基本介紹
- 中文名：太空生物學
- 外文名：Astrobiology,Exobiology
- 分類：交叉學科
- 研究對象：生命的起源、進化、分布和未來
概述,英文介紹,
概述
太空生物學（Astrobiology,Exobiology）是研究生物和外空間物體的相互作用的科學。是研究關於地球以及整個宇宙的生命的起源、進化、分布和未來的科學。其中要回答的最基本的問題就是：生命是怎樣起源的？空間生命的未來會怎樣？我們是宇宙中的唯一生命體嗎？太空生物學是一個新興而迅速發展的領域，吸引了大量的政府基金和優秀的科學家。2003年10月15日我國“神舟”五號載人飛船成功發射以及隨後的安全著陸，標誌著中國在攀登世界科技高峰中，邁出了有重大歷史意義的一步。中華民族在航天事業上的發展必將翻開新的篇章。
英文介紹
Astrobiology, the transcendent science: the promise of
astrobiology as an integrative approach for science
and engineering education and research
James T Staley
Astrobiology is rapidly gaining the worldwide attention of
scientists, engineers and the public. Astrobiology’s captivation is
due to its inherently interesting focus on life, its origins and
distribution in the Universe. Because of its remarkable breadth as
a scientific field, astrobiology touches on virtually all disciplines in
the physical, biological and social sciences as well as
engineering. The multidisciplinary nature and the appeal of its
subject matter make astrobiology ideal for integrating the
teaching of science at all levels in educational curricula. The
rationale for implementing novel educational programs in
astrobiology is presented along with specific research and
educational policy recommendations.
Addresses
Department of Microbiology, NSF Astrobiology IGERT Program,
University of Washington, Box 357242, Seattle, WA 98195, USA
Current Opinion in Biotechnology 2003, 14:347–354
This review comes from a themed issue on
Science policy
Edited by Rita R Colwell
0958-1669/03/$ – see front matter
2003 Elsevier Science Ltd. All rights reserved.
DOI 10.1016/S0958-1669(03)00073-9
Abbreviations
NAI NASA Astrobiology Institute
NASA National Aeronautics and Space Administration
NSF National Science Foundation
SETI search for extraterrestrial intelligence
Introduction
This article introduces the multidisciplinary field of astrobiology,
which bridges the gap between the biological and
physical sciences and engineering. In addition, recommendations
are made for astrobiology to serve as an
alternative model for teaching science and engineering
at all levels of education including primary, secondary,
undergraduate and graduate students. I am writing this
article largely based upon the experience that my colleagues
and I have had in developing a PhD program in
astrobiology at the University of Washington.
What a difference a word makes
For four decades the National Aeronautics and Space
Administration (NASA) sponsored a science program on
exobiology, a term which, by definition, refers to the
study of life outside Earth. Excluding Earth and earthlings
seems inappropriate for at least three reasons. First, it
is ironic to disregard Earth, because it is the only place so
far known in the Universe where life actually exists.
Second, exobiology implies that there is something very
different and strange about creatures from other planetary
bodies. Why shouldn’t all living matter in the Universe
share common properties in the same sense as other
matter? Third, the study of life on Earth, including its
evolution and diversity, provides valuable clues and lessons
for the exploration of other worlds that may harbor
life. After all, if we cannot understand life, its origins and
its limits on Earth, how can we possibly begin to identify
life and efficiently study it elsewhere?
The perception of scientists and lay people has changed
since NASA introduced the term astrobiology, because
it optimistically embraces the study of all life in the
Universe, including life on Earth. The introduction of
the term astrobiology coincided with NASA’s establishment
in 1998 of the NASA Astrobiology Institute (NAI),
which now encompasses about a dozen universities and
research centers at NASA and elsewhere (http://www.nai.
arc.nasa、gov). In the five years since the NAI began as
a virtual institute, an international effort has linked its
astrobiology program to those of several other countries.
These include Spain (Centro de Astrobiologia), the United
Kingdom (UK Astrobiology Forum and Network), France
(Groupement de Recherche en Exobiologie), Europe
(The European Exo/Astrobiology Network Association)
and Australia (Australian Centre for Astrobiology).
Why is astrobiology so appealing?
How is it that astrobiology has captured the curiosity,
fascination and admiration of so many? Surely much of its
appeal has to do with the great metaphysical questions of
astrobiology. Where did we come from? How does life
begin and evolve? What is life’s future? Does life occur
elsewhere in the universe?
This young and vigorous field holds great expectations
that these questions can and will be answered. Herein lies
the appeal of astrobiology. Not only is the subject matter
of broad interest to virtually all of us, it is basic to our
perception of the world in which we live. Furthermore,
scientists are sanguine about our ability to answer at least
some of these questions in the foreseeable future. So, it is
not surprising that the air bristles with excitement and
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anticipation at astrobiology meetings as scientists report
how they are unraveling the mysteries of life, its tenacity,
fragility, distribution and origins.
The transcendent nature of astrobiology
Astrobiology is remarkable in its extreme breadth and
therefore its potential for multidisciplinary education
and research. It touches on virtually all fields of science
and engineering. As a result it is perhaps unique among all
disciplines. Astrobiology is unlike, for instance, biology
which is exclusively centred on the study of all aspects of
life on Earth. Astrobiology, by contrast, considers questions
that transcend our planetary boundary. When biologists
ask the question ‘What is life?’ they are constrained
by the range of life forms on Earth. However, when the
astrobiologist asks the same question, all boundaries are
removed. The astrobiologist is no longer confined to life
on Earth, but is forced to conjure possibilities beyond the
requirements of water and the DNA! RNA! protein
dogma. Indeed, imagination is the only limitation to the
astrobiologist’s thinking, although it is a severe one. To
test your own imagination, contemplate the question
‘What is life?’ and propose one or two truly alternative
life styles to that which we know so well.
A special multidisciplinary challenge for astrobiology
relates to the dating of early events on Earth and provides
another example of its transcendent nature. Geologists
working with paleontologists provided us with the
Geological Timetable during the last half of the 20th
century. From this effort, much was learned about the
past 600 million years of animal and plant evolution.
However, little is known about early evolution, that is,
from the Precambrian Eon after Earth’s formation about
4.5 billion years ago until 600 million years ago. Our only
hope to uncover this information is through the mutual
efforts of geologists, micropaleontologists, microbiologists
and phylogeneticists. Fossils alone cannot answer
the important questions about the order in which processes
such as methanogenesis and sulfate reduction
occurred, because microbial fossils are too simple. Chemical
biomarkers for processes and specific microbial
groups are needed in conjunction with phylogenetic
analyses. Already astrobiologists from the various disciplines
are talking with one another about resolving this
issue through multidisciplinary efforts.
So, not only does astrobiology provide genuine appeal to
all, but it is perhaps unique in its transcendence of
science. It encompasses aspects of biology, astronomy,
physics, planetary sciences, chemistry and geology as well
as the social sciences. Example topic areas in astrobiology
are given in Box 1.
Interdisciplinary astrobiology research
Much of the exciting research in astrobiology lies at the
interface between two or more disciplines. For example,
microorganisms are intimately involved in rock weathering
processes. From an astrobiological perspective,
biological weathering processes leave ‘signatures of life’
such as specific biological compounds or microbial fossils
that could be used to identify life on rocks from other
planetary bodies such asMars. The traditional training of
geologists and microbiologists does not prepare PhD
graduates to study these geobiological activities by themselves;
however, in astrobiology, scientists work together
in designing and testing hypotheses and thereby expanding
our understanding of fundamental but poorly studied
processes.
In our astrobiology PhD program at the University of
Washington, we have seen examples of interdisciplinary
work that have resulted in unique perspectives. It is
noteworthy in this regard that it is not always the faculty
who have made these breakthroughs, but it is often our
PhD students. One example of this is work carried out by
an astronomy student, John Armstrong, and a biology
student, Llyd Wells, who have worked with an astronomy
faculty member, Guillermo Gonzalez. They proposed
that the Moon, as ‘Earth’s attic’, probably contains
rocks with microbial fossils and other signatures of life
from Earth that were ejected to the Moon as it drifted
away from Earth after its formation. These fossils would
be well preserved, because they have not been exposed
to weathering and tectonic processes on Earth. These
rocks are therefore likely to contain geochemical and
fossil evidence that may tell us much about early Earth
history [1]. In a second paper, they suggest that, had a
major sterilizing impact occurred on Earth following the
evolution of life, rocks subsequently ejected from the
Moon by an impact event could have been brought back
to Earth to re-seed it [2]. These papers are having a
major influence on NASA’s thinking concerning the
possibility of launching amission to theMoon to retrieve
early Earth rocks.
Another example of interdisciplinary collaboration involves
two of our faculty members. Peter Ward and Don
Brownlee, a paleontologist and an astronomer, respectively,
have collaborated in writing two recent provocative
books on astrobiology, ‘Rare Earth’ and ‘The Life and Death
of Planet Earth’ (Box 2).
Box 1 Example topic areas in astrobiology.
Star birth, death and recycling of elements
Formation of planetary systems
Origin and evolution of life
Search for extraterrestrial biosignatures
Habitable planets and satellites within and beyond our solar system
Earth’s early geosphere, hydrosphere and atmosphere
Earth’s early biosphere
Mass extinctions and diversity of life
Fossil and geochemical evidence of early life
Life in extreme environments
Planetary protection
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Astrobiology as an exciting new field for
research
In this brief article, it is not possible to provide detailed
information about ongoing astrobiology research that is
changing our views of our world and the possibility of life
elsewhere. What I have done is to ask my colleagues to
submit references of recent articles that they believe
have made major contributions in their fields. I have
grouped these below under various astrobiology subject
headings along with brief descriptions of their content
and significance. This is not meant to be a complete
listing, but should provide an indication of the vitality
and breadth of the field. An excellent general reference
on astrobiology has been written by Des Marais and
Walter [3].
Extreme environments and extremophiles
Several groups have looked at extreme environments on
Earth, protracting their findings to possible conditions on
other planetary bodies. For example, Doran and colleagues
[4] report on Lake Vida, one of the largest lakes in
the McMurdo Dry Valleys of Antarctica, which was previously
believed to be frozen solid. However, it now turns
out to contain a briny liquid (seven times seawater salinity,
temperature below 108C) beneath a 19 m thick ice
cover that has effectively isolated the brine for about 2800
years. The ice cover contains microbial populations that
are metabolically active upon thawing. The physical
features and geological history of the lake suggest it
may be an analog of the last vestige of an ancient Martian
aquatic ecosystem.
Similarly, Kelley and coworkers [5] describe a new class
of marine hydrothermal system hosted on peridotites.
The field hosts at least 30 active and inactive 30–60 m
tall carbonate chimneys that vent fluids at 40–758C with
pH values of 9–10. The chimneys harbor dense and
diverse microbial communities. Because this system is
hosted in peridotites, it is very reducing and associated
with high pH fluids. It may be the best current analog
to hydrothermal systems that operated on early Earth
(Figure 1).
Other groups have investigated various environments,
including winter sea-ice [6] (Figure 2), active sulfide
chimneys [7,8], and the acidic, iron-rich red river, Rio
Tinto, in Southern Spain [9]. Together, these types of
studies have highlighted the harsh environments in which
life can exist and have helped scientists understand the
range of environments outside Earth that may harbor
microbial life.
Geological sciences
Sudbury in Ontario is the largest known and most important
bolide impact structure (astrobleme) on Earth, being
one of the first to be recognized and debated. Its many
geological features are exposed at the Earth’s surface, and
Box 2 Astrobiology book and journal list (since 2000).
Textbooks
Bennett J, Shostak S, Jakosky B: Life in the Universe. Boston:
Addison Wesley; 2003.
For introductory college courses for nonscience majors; stronger
on the physical sciences than biology
Goldsmith D, Owen T: The Search for Life in the Universe, 3rd Edn.
San Francisco: Benjamin Cummings; 2002.
For introductory college courses for nonscience majors; stronger
on the physical sciences than biology
Prather E, Offerdahl E, Slater T: Life in The Universe Activities
Manual. Boston: Addison-Wesley; 2003.
Student activities to accompany the textbook by Bennett et al.
Zubay G: Origins of Life on the Earth and in the Cosmos, 2nd Edn.
London: Harcourt; 2000.
Tutorial approach to the biochemistry of how life works and its origin
Popular books
Clark S: Life on Other Worlds and How to Find It. New York:
Springer-Praxis: 2000.
Darling D: Life Everywhere: the Maverick Science of Astrobiology.
New York: Basic Books; 2001.
Well-written; includes personalities of researchers
Darling D: The Extraterrestrial Encyclopedia: an Alphabetical
Reference to All Life in the Universe. Three Rivers; 2001.
deDuve C: Life Evolving: Molecules, Mind, and Meaning. Oxford UK:
Oxford University Press; 2002.
Nobelist argues for the inevitability of the emergence of life
Dick S: Life on Other Worlds: the 20th Century Extraterrestrial Life
Debate. Cambridge UK: Cambridge University Press; 2001.
Shorter, popular version of ‘The Biological Universe’ listed below
Fry I: The Emergence of Life on Earth: a Historical and Scientific
Overview. New Jersey: Rutgers University Press; 2000.
Excellent overview of past and current ideas on the origin of life
Grady M: Astrobiology. Washington: Smithsonian Institution Press; 2001.
Nice slim volume
Koerner D, Levay S: Here be Dragons: the Scientific Quest for
Extraterrestrial Life. Oxford UK: Oxford University Press; 2000.
Ward P: Rivers in Time: the Search for Clues to Earth’s Mass
Extinctions. Columbia: Columbia University Press; 2000.
Ward P, Brownlee D: Rare Earth: Why Complex Life is Uncommon in
the Universe. Copernicus, 2000.
Pioneering synthesis; astronomer and paleontologist argue that planets
with conditions for life more complex than single cells are
rare in the Universe
Ward P, Brownlee D: The Life and Death of Planet Earth: How the
New Science of Astrobiology Charts the Ultimate Fate of Our
World. New York: Henry Holt; 2003.
Wills C, Bada J: The Spark of Life: Darwin and the Primeval Soup.
Cambridge MA: Perseus; 2000.
Scholarly publications
Dick S: The Biological Universe: the Twentieth-Century
Extraterrestrial Life Debate and the Limits of Science.
Cambridge UK: Cambridge University Press; 2000.
The definitive historical study of the development over the 20th
century of ideas (both scientific and more popular, e.g. UFOs) on
extraterrestrial life, origin of life, exobiology and astrobiology
Horneck G, Baumstark-Khan C (Eds): Astrobiology: The Quest for the
Conditions of Life. New York: Springer; 2002.
Most chapters (by separate authors) are an outgrowth of a
workshop on astrobiology held in Germany; uneven coverage
Lemarchand G, Meech K (Eds): Bioastronomy ‘99: A New Era in
Bioastronomy. Proceedings of the Astronomical Society of the
Pacific Conference; Hawaii, USA, 2–6 August 1999. Vol. 213.
ASP, 2000.
Proceedings of a wide-ranging conference; strongest on the astronomy
Journals
Astrobiology. New York: Mary Ann Liebert, Inc.; (2001–).
International Journal of Astrobiology. Cambridge UK: Cambridge
University Press; (2002–).
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it is one of the world’s largest sources of nickel ore. The
Fe-Ni-Cu-S ore was not derived from the bolide, but
formed by processes induced by the impact. Naldrett [10]
has reviewed our current understanding of this site in an
article that illustrates the contribution of the geological
sciences to astrobiology.
Planetary and atmospheric science
Astronomers are beginning to discover planets beyond
Earth’s solar system and new models are being proposed
for their formation [11]. Data from the Hubble Space
Telescope provided the first direct detection of the atmospheric
composition of a planet orbiting a star outside our
solar system [12]. Sodium was found in the atmosphere
of a planet orbiting a yellow, Sun-like star called HD
209458, located 150 light-years away in the constellation
Pegasus. Although this particular planet is a gas giant like
Jupiter and unlikely to harbor life, the study demonstrated
that it is feasible to measure the chemical makeup
of extrasolar planetary atmospheres and to potentially
search for the chemical markers of life (such as O2)
beyond our solar system [13].
Recent evidence strongly supports the view that Mars has
water that has flowed in the recent past, supporting the
notionthat subsurface brinesmayexist [14].Bolideimpacts
in the past may have thawed frozen subsurface water
leading to temporary episodes of rain and flash floods [15].
Earth may have actually frozen over completely in its
past, a phenomenon referred to as ‘Snowball Earth’.
Hoffman and Schrag [16] have recently reviewed this
field and Warren et al. [17] discuss where surface life may
have survived during one of these remarkable events.
Until recently, atmospheric scientists explained how early
Earth could remain unfrozen even when the sun was 30%
less luminous because they believed the atmosphere had
high levels of the greenhouse gas, carbon dioxide. This
view has now changed as Pavlov et al. [18] showed how
biogenic methane in an early anoxic atmosphere could
have served as the key greenhouse gas. Catling et al. [19]
showed that the high methane concentration in the early
atmosphere could also explain the oxidation of the atmosphere:
ultraviolet light’s decomposition of methane to
hydrogen and its escape to space would have left Earth
more oxidized before biogenic oxygen production.
Early evolution
As surprising as it may seem microbiologists are still
discovering on Earth entirely new kingdoms ofmicrobial
life including representatives from each of the three
Figure 1
Several groups have looked at extreme environments on Earth, protracting their findings to possible conditions on other planetary bodies. Kelley and
coworkers [5] described a new class of marine hydrothermal system from the mid-Atlantic Ridge that is hosted on peridotites, which may be the
best current analog to hydrothermal systems that operated on early Earth. The figure shows a hydrothermal vent off the coast of Washington State.
The structures at this site vent at temperatures up to 3008C. Detailed analyses of one of the sulfide structures shows that they host dense and
diverse microbial communities. (The photograph is reproduced with kind permission from D Kelley.)
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domains, the Bacteria, Archaea and Eucarya. One example
is described in the recent paper of Huber et al. [20]
who reported an unexpected group of the Archaea,
known species of which parasitize other members of
the Archaea.
Much confusion still exists about the evolution of the first
organisms. Woese [21] considers the importance of horizontal
gene transfer on the evolution of early cellular life.
He proposed the ‘Darwinian Threshold’ as a seminal
period that separates early evolution in which horizontal
gene transfer dominated evolutionary processes from the
subsequent period in which evolution followed the vertical
inheritance of life as we now know it.
Although evidence indicates that many of the traits of the
Eucarya can be traced to the Bacteria and Archaea, until
recently tubulin genes have only been found in the
Eucarya, all species of which have them. However, this
too is no longer true; a bacterium that contains a- and
b-tubulin homologs has now been discovered [22].
Paleontology
Shen et al. [23] demonstrate the existence of microbial
sulfate reduction as early as 3.45 billion years ago, providing
the first evidence of a specific metabolism in
Earth’s evolutionary record. As this is typically a heterotrophic
metabolism in which organic matter is oxidized
anaerobically with sulfate, it implies that microbial ecosystems
were already quite diverse with complex trophic
webs and biogeochemical cycles. As sulfate reduction
requires sophisticated biochemical control, it further
implies that soon after the end of heavy meteorite bombardment
of the Earth, life was already quite advanced in
its cellular functions.
Considerable doubt has been cast on the claim that there
is carbon-isotopic evidence for life on Earth older than
3.85 Ga [24,25]. If correct, this claim would imply that
autotrophic organisms inhabited the Earth at the time of
the heavy meteorite bombardment and therefore that life
could have been widespread in the early solar system. Van
Zuilen et al. [24] argue that the observed carbon-isotope
fractionation is not biotic, but is instead the result of
metamorphic carbonate reduction to graphite. Fedo and
Whitehouse [25] argue that the host rock for this graphite
is an altered igneous rock and not a sedimentary banded
iron formation, so it should not be expected to host
biological remains.
Planetary protection and the search for
extraterrestrial intelligence
Astrobiologists are concerned about the biological contamination
of planetary bodies by life from elsewhere.
Figure 2
Sea-ice on Earth has become a model system in which to study planetary bodies such as Jupiter’s moon Europa, which has a frozen ocean that is
shown in close-up view. The texture of the ocean supports the view that there are large blocks of ice floating on a liquid ocean that may support
microbial life. (Figure reproduced with courtesy of the Jet Propulsion Laboratory at NASA/Caltech.)
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Rummel [26] has written an accessible review of the
history and state of planetary protection policy and implementation.
More specific issues, such as the handling and
quarantine of samples returned from elsewhere (e.g.
Mars), have been considered in some detail [27].
In part 1 of a comprehensive treatment of biological
transfer, Mileikowsky et al. [28] discuss the potential
for the natural transfer of microbes between solar system
bodies. This is based on knowledge that large impact
events (from comets or asteroids) occurring on one body
can propel significant quantities of material off a planetary
surface and into solar orbits that may intersect the orbits
of other bodies.
The search for extraterrestrial intelligence (SETI) continues
as one of the earliest endeavors that has attempted
to discover advanced life on other planetary bodies [29].
NASA’s astrobiology website contains links to the NAI
projects as well as an Astrobiology Roadmap that
describes research goals. Perhaps what is most remarkable
is that, during the past decade, this field has grown from a
small core of dedicated scientists to a large and impressive
group with many young scientists. With the emergence of
new technologies, such as genome sequencing and extrasolar
system planetary discovery techniques, our understanding
in all areas from molecular evolution to planetary
habitability is rapidly transforming our comprehension
of astrobiology.
Astrobiology’s promise for multidisciplinary
science education and research
Most educators agree there is a need to rethink science
and engineering education. Many of the traditional disciplines
seem to lack context in our modern world, at least
to many young scholars. By incorporating astrobiology
into a curriculum, the treatment of subject matter
changes. For example, consider the biology instructor
who is interested in teaching about the diversity of life.
A typical approach would be to discuss the different
species from each of the numerous animal groups and
how some are being threatened with extinction due to
habitat loss. In an astrobiology course the diversity issue
could be addressed in the context of mass extinctions,
such as, ‘What happened to the dinosaurs?’ The answer to
this question entails a discussion of biology, paleontology,
astronomy, physics (for dating fossils), evolution and
could be followed up by a discussion of the human-driven
mass extinction that is occurring now. Therefore, astrobiology
can provide a compelling way of integrating the
sciences in the classroom.
Also, from a pragmatic standpoint, the subject matter in
astrobiology is very flexible. It can be taught within the
structure of an entire science curriculum at one extreme,
or as a single course. Furthermore, astrobiology can be
taught to all educational levels and it serves as an engaging
outreach program to the public.
Because of the interest in astrobiology courses, several
books have recently been published, some of which could
serve as textbooks for courses at the undergraduate and
graduate levels (Box 2).
Policy recommendations for astrobiology
science education and research
PhD traineeship programs
Evidence from our University of Washington National
Science Foundation (NSF) Integrative Graduate Education
and Research Traineeship (IGERT) astrobiology
program (http://depts.washington、edu/astrobio/) indicates
that astrobiology can serve as an excellent subject area for
interdisciplinary PhD education in science and engineering.
Because astrobiology is such a broad and exciting
field of study in science, it should be promoted as a
curriculum in science education and research at the
doctoral level.
We recommend that NASA, NSF and other appropriate
federal agencies should provide support for the implementation
of PhD traineeship programs in science and
engineering education in astrobiology. This will develop
a unique group of scientists and engineers who will be
able to effectively communicate and collaborate with one
another. Furthermore, they will be able to subsequently
train university students in astrobiology and interdisciplinary
research.
Astrobiology students who receive PhD degrees will be
ideal candidates for the instruction of courses for doctoral
students interested in astrobiology. At this time there are
very few students. Even when more students graduate,
however, it should be recognized that they will not have
the in-depth experience to supervise students in PhD
courses and research in areas outside their own disciplinary
expertise, so a co-mentoring approach appears more
appropriate. Astrobiology students trained in our program
complete all of the necessary requirements in their major
department and, in addition, complete the requirements
for the astrobiology program. Therefore, they can compete
effectively for post-graduate opportunities with
others in their own area, but have the added experience
of working in a multidisciplinary training environment,
which, we believe, makes them better prepared for their
future careers.
Astrobiology PhD programs are likely to remain interdepartmental
for the foreseeable future. Although they
may eventually be accepted as departmental programs,
this seems premature now as it may actually detract from
the true vision of a cross-disciplinary field. Nonetheless, if
life is discovered elsewhere in our solar system or in
another planetary system, it could certainly lead to a need
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to train additional astrobiologists through university
departmental programs. In this sense, an astrobiology
training program could serve as a forerunner for the cadre
of scientists and engineers eventually needed.
The current NSF IGERT program is an excellent model
to use for development of a joint NASA-NSF or other
agency program, because of the importance it places on
integrative student training and support for development
of novel educational ideas.
Undergraduate university level
Astrobiology is currently amenable for the instruction of
undergraduate students in single courses. Textbooks are
available that may be used for that purpose if institutions
have faculty members who can teach in the various
subject areas.
Because astrobiology covers such a vast area, most instructors
will find it difficult to teach an entire course; however,
it could be team-taught by faculty from biology and the
physical sciences. Ultimately, as PhD scientists and engineers
are trained in astrobiology, they would become
ideal candidates to teach an entire course at the undergraduate
level.
Our recommendation for teaching astrobiology at the
undergraduate level is to provide support for training of
existing faculty at institutions that wish to develop astrobiology
courses or a curriculum. This could be handled by
supporting faculty study leaves to a university in which a
graduate level program in astrobiology is in place, as well
as at the various non-academic NAI institutions.
Primary and secondary education
Astrobiology is an exciting field that is ideal for teaching
science to students in secondary education. Some materials
are currently available for this such as Astro-Venture
for grades 5–8, at the NAI site mentioned previously, and
the SETI Institute high school curriculum (www.seti、org/
Welcome.html). However, there is a need to train teachers
and develop additional instructional materials. This
could be initiated with a trial period at primary and
secondary schools that wish to pursue this subject matter
in their science curriculum. Once this trial period is over,
say after five years, the concept could be evaluated and, if
appropriate, implemented.
To teach astrobiology at this level we recommend that
support is provided for workshops and course planning
sessions for scientists from universities with astrobiology
programs and science teachers of primary and secondary
school students. The goal of these workshops is to
develop trial curricula for teaching astrobiology at the
primary and secondary levels. It would also be necessary
to support the development of astrobiology courses and
appropriate educational materials (textbooks, videos,
websites, etc) that could be used for teaching primary,
secondary and undergraduate students interested in
science and engineering.
Conclusions
Recent advances in scientific knowledge from such disparate
areas as microbiology, astronomy, geochemistry,
paleontology, genomics, planetary science and molecular
evolution have culminated in the formation of the new
field of astrobiology. Astrobiology, which transcends virtually
all of the sciences, aims to answer the great questions
about the origin of life and its distribution and
evolution in the Universe. Astrobiology has quickly
ascended to international prominence as a novel multidisciplinary
and integrated scientific research area.
Because of its innately interesting subject material, astrobiology
is ideally suited for teaching science from kindergarten
to the graduate level. Now is the time to
implement astrobiology into educational programs in
the form of new courses and new curricula. In order to
accomplish this goal, governmental resources will be
needed to train teachers and develop appropriate instructional
guidelines and materials.
Acknowledgements
I want to thank my colleagues at the University of Washington who have
made suggestions and provided some of the references mentioned,
especially Roger Buick, David Catling, Eric Cheney, Jody Deming,
Deborah Kelley, Marsha Landolt, Thomas Quinn, Steve Warren and Llyd
Wells. In addition, I wish to thank David Morrison who provided the book
listing and Woodruff Sullivan III who provided book annotations. Also
thanks to Rosalind Grymes and John Rummel for their excellent
suggestions, most of which I have adopted. I am also grateful to the NSF
IGERT and NASA NAI programs for providing support for my laboratory’s
research in astrobiology.
References and recommended reading
Papers of particular interest, published within the annual period of
review, have been highlighted as:
of special interest
of outstanding interest
1.
Armstrong J, Wells L, Gonzalez G: Rummaging through Earth’s
attic for remains of ancient life. Icarus 2002, 160:183-196.
This paper suggests that the moon may contain fossils of early Earth
organisms in rocks that were ejected to the moon by impacts.
2.
Wells L, Armstrong J, Gonzalez G: Reseeding Earth by impacts of
returning ejecta during the late heavy bombardment. Icarus: in
press.
Since the moon probably received ejecta from early Earth, returning
ejecta from the moon could have re-inoculated the Earth, which might
have been sterilized by large impacts.
3.
Des Marais D, Walter M: Astrobiology: exploring the origins,
evolution, and distribution of life in the Universe. Annu Rev Ecol
Systems 1999, 30:397-420.
Comprehensive review article with 100 citations of technical articles.
4. Doran P, Fritsen C, McKay C, Priscu J, Adams E: Formation and
character of an ancient 19-m ice cover and underlying trapped
brine in an ‘ice-sealed’ east Antarctic lake. Proc Natl Acad Sci
USA 2003, 100:26-31.
5.
Kelley D, Karson I, Blackman D, Fruh-Green D, Gee J, Butterfield D,
Lilley M, Olson E, Schrenk M, Roe K: An off-axis hydrothermal
field discovered near the Mid-Atlantic Ridge at 308N.
Nature 2001, 412:145-149.
This paper announces the discovery and describes the nature of the novel
‘Lost City’ hydrothermal vent system near the mid-Atlantic ridge.
Astrobiology, the transcendent science Staley 353
www.current-opinion、com Current Opinion in Biotechnology 2003, 14:347–354
6.
Krembs C, Deming J, Junge K, Eicken H: High concentrations of
exopolymeric substances in wintertime sea ice: implications
for the polar ocean carbon cycle and cryoprotection of
diatoms. Deep-Sea Res 2002, 49:2163-2181.
This study of winter sea-ice cores shows that the ice is filled throughout
with high concentrations of exopolymeric substances (EPS). At winter-ice
temperatures to as low as –208C, EPS were observed to protect organisms
within the ice against physical damage by encroaching ice crystals.
7. Schrenk M, Kelley D, Delaney J, Baross J: Incidence and diversity
of microorganisms within the walls of an active deep-sea
sulfide chimney. Appl Environ Microbiol: in press.
A comprehensive, up-to-date treatment of the diversity of life within
active sulfide chimneys. Fluorescence in situ hybridisation, 16S rDNA
sequences and cell count data are provided in several transects/zones
across the wall of a 3008C chimney from the Mothra Hydrothermal Field.
8.
Kelley D, Baross J, Delaney J: Volcanoes, fluids, and life in
submarine environments. Annu Rev Earth Planetary Sci 2002,
30:385-491.
This major review paper looks at processes in the mantle to the hydrosphere
in the context of impacts on microbial communities. Much of the
information is directly relevant to astrobiological questions concerning
the flux of volatiles, heat sources and linkages to microbial processes.
This paper is being used by numerous upper undergraduate and graduate
classes in a textbook fashion.
9. Zettler L, Gomez F, Zettler E, Keenan B, Amils R, Sogin M:
Eukaryotic diversity in Spain’s river of fire. Nature 2002, 417:137.
DNA extracted from the acidic, iron-rich red river, Rio Tinto, in Southern
Spain showed that 60% of its biomass is contributed by eukaryotic
microorganisms. 18S rDNA sequencing indicated this extreme environment
contains a surprising diversity of eukaryotic microorganisms.
10. Naldrett A: Presidential address: from impact to riches:
evolution of geological understanding as seen at Sudbury,
Canada. GSA Today 2003, 13:4-9.
11.
Mayer L, Quinn T, Wadsley J, Stadel J: Formation of giant planets
by fragmentation of protoplanetary disks. Science 2002,
298:1756-1759.
This planet formation article is causing a paradigm shift in the way we
think of planet formation and has implications for the ubiquity of planetary
systems.
12.
Charbonneau D, Brown T, Noyes R, Gilliland R: Detection of an
extrasolar planet atmosphere. Astrophys J 2002, 568:377.
This is the first report of an atmosphere of an extra-solar system planet.
13. Des Marais D, Harwit M, Jucks K, Kasting J, Lin D, Lunine J,
Schneider J, Seager S, Traub W, Woolf N: Remote sensing of
planetary properties and biosignatures on extrasolar terrestrial
planets. Astrobiology 2002, 2:153-181.
14. Malin M, Edgett K: Evidence for recent ground water seepage
and surface runoff on Mars. Science 2000, 288:2330-2335.
15. Segura T, Toon O, Colaprete A, Zahnle K: Environmental effects
of large impacts on Mars. Science 2002, 298:1977-1980.
