Related papers: Life After Earth
Previous studies modelled the origin of life and the emergence of photosynthesis on the early Earth-i.e. the origin of plants-in terms of biological heat engines that worked on thermal cycling caused by suspension in convecting water. In…
Topological defects are common in many everyday systems. In general, they appear if a symmetry is broken at a rapid phase transition. In this article, I explain why it is believed that they should have also been formed in the early universe…
Nature has found one method of organizing living matter, but maybe other options exist -- not yet discovered -- on how to create life. To study the life "as it could be" is the objective of an interdisciplinary field called Artificial Life…
There has been on-going philosophical debate on whether artificial life models, also known as digital organisms, are truly alive. The main difficulty appears to be finding an encompassing and definite definition of life. By examining…
We introduce a new model for large scale evolution and extinction in which species are organized into food chains. The system evolves by two processes: origination/speciation and extinction. In the model, extinction of a given species can…
In biology, the evolution of increasingly cooperative groups has shaped the history of life. Genes collaborate in the control of cells; cells efficiently divide tasks to produce cohesive multicellular individuals; individual members of…
In a previous paper we addressed the question "Does the Rapid Appearance of Life on Earth Suggest that Life is Common in the Universe?" The non-observability of recent biogenesis is a self-selection effect that needs to be considered if…
There is growing evidence that brown dwarfs may be comparable to main-sequence stars in terms of their abundance. In this paper, we explore the prospects for the existence of life on Earth-like planets around brown dwarfs. We consider the…
Genomic complexity can be used as a clock with which the moment in which life originated can be measured. Some authors who have studied this problem have come to the conclusion that it is not possible that terrestrial life originated here…
Many of life's most fascinating phenomena emerge from interactions among many elements--many amino acids determine the structure of a single protein, many genes determine the fate of a cell, many neurons are involved in shaping our thoughts…
An introductory account is given of the understanding of the structure of the universe. At present the most plausible theory of the origin of the universe is that it formed from the explosion of an extremely hot and dense fireball several…
One of the unique features associated with the Earth is that the fraction of its surface covered by land is comparable to that spanned by its oceans and other water bodies. Here, we investigate how extraterrestrial biospheres depend on the…
If an industrial civilization had existed on Earth many millions of years prior to our own era, what traces would it have left and would they be detectable today? We summarize the likely geological fingerprint of the Anthropocene, and…
We study the probabilities of evolution based on random mutations and natural selection. We conclude that evolution to multicellular eukaryots, or even prokaryots, is unlikely to be the result of only random mutations. Complex organisms…
The quest for life in the Universe is often affected by the free use of extrapolations of our phenomenological geocentric knowledge. We point out that the existence of a living organism, and a population of organisms, requires the existence…
The existence of life is one of the most fundamental problems of astrophysics. The intriguing existence of progressively complex and apparently improbable living beings should be a general tendency of life in the Universe. We are looking…
Interpretation of empirical results based on a taxa's lifetime distribution shows apparently conflicting results. Species' lifetime is reported to be exponentially distributed, whereas higher order taxa, such as families or genera, follow a…
The future biosphere on Earth (as with its past) will be made up predominantly of unicellular microorganisms. Unicellular life was probably present for at least 2.5 Gyr before multicellular life appeared and will likely be the only form of…
This note presents a minimal approach to the origin of life, following standard ideas. We pay special attention to the point of view of non-equilibrium statistical mechanics, and in particular to detailed balance. As a consequence we…
Jim Shapiro synthesizes a great many observations about the mechanisms of evolution to reach the remarkable conclusion that large-scale modification, exchange, and rearrangement of the genome are common and should be viewed as fundamental…