Planetary Systems and the Origins of Life

by Edited by Ralph Pudritz , Paul Higgs , Jonathon Stone

• ISBN13: 9780521875486
• ISBN10: 052187548X
• Edition: 1st
• Format: Hardcover
• Copyright: 2007-12-24
• Publisher: Cambridge University Press

Summary

Several major breakthroughs in the last decade have helped contribute to the emerging field of astrobiology. Focusing on these developments, this fascinating book explores some of the most important problems in this field. It examines how planetary systems formed, and how water and the biomolecules necessary for life were produced. It then focuses on how life may have originated and evolved on Earth. Building on these two themes, the final section takes the reader on a search for life elsewhere in the Solar System. It presents the latest results of missions to Mars and Titan, and explores the possibilities of life in the ice-covered ocean of Europa. This interdisciplinary book is an enjoyable overview of this exciting field for students and researchers in astrophysics, planetary science, geosciences, biochemistry, and evolutionary biology. Colour versions of some of the figures are available at www.cambridge.org/9780521875486.

Author Biography

Ralph Pudritz is Director of the Origins Institute and a Professor in the Department of Physics and Astronomy at McMaster University Paul Higgs is Canada Research Chair in Biophysics and a Professor in the Department of Physics and Astronomy at McMaster University Jonathon Stone is Associate Director of the Origins Institute and SharcNet Chair in Computational Biology in the Department of Biology at McMaster University

Table of Contents

List of contributors	p. xi
Preface	p. xv
Planetary systems and the origins of life	p. 1
Observations of extrasolar planetary systems	p. 3
Introduction	p. 3
RV detections	p. 4
Transit detections	p. 7
Properties of the extrasolar planets	p. 10
Other methods of detection	p. 14
Future prospects for space missions	p. 16
Acknowledgements	p. 17
References	p. 17
The atmospheres of extrasolar planets	p. 21
Introduction	p. 21
The primary eclipse	p. 21
The secondary eclipse	p. 23
Characteristics of known transiting planets	p. 25
Spectroscopy	p. 27
Model atmospheres	p. 30
Observations	p. 32
Future missions	p. 35
Summary	p. 37
References	p. 38
Terrestrial planet formation	p. 41
Introduction	p. 41
The formation of planetesimals	p. 42
The growth of protoplanets	p. 43
The growth of planets	p. 47
The origin of the Earth-Moon system	p. 52
Terrestrial planets and life	p. 52
Summary	p. 56
Acknowledgements	p. 57
References	p. 57
From protoplanetary disks to prebiotic amino acids and the origin of the genetic code	p. 62
Introduction	p. 62
Protoplanetary disks and the formation of planet systems	p. 63
Protoplanetary disks and the formation of biomolecules	p. 68
Measurements and experiments on amino acid synthesis	p. 71
A role for thermodynamics	p. 73
The RNA world and the origin of the genetic code	p. 76
How was the genetic code optimized?	p. 80
Protein evolution	p. 82
Summary	p. 84
Acknowledgements	p. 84
References	p. 84
Emergent phenomena in biology: the origin of cellular life	p. 89
Introduction	p. 89
Defining emergence	p. 89
Emergence of life: a very brief history	p. 90
The first emergent phenomena: self-assembly processes on the early Earth	p. 91
Sources of amphiphilic molecules	p. 92
The emergence of primitive cells	p. 95
Self-assembly processes in prebiotic organic mixtures	p. 100
Emergence of membrane functions	p. 101
Emergence of growth processes in primitive cells	p. 103
Environmental constraints on the first forms of life	p. 105
Acknowledgements	p. 106
References	p. 106
Life on Earth	p. 111
Extremophiles: defining the envelope for the search for life in the universe	p. 113
Introduction	p. 113
What is an extremophile?	p. 114
Categories of extremophiles	p. 115
Environmental extremes	p. 115
How do they do it?	p. 123
Examples of extreme ecosystems	p. 125
Space: new categories of extreme environments	p. 126
Life in the Solar System?	p. 127
Conclusions	p. 130
Acknowledgements	p. 131
References	p. 131
Hyperthermophilic life on Earth - and on Mars?	p. 135
Introduction	p. 135
Biotopes	p. 136
Sampling and cultivation	p. 138
Phylogenetic implications	p. 139
Physiologic properties	p. 141
Examples of recent HT organisms	p. 143
References	p. 147
Phylogenomics: how far back in the past can we go?	p. 149
Introduction	p. 149
The principles of phylogenetic inference	p. 149
Artefacts affecting phylogenetic reconstruction	p. 152
Strengths and limitations of phylogenomics	p. 155
The importance of secondary simplification	p. 160
The tree of life	p. 164
Frequent strong claims made with weak evidence in their favour	p. 167
Conclusions	p. 171
Acknowledgements	p. 171
References	p. 172
Horizontal gene transfer, gene histories, and the root of the tree of life	p. 178
Introduction	p. 178
How to analyse multigene data?	p. 179
What does the plurality consensus represent? Example of small marine cyanobacteria	p. 182
Where is the root of the 'tree of life'?	p. 183
Use of higher order characters: example of ATPases	p. 185
Conclusions	p. 188
Acknowledgements	p. 188
References	p. 188
Evolutionary innovation versus ecological incumbency	p. 193
The Ediacaran world	p. 193
Preservational context	p. 194
Vendobionts as giant protozoans	p. 195
Kimberella as a stem-group mollusc	p. 198
Worm burrows	p. 202
Stability of ecosystems	p. 203
The parasite connection	p. 204
Conclusions	p. 207
Acknowledgements	p. 208
References	p. 208
Gradual origin for the metazoans	p. 210
Introduction	p. 210
Collagen as a trait tying together metazoans	p. 211
The critical oxygen concentration criterion	p. 212
The Burgess Shale fauna: a radiation on rocky ground	p. 213
Accumulating evidence about snowball Earth	p. 215
North of 80[degree]	p. 216
Conclusion	p. 219
Acknowledgements	p. 219
References	p. 219
Life in the Solar System?	p. 223
The search for life on Mars	p. 225
Introduction	p. 225
Mars today and the Viking search for life	p. 227
Search for second genesis	p. 229
Detecting a second genesis on Mars	p. 235
Conclusions	p. 238
References	p. 238
Life in the dark dune spots of Mars: a testable hypothesis	p. 241
Introduction	p. 241
History	p. 241
Basic facts and considerations about DDSs	p. 243
Challenges and answers	p. 250
Partial analogues on Earth	p. 255
Discussion and outlook	p. 257
Acknowledgements	p. 258
References	p. 258
Titan: a new astrobiological vision from the Cassini-Huygens data	p. 263
Introduction	p. 263
Analogies between Titan and the Earth	p. 264
A complex prebiotic-like chemistry	p. 271
Life on Titan?	p. 278
Conclusions	p. 280
Acknowledgements	p. 281
References	p. 282
Europa, the ocean moon: tides, permeable ice, and life	p. 285
Introduction: life beyond the habitable zone	p. 285
The surface of Europa	p. 286
Tides	p. 295
The permeable crust: conditions for a European biosphere	p. 305
Acknowledgements	p. 309
References	p. 309
Index	p. 313
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