death rate. Clearly, the possibilities of modernization would be
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THE LIFE SCIENCES
greatly enhanced, globally, if rates of growth could be cut in 15 years from
3 percent to, say, 1 percent by reductions in birth rates. This would mean
that populations now growing at rates that double in 23 years would come
to a rate that would give them 69 years in which to absorb the increase,
viz., the burden of natural increase in the newly developing countries would
then be about that experienced by the United States in recent years.
Most societies and individuals desire to limit. the size of families, but
they are usually not content with a family size corresponding to zero growth
of the population. Although, at the present stage of population growth,
any reduction in family size is important, ultimately the mean family size
will have to be limited to a replacement number. Family planning is not
equivalent to population control. Family planning is the rational and
deliberate spacing of children in the number desired by the parents. But
that number is determined by cultural considerations, family income, and
ego satisfaction in the developed nations and by the economic utility of
children in the underdeveloped nations. Accordingly, large families are the
norm among the affluent and among the ignorant poor. Population control
demands that families be limited to the replacement rate.
Nothing can do more to help obtain reductions of fertility than the
development of more efficient, cheap, safe, reversible, and acceptable
methods of contraception. People will use even the best of methods only
when they want to have fewer children. Historically, whereas strongly
motivated couples have even utilized inadequate methods of contraception
and resorted to abortion, weakly motivated populations must be enticed to
use even the best possible methods. Today, readiness to accept contracep-
tion is widespread. More than half the population of the developing nations
live under governments that have decided, as a matter of national policy,
to foster the spread of family planning and limitation. The list includes
most of the countries of Asia and a goodly number in Africa and Latin
America. Most of these countries are developing educational programs to
interest and inform their people and service programs to give them supplies.
Careful surveys of attitudes toward reproduction have been made in more
than 20 countries. Virtually everywhere, the majority of women desire
to limit their childbearing. This does not mean that they want only two
or three children, but that they want to stop before their families get truly
large. Moreover, where services and supplies are made available, women
are beginning to seek them in large numbers. Taiwan, South Korea, Hong
Kong, and Singapore have clearly reduced their birth rates through their
family planning programs.
Today, in the developed nations, contraception has changed rapidly from
use of the older conventional methods to the combination steroid pill. In
underdeveloped countries, new contraceptors are mainly using the plastic
OCR for page 447
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BIOLOGY AND THE FUTURE OF MAN
intrauterine device. Neither method is perfect, but both are spectacularly
effective and successful compared with the conventional contraceptives,
"rhythm" methods, Eric. The availability of the cheap intrauterine device
has encouraged governments of underdeveloped nations to build the organi-
zations they require to spread family planning practices. With such
organizations in being and operative, the next technological innovation can
be introduced much more rapidly. It is because they have effective methods,
hope for better ones, and the organizations to make use of them, that such
countries as South Korea, Taiwan, India, and Pakistan now hope to halve
their birth rates in 15 years. If they could do so, their long-run problems
of modernization and economic development would be greatly simplified.
The world needs better methods than are now available. The pill and
the intrauterine device represent major innovations because, temporally,
they separate contraception from coitus. The intrauterine device is prob-
ably at a very early stage of development. An unacceptable proportion of
all users spontaneously eject it, bleed, or suffer discomfort. On the other
hand, apparently the majority of those who accept it wear it without aware-
ness and with very high effectiveness. Two to three years after acceptance,
50 percent or more of women continue to wear their devices. It is likely
that better procedures, better materials, and better shapes will lead to a
greatly improved experience. Clearly, it is imperative that appropriate,
vigorous investigation be undertaken to solve the riddle of the mode of
action of these devices and to ameliorate their occasional side effects.
Similarly, work is needed to reduce the side effects of steroid pills, to
minimize their effects on lactation and on thromboembolic phenomena, to
reduce their costs, and to establish systematically and in sustained fashion
the actual experience of those who take them, to reduce the frequency of
subsequent multiple births and, most importantly, to establish the biological
consequences of long-term use with complete certainty. Similarly, an effort
to find means of replacing the oral route of administration with a depot
injection, vie., an injection allowing a steadier rate of absorption and, hence,
smaller and longer-lasting doses, would be well repaid.
Meanwhile, as this research proceeds, we deplore statements decrying
use of steroid pills on the ground of their manifest occasional untoward
side effects. Since the death rate from such usage is well below the death
rate from pregnancy itself, these pills not only afford millions of families
the opportunity for a richer, fuller life while checking the demographic
explosion; on balance they also spare the lives of a significant number of
women who would otherwise die of the complications of pregnancy.
It would be highly desirable, of course, to have a method that is, in
effect, permanent until positive measures are taken to counteract the con-
traceptive. Children are often conceived as a consequence of careless con
447
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THE LIFE SCIENCES
traceptive practice. Doubtless, birth rates would drop faster if there were
a method in which carelessness meant failure to counteract a contraceptive.
Clearly, however, such a development could pose serious problems of
personal freedom unless the counteracting agent were freely available.
Only a beginning has been made in relevant basic research. Among
other things, we need to know a great deal more about tubal events, includ-
ing gamete transport, fertilization, and zygote physiology. The fields of
neuroendocrinology, immunological suppression of reproduction, blastocyst
nidation, gonadotrophin chemistry, and the mechanisms of sex hormone
action urgently need development. An intensive program of basic research
might produce important results that could facilitate population control.
The fundamental knowledge, the techniques, and the requisite base of pro-
fessional skill for such an effort are now beginning to appear.
In the long run, all practical results depend on basic research. But in
the long run, unless birth rates are lowered rapidly, populations will become
multiples of what they are today unless death rates rise. In the past decade,
applied research based on many preceding years of basic research has
made possible the contraceptive pills, the intrauterine devices and, conse-
quently, the beginnings of a birth rate decline in some developing areas as
well as in developed nations. Further basic research is greatly needed to
prepare for yet further advances, and it is the only pathway to completely
new approaches in population control. Meanwhile, intensification and
enlargement of applied research is an urgent necessity.
The United States and other developed nations find themselves in the
embarrassing position of advocating that other nations increase their efforts
at population control. Granted the validity of this position, viz., that it
really does address itself to the self-interest of the affected nations, such
a posture is not readily acceptable when the advice comes from a nation
that has not itself adopted comparable internal policies. Since this country
is in the fortunate position of enjoying a high economic level and a rela-
tively low population growth rate, and while our total population is not yet
excessive for our natural resources but is on the way to becoming so, the
moment is opportune to examine our internal policies and alter these as
seems appropriate.
Clearly, our relatively low rate of population increase reflects the fact
that American parents have not been behaving in the manner seemingly
encouraged by the national mores and laws. Is it not appropriate to recon-
sider laws that discourage abortion, forbid or make difficult distribution of
birth control information and devices, and encourage large families by
income tax forgiveness and by other social measures? These derive from
an earlier ethos when an expanding population was required to develop
the national frontiers. They seem entirely inappropriate today.
OCR for page 449
BIOLOGY AND THE FUTURE OF MAN 449
Nor is the United States immune from the population explosion. Until
recently our population growth has been dominated by the extremely low
birth experience of the depression years and the subsequent war. But the
children of the "baby boom" are just entering the child-bearing population.
Thus, our female population in the age range 16-44 was 32 million in 1940~
34 million in 1950, and 36 million in 1960, but it will be 43 million in
1970 and 54 million in 1980. The potential for an extraordinary burst in
population is evident in the very fact of the existence of this breeding popu-
lation. The current rate of population growth, i.e., the excess of births over
deaths, is about 2 million per year, yet it is estimated that about 500,000
babies per year are "unwanted." Surely, provision to the mothers of these
unwanted babies of information, contraceptive materials, or legal abortions
would make for a happier society while reducing the societal burdens of
population growth.
Moreover, it should be understood that the penalties for population
expansion are far greater in an affluent society than in a marginal economy.
This is already painfully evident in the United States. Rising per capita
real income places less and less tolerable burdens upon the environment:
vastly increased solid waste, nondegradable detergents, pesticides, con-
tainers and trash, more automobiles, heavier traffic, increased CO and CO'
production, more smog, rapid erosion of fields for airports, highways,
parking spaces and suburbia, rapidly increased water usage for anything
. .... . . · .
but drinking, Liz., a~rcondit~on~ng, swimming pools, metal-fabricat~on and
paper-production plants, etc., while the same processes accelerate the de-
pletion of all our nonrenewable resources-oil, iron, and copper ores, etc.
Indeed, this is the lesson of Figure 49. Further, consider the seemingly
impossible burden of coping with the demand for college education: college
enrollments, which were 6 million in 1965, will be 8 million in 1970,
10 million in 1975, and 12 million in 1980. The effort required to meet
all the expectations of this burgeoning population will be enormous and
... ... .
_,
wall utilize more and more ot our precious land and irreplaceable resources.
This is in clear contrast to the burden upon the environment generated by
adding to the population of a developing nation more individuals whose
mean income is but a few hundred dollars a year. Clearly, the national
interest and our individual interests would be well served by all measures
that would damp the demographic explosion at home as well as abroad.
There is, however, one aspect in which population control and the health
of the population are at odds. Population control would be furthered by
encouraging late marriage, a principal factor in the low birth rate in
Ireland. But the incidence of such congenital defects as Down's syndrome
and cleft palate, as well as of twinning, rises with the age of the parents.
Hence, the optimal situation would be that in which marriage occurs at a
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TEIE LIFE SCIENCES
young age and a family of two or three children follows shortly thereafter.
Success in such a program then requires the full cooperation of society and
20 to 25 years of uninterrupted, successful contraception. Without sterili-
zation, statistically, this seems an unlikely prospect unless research can
provide much simpler and more effective contraceptive methods than those
presently available.
Guarding the Genetic Quality of Man
The human gene pool is the primary resource of mankind, today and to-
morrow. The present gene pool is the culmination of 3 billion years of
evolution and natural selection. The physical vigor, long life, and intel-
lectual capacity of most humans reflect the fact that, historically, natural
selection has minimized the incidence of genes that, when expressed in the
homozygous phenotype (an individual with two identical genes for the trait
in question), would result in serious physical or mental incapacity. How-
ever, advances in medicine in the last few decades have dramatically altered
this situation. The "engineering" of human development so as to permit
survival despite the handicap of such genetic endowment is called
"euphenics" ("eu"- well, "phen" appearance). By ensuring survival
and, thus, permitting the reproduction of such homozygotes, medical prac-
tice has relaxed the selection against such genes.
For example, formerly the intellectual deficit of most phenylketonuric
children was such that they were unable to reproduce; when raised from
birth on a suitable phenylalanine-poor diet they will now, presumably,
marry and have offspring. Instead of "extinction" of the genes responsible
for the disease in the nonreproductive homozygote, this should lead to an
increase in the frequency of these genes in future generations and conse-
quently an increase in phenylketonurics. A similar situation obtains for
all other genetic afflictions that can now be neutralized by various treat-
ments. Consider pyloric stenosis, an abnormal constriction at the junction
of the stomach and intestine; this is a relatively common hereditary disease
of the newborn, occurring in about 5 out of 1,000 live male births and in
1 out of 1,000 live female births. Formerly, most infants so afflicted died
in very early life, but 50 years ago a surgical procedure was instituted that
permits survival and normal health. The survival and later reproduction
of children treated with that procedure has resulted in the perpetuation of
this genotype; among their offspring the frequency of infants with pyloric
stenosis is about 50 times higher than in the general population. And these
children, having been operated upon, will again later produce a surplus of
their own affected kind. Thus, a continuous increase of the disease must
be expected in successive generations. Similar considerations apply to
OCR for page 451
BIOLOGY AND THE FUTURE OF MAN 451
galactosemia and fulminating juvenile diabetes, and the list must grow as
clinical medicine learns to circumvent the consequences of many other
genetic disorders. The extent of this problem is evident from the fact that,
even now, 6 percent of all infants have detectable genetic defects of greater
or lesser seriousness, and all humans must be heterozygous (possessing two
nonidentical genes, one from each parent, for a given trait) for at least a
dozen or more disadvantageous genes.
The speed of accumulation of unfavorable genes in the population de-
pends on many factors. Generally, it is a very slow process, which, for
centuries, will have no easily recognizable effects. Many a "bad" gene
whose effects are overcome euphonically may be said to have lost its
"badness," wholly or to a large degree, so that its accumulation no longer
represents a serious biological load even though it may represent a con-
siderable economic load.
Such accumulation may be contained by genetic counseling, which leads
some carriers of such genes to limit their families or even to refrain from
having children. Genetic counseling can often assure worried persons that
their fears of defective offspring are unjustified or exaggerated, but in some
instances the predicted likelihood of severely abnormal offspring is high.
Knowledge of the inheritance and the variability in expression of the nu-
merous kinds of human defects accumulates steadily, and the outlook for
improved foundations for counseling is favorable. It will be enormously
enhanced as procedures are developed that might make possible positive
recognition of those who are asymptomatic heterozygotes for specified
undesirable genes. As medical euphonies becomes increasingly successful,
it will become increasingly important that genetic counseling be universally
practiced. Otherwise, in a few generations, the ethic that guides medical
practice will have seriously damaged the heritage of countless previous
generations. Having thwarted the historical process of natural selection
against such disadvantageous genes, civilization must provide an acceptable
substitute.
The possibility has been discussed that the great insights of molecular
biology may make it possible, in the future, to replace specific undesirable
genes in a person's cells with desirable ones brought in from the outside.
Several strategies are available, based largely upon understanding of the
mechanisms of viral infection. However, many biologists think that the
prospects for such "genetic surgery" are doubtful in the foreseeable future.
Even if succesful, this would probably simply be a more sophisticated
euphonic technique. While there is some possibility that appropriate, de-
sirable genes might, one day, be introduced into body cells, it seems unlikely
that the new genes could be so inserted into appreciable numbers of germ
cells.
Representative terms from entire chapter:
birth rates
