scholarly journals The Multiple Paths to Multiple Life

2021 ◽  
Author(s):  
Christopher P. Kempes ◽  
David C. Krakauer
Keyword(s):  
Adaptive Systems ◽  
Origins Of Life ◽  
Function Optimization ◽  
Data Set ◽  
Multiple Origins ◽  
Multiple Paths ◽  
Nested Hierarchy ◽  
The Origin Of Life ◽  
Life On Earth ◽  
Material Form

AbstractWe argue for multiple forms of life realized through multiple different historical pathways. From this perspective, there have been multiple origins of life on Earth—life is not a universal homology. By broadening the class of originations, we significantly expand the data set for searching for life. Through a computational analogy, the origin of life describes both the origin of hardware (physical substrate) and software (evolved function). Like all information-processing systems, adaptive systems possess a nested hierarchy of levels, a level of function optimization (e.g., fitness maximization), a level of constraints (e.g., energy requirements), and a level of materials (e.g., DNA or RNA genome and cells). The functions essential to life are realized by different substrates with different efficiencies. The functional level allows us to identify multiple origins of life by searching for key principles of optimization in different material form, including the prebiotic origin of proto-cells, the emergence of culture, economic, and legal institutions, and the reproduction of software agents.

Pyrite and the Origins of Life

Pyrite ◽  
2015 ◽  
Author(s):  
David Rickard
Keyword(s):  
Origin Of Life ◽  
Early Life ◽  
Life Forms ◽  
Origins Of Life ◽  
Sources Of Information ◽  
Ancient India ◽  
Pyrite Formation ◽  
The Origin Of Life ◽  
Life On Earth ◽  
The Relationship

If you have been reading this book since the beginning, you will not be surprised by now to find that you have come across a chapter documenting the involvement of pyrite in the origin of life. This is because you will have read in this book how pyrite has been at the root of many fundamental discoveries about the nature of our world. So you do not suffer more than eyebrow-raising surprise and maybe a gentle throat-clearing in learning that pyrite is contributing to our current understanding of the origins of life. By contrast, if you have dived in at Chapter 9 you probably look at the title of this chapter with disbelief. After all, what could be the connection between a common glitzy mineral and the origin of life? The more diligent reader will have already learned that pyrite formation is intimately associated with biology because most of it is produced by bacteria that extract their oxygen from sulfate and produce hydrogen sulfide. This relationship is so overweening today that pyrite formation controls many fundamental aspects of the Earth’s environment. So what happens if we extend this line of inquiry back to the beginnings of geologic time? We have already seen that the characteristics of ancient pyrite are one of the main sources of information about the nature of the early Earth. The consequence of this is that we know quite a bit about the relationship between pyrite and early life on Earth. In this chapter, we further explore this and review the laboratory work that implicates pyrite itself in the original syntheses of the self-replicating biomolecules that assembled to produce Earth’s first life forms. The thesis that life developed from nonbiological chemistry is a very old idea stretching back through Anaximander in 6th-century BCE Greece to the Vedic writings of ancient India around 1500 BCE and is often called abiogenesis.

scholarly journals ‘Whole Organism’, Systems Biology, and Top-Down Criteria for Evaluating Scenarios for the Origin of Life

Life ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 690
Author(s):  
Clifford F. Brunk ◽  
Charles R. Marshall
Keyword(s):  
Origin Of Life ◽  
Top Down ◽  
Chemical Systems ◽  
Biochemical Pathways ◽  
The Origin Of Life ◽  
Energy And Material Flows ◽  
Complex Scenario ◽  
Life On Earth ◽  
Physical Laws ◽  
Equilibrium Chemical

While most advances in the study of the origin of life on Earth (OoLoE) are piecemeal, tested against the laws of chemistry and physics, ultimately the goal is to develop an overall scenario for life’s origin(s). However, the dimensionality of non-equilibrium chemical systems, from the range of possible boundary conditions and chemical interactions, renders the application of chemical and physical laws difficult. Here we outline a set of simple criteria for evaluating OoLoE scenarios. These include the need for containment, steady energy and material flows, and structured spatial heterogeneity from the outset. The Principle of Continuity, the fact that all life today was derived from first life, suggests favoring scenarios with fewer non-analog (not seen in life today) to analog (seen in life today) transitions in the inferred first biochemical pathways. Top-down data also indicate that a complex metabolism predated ribozymes and enzymes, and that full cellular autonomy and motility occurred post-LUCA. Using these criteria, we find the alkaline hydrothermal vent microchamber complex scenario with a late evolving exploitation of the natural occurring pH (or Na+ gradient) by ATP synthase the most compelling. However, there are as yet so many unknowns, we also advocate for the continued development of as many plausible scenarios as possible.

Complex Autocatalysis in Simple Chemistries

2016 ◽  
Vol 22 (2) ◽  
pp. 138-152 ◽  
Author(s):  
Nathaniel Virgo ◽  
Takashi Ikegami ◽  
Simon McGregor
Keyword(s):  
Network Structure ◽  
Exponential Growth ◽  
Origins Of Life ◽  
Higher Order ◽  
Nonlinear Phenomena ◽  
Direct Reaction ◽  
Form Complex ◽  
First Order ◽  
Life On Earth ◽  
Catalytic Effects

Life on Earth must originally have arisen from abiotic chemistry. Since the details of this chemistry are unknown, we wish to understand, in general, which types of chemistry can lead to complex, lifelike behavior. Here we show that even very simple chemistries in the thermodynamically reversible regime can self-organize to form complex autocatalytic cycles, with the catalytic effects emerging from the network structure. We demonstrate this with a very simple but thermodynamically reasonable artificial chemistry model. By suppressing the direct reaction from reactants to products, we obtain the simplest kind of autocatalytic cycle, resulting in exponential growth. When these simple first-order cycles are prevented from forming, the system achieves superexponential growth through more complex, higher-order autocatalytic cycles. This leads to nonlinear phenomena such as oscillations and bistability, the latter of which is of particular interest regarding the origins of life.

scholarly journals Petrological implications for the production of methane and hydrogen in hyperalkaline springs from the Othrys ophiolite, Greece.

2013 ◽  
Vol 47 (1) ◽  
pp. 449
Author(s):  
B. Tsikouras ◽  
G. Etiope ◽  
E. Ifandi ◽  
S. Kordella ◽  
G. Papatheodorou ◽  
...  
Keyword(s):  
Low Temperature ◽  
Co2 Hydrogenation ◽  
Ultramafic Rocks ◽  
Mafic Rocks ◽  
Silica Activity ◽  
High Silica ◽  
Greenhouse Gas Budget ◽  
The Origin Of Life ◽  
Life On Earth ◽  
Shed Light

Altered mafic and ultramafic rocks were studied in correspondence with hyperalkaline, CH4-bearing and very low-hydrogen spring waters in the Othrys ophiolite, whose chemical features are typical of present day serpentinisation. The H2 paucity is interpreted as the result of the incorporation of high-silica, aqueous fluids, probably derived from mafic rocks. The vein assemblage of serpentine + magnetite is related to circulation of low-silica fluids whereas serpentine + talc, tremolite after garnet and Fe-rich serpentine in the interior of serpentine veins reflect a late circulation of low-temperature (likely below 120 °C), high silica activity fluids. The highsilica conditions might have limited or interrupted the production of H2, which was subsequently consumed by CO2 hydrogenation to produce CH4. The lack of H2 could also be due to peridotite alteration by CO2-rich fluids. This would imply that the Othrys peridotites, among similar methane-bearing peridotites, may be considered as terrestrial analogues of Martian ultramafic rocks, which are thought to contribute to methane emission in the atmosphere of Mars. Understanding the mechanism of methane abiotic production will likely shed light to the details of some crucial aspects as the greenhouse-gas budget, the production of hydrocarbons and the origin of life on Earth.

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