Hostname: page-component-78c5997874-dh8gc Total loading time: 0 Render date: 2024-11-09T01:36:39.693Z Has data issue: false hasContentIssue false

Evolutionary exobiology: towards the qualitative assessment of biological potential on exoplanets

Published online by Cambridge University Press:  25 October 2017

David S. Stevenson*
Affiliation:
Carlton le Willows Academy, Wood Lane, Gedling, Nottinghamshire NG4 4AA, UK
Sean Large*
Affiliation:
University of Exeter, College of Engineering, Mathematics and Physical Sciences, North Park Road, Exeter EX4 4QF, UK
*
Authors for correspondence: David S. Stevenson and Sean Large, E-mail: [email protected], [email protected]
Authors for correspondence: David S. Stevenson and Sean Large, E-mail: [email protected], [email protected]

Abstract

A planet may be defined as habitable if it has an atmosphere and is warm enough to support the existence of liquid water on its surface. Such a world has the basic set of conditions that allow it to develop life similar to ours, which is carbon-based and has water as its universal solvent. While this definition is suitably vague to allow a fairly broad range of possibilities, it does not address the question as to whether any life that does form will become either complex or intelligent. In this paper, we seek to synthesize a qualitative definition of which subset of these ‘habitable worlds’ might develop more complex and interesting life forms. We identify two key principles in determining the capacity of life to breach certain transitions on route to developing intelligence. The first is the number of potential niches a planet provides. Secondly, the complexity of life will reflect the information density of its environment, which in turn can be approximated by the number of available niches. We seek to use these criteria to begin the process of placing the evolution of terrestrial life in a mathematical framework based on environmental information content. This is currently testable on Earth and will have clear application to the worlds that we are only beginning to discover. Our model links the development of complex life to the physical properties of the planet, something which is currently lacking in all evolutionary theory.

Type
Research Article
Copyright
Copyright © Cambridge University Press 2017 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Alibert, Y and Benz, W (2017) Formation and composition of planets around very low mass stars. Astron. Astrophys., 598, 14, doi: 10.1051/0004-6361/201629671Google Scholar
Allen, JF and Vermaas, WFJ (2010) Evolution of photosynthesis. In Encyclopedia of Life Sciences (ELS). John Wiley & Sons, Ltd., Chichester. doi: 10.1002/9780470015902.a0002034.pub2.Google Scholar
Anglada-Escudé, G et al. (2016) A terrestrial planet candidate in a temperate orbit around Proxima Centauri. Nature 536, 437440. doi: 10.1038/nature19106.Google Scholar
Brin, D (1983) The ‘great silence’: the controversy concerning extraterrestrial intelligent life. Q. J. R. Astron. Soc. 24, 283309.Google Scholar
Calcott, B and Sterelny, K (2011) The Major Transitions in Evolution Revisited. Massachusetts Institute of Technology, Cambridge, Massachusetts, ISBN 978-0-262-01524-0.Google Scholar
Carter, B (1993) The anthropic selection principle and the ultra-Darwinian synthesis. In The Anthropic Principle, ed. Bertola, F and Curi, U, pp. 3363. Cambridge University Press, Cambridge.Google Scholar
Chen, X et al. (2015) Rise to modern levels of ocean oxygenation coincided with the Cambrian radiation of animals. Nat. Commun. 6(7142), 17. DOI: 10.1038/ncomms8142.Google Scholar
de Wit, J et al. (2016) A combined transmission spectrum of the Earth-sized exoplanets TRAPPIST-1 b and c. Nature 533(7602), 221224. Preprint available at: https://arxiv.org/pdf/1606.01103v1.pdf.Google Scholar
Dismukes, GC, Klimov, VV, Baranov, SV, Kozlov, YN, DasGupta, J and Tyryshkin, A (2001) The origin of atmospheric oxygen on earth: the innovation of oxygenic photosynthesis. Proc. Natl Acad. Sci. USA 98(5), 21702175.Google Scholar
Fox, D (2016) What sparked the Cambrian explosion? Nature 530, 268270.Google Scholar
Hanson, R (1998) Must Early Life Be Easy? The Rhythm of Major Evolutionary Transitions. Available at: http://mason.gmu.edu/~rhanson/hardstep.pdf.Google Scholar
Heath, MJ, Doyle, LR, Joshi, MM and Haberle, RM (1999) Habitability of planets around red dwarf stars. Origins Life Evol. Biosph. 29, 405424.Google Scholar
Hedges, SB, Blair, JE, Venturi, ML and Shoe, JL (2004) A molecular timescale of eukaryote evolution and the rise of complex multicellular life. BMC Evol. Biol. 4, 19. Available at: http://www.biomedcentral.com/1471-2148/4/2.Google Scholar
Hong, X and Xue-Feng, B (2008) Decomposition of hydrogen sulfide to produce hydrogen under ultraviolet light. Imag. Sci. Photochem. 26(2), 131137. doi: 10.7517/j.issn.1674-0475.2008.02.131.Google Scholar
Koonin, EV (2010) The origin and early evolution of eukaryotes in the light of phylogenomics. Genome Biol. 11, 209. Available at: http://genomebiology.biomedcentral.com/articles/10.1186/gb-2010-11-5-209.Google Scholar
Lenton, TM, Boyle, RA, Poulton, SW, Shields-Zhou, GA and Butterfield, NJ (2014) Co-evolution of eukaryotes and ocean oxygenation in the neoproterozoic era. Nat. Geosci. 7(4), 257265. ISSN .Google Scholar
Loeb, A, Batista, RA and Sloan, D (2016) Relative Likelihood for Life as a Function of Cosmic Time. Available at: http://arxiv.org/pdf/1606.08448v2.pdf.Google Scholar
Mahaffy, PR et al. (2013) Abundance and isotopic composition of gases in the Martian Atmosphere from the Curiosity Rover. Science 341, 263266.Google Scholar
Meert, JG (2012) What's in a name? The Columbia (Paleopangaea/Nuna) supercontinent. Gondwana Res. 21, 987993. doi:10.1016/j.gr.2011.12.002.Google Scholar
Meert, JG and Torsvik, TH (2003) The making and unmaking of a supercontinent: Rodinia revisited. Tectonophysics 375(2003), 261288. doi: 10.1016/S0040-1951(03)00342-. Available at: http://wayback.archive.org/web/20110723122559/http://www.geodynamics.no/guest/RodiniaRevisitedMeert_Torevik.pdf.Google Scholar
Mitchell, RN, Kilian, TM and Evans, DAD (2012) Supercontinent cycles and the calculation of absolute palaeolongitude in deep time. Nature 482, 208211. doi: 10.1038/nature10800Assembly.Google Scholar
Morris, SC (2015) The Runes of Runes of Evolution, The How the Universe Became Self-Aware. West Conshohocken, Pennsylvania: Templeton Press, ISBN 13: 978-1-59947-464-9.Google Scholar
Peters, SE and Gaines, RR (2012) Formation of the ‘Great Unconformity’ as a trigger for the Cambrian explosion. Nature 484, 363366. doi: 10.1038/nature10969.Google Scholar
Price, TD et al. (2014) Niche filling slows the diversification of Himalayan songbirds. Nature 509, 222225. doi: 10.1038/nature13272.Google Scholar
Rabosky, DL and Matute, DR (2013) Macroevolutionary speciation rates are decoupled from the evolution of intrinsic reproductive isolation in Drosophila and birds. Proc. Natl Acad. Sci. USA 110(38), 1535415359. Available at: http://www.pnas.org/cgi/doi/10.1073/pnas.1305529110.Google Scholar
Rosing, MT, Bird, DK, Sleep, NH and Bjerrum, CJ (2010) No climate paradox under the faint early Sun. Nature 464, 744749.Google Scholar
Schirrmeistera, BE, de Vosb, JM, Antonellic, A and Bagheria, HC (2013) Evolution of multicellularity coincided with increased diversification of cyanobacteria and the Great Oxidation Event. Proc. Natl Acad. Sci. USA 110(5), 17911796.Google Scholar
Schopf, JW (1995) The oldest fossils and what they mean. In Major Events in the History of Life, ed. Schopf, JW., pp. 2963. Jones and Bartlett Publishers, Boston.Google Scholar
Shannon, CE (1948a) A mathematical theory of communication. Bell Syst. Tech. J. 27(3), 379423. doi: 10.1002/j.1538-7305.1948.tb01338.x. Available at: http://worrydream.com/refs/Shannon%20-%20A%20Mathematical%20Theory%20of%20Communication.pdf.Google Scholar
Shannon, CE (1948b) A mathematical theory of communication. Bell Syst. Tech. J. 27(4): 623666. doi: 10.1002/j.1538-7305.1948.tb00917.x.Google Scholar
Som, SM, Catling, DC, Harnmeijer, JP, Polivka, PM and Buick, R (2012) Air density 2.7 billion years ago limited to less than twice modern levels by fossil raindrop imprints. Nature 484, 359362.Google Scholar
Som, SM, Buick, R, Hagadorn, JW, Blake, TS, Perreault, JM, Harnmeijer, JP and Catling, DC (2016) Earth's air pressure 2.7 billion years ago constrained to less than half of modern levels. Nat. Geosci. 9, 448451. doi: 10.1038/ngeo2713.Google Scholar
Spiegel, DS and Turner, EL (2011) Life might be rare despite its early emergence on Earth: a Bayesian analysis of the probability of abiogenesis. Proc. Natl Acad. Sci. USA. doi: 10.1073/pnas.0709640104. Available at: http://www.arXiv.1107.3835v1.Google Scholar
Stevenson, DS (2017) The Nature of Life and Its Potential to Survive. Springer, New York. ISBN 978-3-319-52910-3, doi: 10.1007/978-3-319-52911-0.Google Scholar
Supercontinents: a retrospective essay. (2014) Available on Researchgate at: https://www.researchgate.net/publication/235834618_The_Supercontinent_Cycle_A_Retrospective_Essay, doi: 10.1016/j.gr.2012.12.026.Google Scholar
Szathmary, E and Smith, JM (1995) The major transitions in evolution. Nature 374, 227232.Google Scholar
Vance, S, Bouffard, M, Choukroun, M and Sotin, C (2014) Ganymede's internal structure including thermodynamics of magnesium sulfate oceans in contact with ice. Planet. Space Sci. 96, 6270.Google Scholar
Watson, AJ (2008) Implications of an anthropic model of evolution for emergence of complex life and intelligence. Astrobiology 8(1), 175185. doi: 10.1089/ast.2006.0115.Google Scholar
Webster, CR et al. (2013) Isotope ratios of H, C, and O in CO2 and H2O of the Martian atmosphere. Science 341(6143), 260263.Google Scholar
West, J, Bianconi, G, Severini, S and Teschendorff, AE (2012) On Dynamical Network Entropy in Cancer. Available at: https://arxiv.org/pdf/1202.3015v2.pdf.Google Scholar
Wheatley, PJ, Louden, T, Bourrier, V, Ehrenreich, D and Gillon, M (2017) Strong XUV irradiation of the Earth-sized exoplanets orbiting the ultracool dwarf TRAPPIST-1. Monthly Notices of the Royal Astronomical Society: Letters 465(1), L74L78.Google Scholar
Yockey, HP (2005) Information Theory, Evolution, and the Origin of Life. Huberr P. Yockey. Cambridge University Press, Cambridge. ISBN 0·521·80293-8.Google Scholar
Zhao, G, Sun, M, Wilde, SA and Li, S (2003) Accretion and breakup of the paleo-mesoproterozoic Columbia supercontinent: records in the North China Craton. Gondwana Res. 6(3), 417434. doi: 10.1016/S1342-937X(05)70996-5; ISSN: .Google Scholar