Workshop “What is Life? An Extraterrestrial Perspective”

Paris-France, March 22, 2017


The Origin of Life on Earth

Frances Westall The premise of this talk is that, apart from liquid water and carbon molecules, specific environmental conditions were essential for the origin of life. These include volcanic rocks rich in iron and magnesium, more common on the early Earth than the planet today, bathed by warm to hot hydrothermal fluids. The rocks provided reactive substrates producing energy to fuel reactions creating the prebiotic building bricks of life. They also promoted concentration of organic molecules and contributed to their conformation and stabilisation. Where did these reactions take place? Groups working in the field of the origin of life often require quite specific environmental conditions for reactions to take place or to stabilise certain key molecules, conditions that, in fact, are often not compatible with what we know about the early Earth. Rocks dating back to the early history of the Earth paint a rather infernal picture of a planet that was totally different our world today: early Earth was characterised by warm to hot water, small emerged volcanic islands, an atmosphere without oxygen, UV-irradiated surfaces, it was highly volcanically and hydrothermally active, and subject to frequent meteorite impacts. But it is in these extreme conditions that the prebiotic building bricks of life formed and assembled, in protected pores and cracks in rocks, sediments and hydrothermal vents, to create the first protocells. Unfortunately, evidence of these processes is lacking in the geological rock record – the first billion years of Earth’s history has been erased by impact and tectonic recycling of the early crust. Could we find traces of the origin of life and its earliest evolution on Mars where old crust still exists? Hopefully future missions to search for traces of potential life on Mars and to bring rock samples from Mars to Earth for study in a terrestrial laboratory will be able to fill in the gap missing in life’s history on Earth.

Frances Westall is a geologist now working in the very broad discipline of astrobiology, the study of the origins of life and its destiny in the Universe. After a PhD in marine geology at the University of Cape Town in South Africa, she worked in various research institutes around the world: the Alfred Wegener Institute for Polar and Marine Research in Bremehaven in Germany, the University of Nantes in France, the University of Bologna in Italy, the Johnson Space Center and Lunar and Planetary Institute in Houston, USA and, for the last 15 years, she is Director of Research at the CNRS-Orléans in France where she heads the astrobiology group. Her research interests and activities cover study of the earliest traces of life on Earth and the geological environment in which they lived, the artificial fossilisation of bacteria, the search for life on Mars, especially with the ESA/Russian ExoMars 2020 mission, and prebiotic chemistry and the origin of life. She is President of the European Astrobiology Network.

Origins of African Apes and Humans

Brigitte Senut African apes and humans belong to the super-family Hominoidea and share a large part of their evolutionary history which is strongly linked to geographical and environmental changes. Hominoids are known in Africa since the Late Oligocene (25-26 Ma) (for the moment, only in Kenya and Tanzania) and became more Pan-African in the early Miocene (22.5-17.8 Ma). In the Middle Miocene, they dispersed northwards towards Eurasia where they diversified under tropical conditions. In the Upper Miocene, Eurasia became more temperate and the hominoids went extinct there, except in South-East Asia which remained under the tropics and where today the gibbons and the orangutans survive. However, during the Middle and Late Miocene, apes did not disappear from Africa and despite the fact that some scenarios propose that the ancestors of the African apes and humans originated in Eurasia and moved back to Africa (“Back to Africa” hypothesis), a lot of information is available concerning the existence of possible ancestors of gorillas, chimpanzees and humans in the Late Miocene strata of Africa. The fossil material of Late Miocene hominoids of Africa is not as complete as that from Europe, but it is widely dispersed over the continent. However, does this mean that our origins were in Africa, as was suggested by Darwin in the 19th Century? There has been a tendency among scholars to identify a precise cradle of modern African apes and humans as expressed, for example, in the “East Side Story” scenario. However it is probably unrealistic to be so precise because the geographic distribution of species and their paleoenvironments changed over time. During the Miocene, hominoids inhabited tropical areas in both Africa and Europe due to the ease of dispersal between the two areas. There was no permanently uncrossable geographical or ecological barrier between Africa and Eurasia throughout the Miocene and the distribution of the hominoids during the epoch probably reflects shifts in the boundaries between biogeographic realms, making it unlikely that they were ever restricted to a single continent, as in the Back to Africa scenario.

Brigitte Senut is Professor at the Muséum National d’Histoire Naturelle, and was trained (geology and paleontology) at the University Pierre & Marie Curie. She defended a PhD (1978) and a DSc (1987) related to locomotion and systematics in early hominids and fossil apes. She leads or co-leads several expeditions in Africa since 1986 in order to understand the evolution of hominoids and the divergence between the African apes and humans in a geological and paleoenvironmental frame. She was involved in many discoveries of fossil apes and hominids, among them: Otavipithecus (Namibia), Ugandapithecus (Uganda), Orrorin (Kenya), and first modern looking apes (Kenya, Niger). Her research also concerns the evolution of hominoid locomotor patterns and the origins of hominid bipedalism. She also does research on the Namib Desert and the Neogene desertification of Africa and is involved in the study of several mammalian groups (elephant-shrews and springhares) from the Eocene and Miocene of the area. She is teaching courses on hominoid evolution and environment to postgraduate students and is interested in the role of natural sciences in sustainable development. She is recipient of several prices and awards and has published more than 300 scientific papers and over 100 popular articles.

Evolutionary trends in life and intelligence

Jean-Pierre Rospars Is the development of intelligence (in)evitable? The answer to this question has widely varied among biologists, with a few of them maintaining that life is ‘an obligatory manifestation of matter’ whereas many other leading evolutionary biologists argue that the probability of intelligent life evolving elsewhere in the universe is vanishingly small. The former but not the latter believe that, because of the universality of the laws of physics and chemistry, evolutionary trends to higher forms of organization, especially toward forms supporting the apparition of intelligent beings, may exist both on Earth and elsewhere. We review some of the facts, interpretations and arguments that lie behind such dissenting views about the existence and nature of evolutionary trends in relation with the apparition of ‘intelligence’. Measurements of quantitative variables that describe important features of the evolution of living organisms – their hierarchical organization, size and biodiversity – and of brains – their overall size, the number and size of their components – provide reliable evidence of the reality and generality of evolutionary trends in terrestrial organisms. Then, we examine trends in cognitive abilities which raise several questions like how to measure intelligence, how is intelligence related to brain size, and does intelligence facilitate survival? Qualitative and quantitative properties of trends are inferred and frequent misinterpretations, including an excessive stress traditionally on ‘progress’ and more recently on mere ‘complexity’, that prevent the objective assessment of trends, are considered. Finally, several arguments against the repeatability of evolution to intelligence are discussed.

Jean-Pierre Rospars received degrees in engineering from École Nationale Supérieure Agronomique, Rennes, France in 1972 and in biophysics from University Pierre and Marie Curie in 1973. He earned his Doctorat d’État ès Sciences in neurobiology from Université Paris-Sud (Orsay) in 1985. Since 1974, he has belonged to the Institut National de la Recherche Agronomique, where he worked in various departments (Zoology, Neurobiology, Biometry and Statistics). He is currently emeritus research director at the Paris Institute of Ecology and Environmental Sciences. He has published more than 100 papers in peer-reviewed journals and books on the structure and function of olfactory systems. His main contributions, combining experiments and models, concern the organization and development of the antennal lobes in the insect brain, the biochemical and electrical transduction mechanisms in receptor neurons, and the integration of olfactory information in primary brain centers of insects and vertebrates. In 1995, he launched the biennial Neural Coding workshops. His work in neuroscience is part of a wider interest in the evolution of life and consciousness in the universe. In this area, he has recently co-edited a special issue of the Int. J. Astrobiol. on Drake Equation and co-authored studies deriving fundamental biological properties from physics.

Evolution and the Psychology of Extraterrestrials

Jerome H. Barkow Extraterrestrial psychologies are often portrayed in science fiction as an exaggeration or parody of one aspect of human psychology. Think of Star Trek’s Ferengi, grotesque capitalists whose major motivation is usually unmitigated greed; or of that universe’s Klingons, originally a harsh, brutal, ever-angry warrior species. ETIs with such simple psychologies make little evolutionary sense because their psychology would not be what John Maynard-Smith (1972) termed an “evolutionarily stable strategy” (ESS). They could not evolve. But even expert opinion about extraterrestrial psychology is not above reproach. For example, the idea that because extraterrestrial species are likely to be older than we are they therefore must be more intelligent than we does not necessarily follow: it is also possible that ancient extraterrestrials are stupid. Any species we can communicate with must have a high technology. The latter does not require advanced intelligence. Technology is the product of accumulated knowledge, error-checked, acquired by others, added to and then error-checked again. Advanced technology means that very bright individuals have been recruited to learn and build on knowledge developed in the past, a process that requires culture (accumulation and social transmission of information) and a particular social structure. The average intelligence of the population does not have to be high, but exceptional individuals must be recruited to acquire and add to advancing technological knowledge, and unlike some other types of cultural knowledge it must be empirically fact-checked. Given this kind of culture and social organization enduring over very long time periods, even a low IQ species can produce high technology.

Jerome H. Barkow received a BA in Psychology from Brooklyn College in 1964 and a doctorate in Human Development from the University of Chicago in 1970. He is an emeritus professor of social anthropology at Dalhousie University, Canada and an honorary professor at the Institute of Cognition and Culture, Queen’s University Belfast. Barkow is identified professionally as an anthropologist but his work is interdisciplinary/multidisciplinary and has ranged from analyzing the impact of Islam on Hausa women in West Africa; to how the Bugis of Indonesia could have a sophisticated knowledge of cuisine but scant effective knowledge of child nutrition; to how the Migili gerontocracy of Nigeria’s Middle Belt came to crash. He is known as an editor (with Leda Cosmides and John Tooby) of the volume that helped launch the field of evolutionary psychology, The Adapted Mind; as the author of Darwin, Sex, and Status; and as the editor of a failed attempt to convince mainstream social-cultural anthropology and sociology that evolutionary biology is the infrastructure of their field, Missing the Revolution: Darwinism for Social Scientists. He is currently co-editing (along with Lance Workman and Will Reader) the Cambridge Handbook of Evolutionary Perspectives on Human Behavior. A recurrent annoyed reaction to many impossible science fiction depictions of extraterrestrial intelligences has now led to a strong interest in applying evolutionary psychology and anthropology to astrobiology.

Is our living world only one of many possible alternatives?

Virginie Courtier-Orgogozo Should the tape of life be replayed, would it produce similar living beings? A classical answer has long been “no”, but accumulating data is now challenging this view. Evolution of living beings has involved numerous reiterations at various levels. A survey of the alleles described in the literature that cause phenotypic differences among animals, plants, and yeasts indicates that similar phenotypes have evolved in distinct taxa through independent mutations in the same genes. Does it mean that the range of possibilities for evolution is limited? Does it mean that the tape of life would play the same if rerun? What kinds of living organisms should we expect on other planets if they harbor life?

Virginie Courtier-Orgogozo is a biology researcher at the Institut Jacques Monod in Paris. Her team studies the mutations responsible for differences between species in order to better understand our evolution, past and future. She received the CNRS Bronze Medal and was elected “Young Woman Scientist” of year 2014 in France.

What is life, an informational perspective?

Pierre-Henri Gouyon From a common point of view among evolutionary geneticists, living individuals are artefacts invented by genes to be reproduced. Indeed, the evolutionary process of selection has progressively produced sets of genetic information coding the production of organisms reproducing them as efficiently as possible in the environment as it is. Any living being, on Earth or elsewhere, can just be defined as a finalized structure devoted to reproduce a coded information, a genetic information. Does this mean that any living being is totally determined by its genes? Any living being results from the reading and interpretation of its genetic information by a biological and cellular structure. The decoding of this information of this information is realized by a complex biochemical machinery starting from molecules which interact with DNA, read it, copy it, translate it into proteins etc., hormones and the whole functioning of the organism. This reading system “interprets” the genome (like a musician interpreting a part). Of course, itself contains information. This information is called epigenetic; it became an intense research field during the last years. Genetic and epigenetic information co-construct the organism. This co-construction results in a complexity which constitutes the center of active research but also of numerous misinterpretations, particularly because it interacts with strong ideological choices which deeply influence our ideas. Could we try to untangle this network? What can we predict about the living beings which we could meet in the Universe?

Pierre-Henri Gouyon is a biologist specialized in sciences of evolution, genetics, botany and ecology. He obtain PhD in Ecology at Montpellier University in 1976 and in Agronomy in Paris in 1978, then a “Doctorat d'État ès Sciences” at Montpellier University in 1982 and a Masters (DEA) in Philosophy at Montpellier University in 1984. Pierre-Henri Gouyon is presently Professor at the Muséum National d’Histoire Naturelle in Paris as well as Professor at the AgroParisTech (since 1988), at the Ecole Normale Supérieure and at Sciences Po (Institut d’Études Politique) in Paris where he teaches the course of Biodiversity. He belongs to the Institut de Systématique, Evolution, Biodiversité which is a joint lab between the MNHN and the CNRS. His research is devoted to the mechanistic study of evolution, from genetics to ecology. He has published numerous (more than 120) publications in the greatest international