Table Of ContentThis page intentionally left blank
CambridgeAstrobiology
SeriesEditors
BruceJakosky,AlanBoss,FrancesWestall,DanielPrieur,andCharlesCockell
Booksintheseries:
1. PlanetFormation:Theory,Observations,andExperiments
EditedbyHubertKlahrandWolfgangBrandner
ISBN978-0-521-86015-4
2. FitnessoftheCosmosforLife:BiochemistryandFine-Tuning
EditedbyJohnD.Barrow,SimonConwayMorris,StephenJ.Freeland,and
CharlesL.Harper,Jr.
ISBN978-0-521-87102-0
3. PlanetarySystemsandtheOriginsofLife
EditedbyRalphPudritz,PaulHiggs,andJonathonStone
ISBN978-0-521-87548-6
PLANETARY SYSTEMS AND
THE ORIGINS OF LIFE
RALPHPUDRITZ,PAULHIGGS,JONATHONSTONE
McMasterUniversity,Canada
CAMBRIDGEUNIVERSITYPRESS
Cambridge, New York, Melbourne, Madrid, Cape Town, Singapore, São Paulo
Cambridge University Press
The Edinburgh Building, Cambridge CB28RU, UK
Published in the United States of America by Cambridge University Press, New York
www.cambridge.org
Information on this title: www.cambridge.org/9780521875486
© Cambridge University Press 2007
This publication is in copyright. Subject to statutory exception and to the provision of
relevant collective licensing agreements, no reproduction of any part may take place
without the written permission of Cambridge University Press.
First published in print format 2007
ISBN-13 978-0-511-36667-3 eBook (EBL)
ISBN-10 0-511-36667-1 eBook (EBL)
ISBN-13 978-0-521-87548-6 hardback
ISBN-10 0-521-87548-X hardback
Cambridge University Press has no responsibility for the persistence or accuracy of urls
for external or third-party internet websites referred to in this publication, and does not
guarantee that any content on such websites is, or will remain, accurate or appropriate.
Contents
Listofcontributors pagexi
Preface xv
PartI Planetarysystemsandtheoriginsoflife 1
1 Observationsofextrasolarplanetarysystems 3
ShayZucker
1.1 Introduction 3
1.2 RVdetections 4
1.3 Transitdetections 7
1.4 Propertiesoftheextrasolarplanets 10
1.5 Othermethodsofdetection 14
1.6 Futureprospectsforspacemissions 16
Acknowledgements 17
References 17
2 Theatmospheresofextrasolarplanets 21
L.JeremyRichardsonandSaraSeager
2.1 Introduction 21
2.2 Theprimaryeclipse 21
2.3 Thesecondaryeclipse 23
2.4 Characteristicsofknowntransitingplanets 25
2.5 Spectroscopy 27
2.6 Modelatmospheres 30
2.7 Observations 32
2.8 Futuremissions 35
2.9 Summary 37
References 38
vi Contents
3 Terrestrialplanetformation 41
EdwardW.Thommes
3.1 Introduction 41
3.2 Theformationofplanetesimals 42
3.3 Thegrowthofprotoplanets 43
3.4 Thegrowthofplanets 47
3.5 TheoriginoftheEarth–Moonsystem 52
3.6 Terrestrialplanetsandlife 52
3.7 Summary 56
Acknowledgements 57
References 57
4 Fromprotoplanetarydiskstoprebioticaminoacidsandthe
originofthegeneticcode 62
PaulG.HiggsandRalphE.Pudritz
4.1 Introduction 62
4.2 Protoplanetarydisksandtheformationofplanetsystems 63
4.3 Protoplanetarydisksandtheformationofbiomolecules 68
4.4 Measurementsandexperimentsonaminoacidsynthesis 71
4.5 Aroleforthermodynamics 73
4.6 TheRNAworldandtheoriginofthegeneticcode 76
4.7 Howwasthegeneticcodeoptimized? 80
4.8 Proteinevolution 82
4.9 Summary 84
Acknowledgements 84
References 84
5 Emergentphenomenainbiology:theoriginofcellularlife 89
DavidDeamer
5.1 Introduction 89
5.2 Definingemergence 89
5.3 Emergenceoflife:averybriefhistory 90
5.4 Thefirstemergentphenomena:self-assemblyprocesses
ontheearlyEarth 91
5.5 Sourcesofamphiphilicmolecules 92
5.6 Theemergenceofprimitivecells 95
5.7 Self-assemblyprocessesinprebioticorganicmixtures 100
5.8 Emergenceofmembranefunctions 101
5.9 Emergenceofgrowthprocessesinprimitivecells 103
5.10 Environmentalconstraintsonthefirstformsoflife 105
Contents vii
Acknowledgements 106
References 106
PartII LifeonEarth 111
6 Extremophiles:definingtheenvelopeforthesearchforlife
intheuniverse 113
LynnRothschild
6.1 Introduction 113
6.2 Whatisanextremophile? 114
6.3 Categoriesofextremophiles 115
6.4 Environmentalextremes 115
6.5 Howdotheydoit? 123
6.6 Examplesofextremeecosystems 125
6.7 Space:newcategoriesofextremeenvironments 126
6.8 LifeintheSolarSystem? 127
6.9 Conclusions 130
Acknowledgements 131
References 131
7 HyperthermophiliclifeonEarth–andonMars? 135
KarlO.Stetter
7.1 Introduction 135
7.2 Biotopes 136
7.3 Samplingandcultivation 138
7.4 Phylogeneticimplications 139
7.5 Physiologicproperties 141
7.6 ExamplesofrecentHTorganisms 143
References 147
8 Phylogenomics:howfarbackinthepastcanwego? 149
HennerBrinkmann,DenisBaurain,andHervéPhilippe
8.1 Introduction 149
8.2 Theprinciplesofphylogeneticinference 149
8.3 Artefactsaffectingphylogeneticreconstruction 152
8.4 Strengthsandlimitationsofphylogenomics 155
8.5 Theimportanceofsecondarysimplification 160
8.6 Thetreeoflife 164
8.7 Frequentstrongclaimsmadewithweakevidence
intheirfavour 167
viii Contents
8.8 Conclusions 171
Acknowledgements 171
References 172
9 Horizontalgenetransfer,genehistories,andtheroot
ofthetreeoflife 178
OlgaZhaxybayevaandJ.PeterGogarten
9.1 Introduction 178
9.2 Howtoanalysemultigenedata? 179
9.3 Whatdoesthepluralityconsensusrepresent?
Exampleofsmallmarinecyanobacteria 182
9.4 Whereistherootofthe‘treeoflife’? 183
9.5 Useofhigherordercharacters:exampleofATPases 185
9.6 Conclusions 188
Acknowledgements 188
References 188
10 Evolutionaryinnovationversusecologicalincumbency 193
AdolfSeilacher
10.1 TheEdiacaranworld 193
10.2 Preservationalcontext 194
10.3 Vendobiontsasgiantprotozoans 195
10.4 Kimberella asastem-groupmollusc 198
10.5 Wormburrows 202
10.6 Stabilityofecosystems 203
10.7 Theparasiteconnection 204
10.8 Conclusions 207
Acknowledgements 208
References 208
11 Gradualoriginforthemetazoans 210
AlexandraPontefractandJonathonStone
11.1 Introduction 210
11.2 Collagenasatraittyingtogethermetazoans 211
11.3 Thecriticaloxygenconcentrationcriterion 212
11.4 TheBurgessShalefauna:aradiationonrockyground 213
11.5 AccumulatingevidenceaboutsnowballEarth 215
◦
11.6 Northof80 216
11.7 Conclusion 219
Contents ix
Acknowledgements 219
References 219
PartIII LifeintheSolarSystem? 223
12 ThesearchforlifeonMars 225
ChrisP.McKay
12.1 Introduction 225
12.2 MarstodayandtheVikingsearchforlife 227
12.3 Searchforsecondgenesis 229
12.4 DetectingasecondgenesisonMars 235
12.5 Conclusions 238
References 238
13 LifeinthedarkdunespotsofMars:atestablehypothesis 241
EörsSzathmáry,TiborGánti,TamásPócs,AndrásHorváth,Ákos
Kereszturi,SzaniszlóBérczi,andAndrásSik
13.1 Introduction 241
13.2 History 241
13.3 BasicfactsandconsiderationsaboutDDSs 243
13.4 Challengesandanswers 250
13.5 PartialanaloguesonEarth 255
13.6 Discussionandoutlook 257
Acknowledgements 258
References 258
14 Titan:anewastrobiologicalvisionfromthe
Cassini–Huygensdata 263
FrançoisRaulin
14.1 Introduction 263
14.2 AnalogiesbetweenTitanandtheEarth 264
14.3 Acomplexprebiotic-likechemistry 271
14.4 LifeonTitan? 278
14.5 Conclusions 280
Acknowledgements 281
References 282
15 Europa,theoceanmoon:tides,permeableice,andlife 285
RichardGreenberg
15.1 Introduction:lifebeyondthehabitablezone 285
15.2 ThesurfaceofEuropa 286
