Historian Frederick Jackson Turner’s famous 1893 premise of the “significance
of the frontier in American history” argued that the struggle to conquer
the vast American continent — with its unique mixture of challenge and
opportunity — had been crucial in the formation of the American character.
He also declared that this frontier was gone. Even if you accept Turner’s
thesis (and many historians don’t), it is reasonable to ask what happens
when frontiers vanish or change — when the opportunities and challenges
are different or are no more.
Paleontology underwent a major expansion of theoretical frontiers over the last
quarter of the 20th century, resulting in the birth of modern paleobiology.
But despite that growth and the continuing popularity of dinosaurs among the
general public, academic paleontology was also widely viewed as a field in decline
among the geosciences, due mostly to the apparently irreversible retrenchment
of the use of fossils to date rocks in the search for petroleum. In November
1993, I felt compelled to defend on this very page the indispensability of paleontology.
A lot has changed since then. Through a combination of new technology, new fossils
and theoretical refinement, paleontology is once again in the midst of a ferment
of new ideas and opportunities, as well as challenges. A hypothetical “dream
team” of paleontologists for the next decade or two would come from a number
of fields.
Astrobiology — once only science fiction — for example, is now a large
part of the motivation for the most talked-about science story of 2004 and the
proposed future for manned space flight. The success of the rovers Spirit and
Opportunity in finding evidence for liquid water formerly on Mars has laid the
groundwork, and it is entirely plausible that within the careers of present
researchers, we will be examining fossils from Mars. In the meantime, paleontologists
will continue to play a major role in laying out the environmental conditions
in which life might have arisen on other worlds.
Back on Earth, we have yet to synthesize a coherent theory of how ecology “matters”
to long-term evolutionary change. Once we better understand that connection,
we will better be able to understand diversity changes at critical points of
biological “turnover” (episodes of both origination and extinction)
throughout time, including the Cambrian Explosion. Fueled by new fossil discoveries,
new paleoenvironmental data, and new insights from developmental biology, understanding
this burst in diversity 545 million years ago is the single hottest field in
paleontology right now and shows no sign of cooling off any time soon.
Paleontologists are also increasingly interfacing with life scientists, linking
developmental biology to evolutionary biology. This interface — known as
“evo-devo” — is a major locus of current activity on classical
paleontological topics like the Cambrian Explosion and the origin of the phyla
and one of the great growth fields in paleontology today. In its focus on the
role of internal “constraints” in evolution, it is also likely the
ultimate destination of much of Stephen J. Gould’s legacy.
Paleontologists, of course, are students of the past, but we are also increasingly
being seen as useful prognosticators of the present and future. In the early
1980s, E.O. Wilson and a few others first began to compare extinctions going
on today with those of the geologic past. Few took the comparisons seriously.
Now the “sixth extinction” is a common term for the current biodiversity
crisis, and it is widely appreciated that paleontology has real insights to
offer to its understanding and remediation. What Karl Flessa has usefully called
“conservation paleobiology” includes studies as diverse as recovery
from mass extinction and paleoecology. The Shifting Baselines initiative (www.shiftingbaselines.org),
is providing stark warnings of our impending environmental degradation and resulting
descent into a world resembling the Proterozoic — a world of “slime,”
devoid of complex life.
Biology is also contributing to paleontology through the explosion of information
made possible by genetic sequencing. Paleontology will not only continue to
benefit from having molecular family trees of particular groups, but it also
will continue to be essential for establishing the timing of events of molecular
evolution and for putting family trees based only on living taxa into larger
evolutionary contexts. Among my graduate students, it is a popular parlor game
to imagine what we (and especially they) will all be doing when “everything
is sequenced.” They need not worry: Integrating fossils and molecules will
be both a major challenge and an enormous opportunity for paleontology for the
foreseeable future.
Although it has been talked about for many years, we are now seemingly on the
threshold of a true cyber-infrastructure for paleontology. Initiatives
like CHRONOS, the Paleobiology Database, NMITA (Neogene Marine Biota of Tropical
America), the Paleontology Portal and interconnected collections databases are
no longer demonstration projects and have real potential to produce important
insights in the next few years. The work of the Paleobiology Database group,
for example, is reevaluating the history of the diversity in the seas over the
past 540 million years, which has been arguably one of the dominant topics in
paleobiology over the past 25 years (see story, page 28, "25 Years of Mass
Extinctions and Impacts").
Meanwhile, the geosciences in general continue to move toward the notion of
a global, integrated view of Earth as a set of interacting systems. A number
of geoscience departments have accordingly embraced “global change”
or “earth systems science” as new focuses of their research and efforts
to increase undergraduate majors. These programs are major opportunities for
paleontology: You simply cannot have a program in these areas without including
an understanding of the role of life and its history.
The frontiers of paleontology are once again spread far and wide across the
landscape. The coming years have every sign of being a time of excitement, discovery
and intellectual ferment along our stretch of these new unexplored continents.
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