Download The Future of Evolution, Norman Myers

GUEST ESSAY
The Future of Evolution
Norman Myers
Norman Myers is a tropical ecologist and international consultant
in environment and development, with emphasis on
conservation of wildlife species and tropical forests. His research
and consulting have taken him to 80 countries. A leading
environmental expert, he has consulted for many development
agencies and research organizations, including the U.S. National
Academy of Sciences, the World Bank, the Organization for Economic Cooperation
and Development, UN agencies, and the World Resources Institute. Among his many
publications (see Further Readings on the website for this book) are The Primary
Source: Tropical Forests and Our Future (1992), Ultimate Security: The
Environmental Basis of Political Security (1996), Perverse Subsidies (with Jennifer
Kent, 2001), and The New Consumers: The Influence of Affluence on the
Environment (with Jennifer Kent, 2004).
Human activities have brought the earth to a biotic crisis. Many biologists have
commented that this crisis will result in the loss of large numbers of species, possibly
25–50%, within the lifetime of students reading this book. However, surprisingly few
biologists have recognized that in the longer term these extinctions will impoverish
evolution’s course for several million years.
The future of evolution should be regarded as one of the most challenging
issues humankind has ever encountered because currently we are the world’s
greatest evolutionary force. We are conducting a planet-scale experiment, with little
clue as to how it might turn out, except that it will prove irreversible and could
severely reduce human well-being. We could get by without half of all mammals and
other vertebrates. But if we lost half of all insects with their pollinating functions, let
alone their many other ecological services, we would be in trouble in the first cropgrowing season.
In addition, the mass depletion or extinction under way is the biggest of our
environmental problems in terms of the duration of its impact and the numbers of
people to be affected. All other environmental problems are potentially reversible. If
Copyright ©2005 Brooks/Cole, a division of Thomson Learning, Inc. Thomson Learning
is a trademark used herein under license.
we wanted to clean up acid deposition, we could do it within a few decades. We could
push back the deserts, restore topsoil, and allow the ozone layer to be repaired
within a century or so. We could probably restore climate stability in the wake of
global warming within a thousand years. But once a species is gone, it is gone for
good.
Of course, in the long run evolution will generate replacement species with
numbers and variety to match today’s. But that is likely to take millions of years. We
are witnessing severe reduction if not elimination of entire sectors of biomes, notably
tropical forests, coral reefs, and wetlands, all of which may have served as
powerhouses of evolution—centers of new speciation—in the prehistoric past.
Suppose, as has happened after the mass extinctions and depletions of the
prehistoric past, that the bounce-back period lasts at least 5 million years. This
would be 20 times longer than humans have been around as a species. Suppose that
the average number of people on the earth during that period is 2.5 billion people, as
opposed to the 6.5 billion today. Then the total number of people affected by what
we do (or don’t do) to protect the biosphere during the next few decades will be
about 500 trillion, in contrast with the 50 billion people who have ever existed! In
short, we are engaged in by far the biggest decision ever made by one human
community on behalf of future human communities. Yet the issue is almost entirely
disregarded, whether scientifically, ethically, or otherwise. How often do you hear
leading scientists or ethicists even mention the issue?
Despite our gross ignorance of what lies ahead, we can venture a few
hypotheses about what is likely to happen as a result of the projected extinction
spasm:

A temporary outburst of speciation. As large numbers of niches are vacated,
there could be an outburst of speciation, although not nearly enough to match the
extinction spasm.

A proliferation of opportunistic species such as cockroaches , rats, flies, and
others that prosper when new niches open up. This proliferation will be enhanced by
the likely elimination of species that naturally control such opportunistic species.

An end to large vertebrates.

An end to speciation of large vertebrates. Even if larger vertebrates were to
survive the extinction spasm ahead, our largest protected areas will prove far too
small for further speciation of elephants, rhinoceroses, apes, bears, and the bigger
cats, among other large vertebrates.
Copyright ©2005 Brooks/Cole, a division of Thomson Learning, Inc. Thomson Learning
is a trademark used herein under license.
What does this imply for our conservation efforts? By far the predominant
strategy of conservationists is to save as many species as possible. But we now need
to safeguard evolutionary processes as well. A prime goal is to look out especially for
endemic species (found only in a particular place) or species confined to small
habitats. Examples include the California condor, the black-footed ferret, the giant
panda, and the gorilla.
However, the fossil record shows that endemic species often turn out to be
evolutionary dead ends: Generally they do not throw off new species. So should we
shift our conservation priority from endemic species to broader-ranging species in
the hope that they have more genetic variability and thus more of a diversified
resource stock on which natural selection can work its creative impact?
Similarly, should we devote more attention to protecting the evolutionary
powerhouses such as the forests, coral reefs, and wetlands of the tropics? All these
are in dire trouble and may be all but eliminated within a few decades. Do they
deserve preferential treatment ahead of, say, temperate-zone woodlands and
grasslands and boreal forests with their lack of species, ecological complexity, and
evolutionary potential?
If within your lifetime we allow the current biotic crisis to proceed unchecked
(which is what the recent record suggests), it is possible that your children will ask
you a key question: “When the evolutionary debacle was becoming all too plain at
the start of the 21st century, what did you do to help ward off this disaster?” I hope
you will engage yourself in dealing with this crucial issue.
Critical Thinking
1. Do you agree or disagree with the thesis of this essay? Explain.
2. If you agree, list three things you could do to help prevent the outcomes
described in this essay.
Copyright ©2005 Brooks/Cole, a division of Thomson Learning, Inc. Thomson Learning
is a trademark used herein under license.