The Origin of Life on Earth and the Design of Alternative Life Forms

2019 ◽  
pp. 239-268
Author(s):  
Jack W. Szostak
Keyword(s):  
Origin Of Life ◽  
Life Forms ◽  
The Origin Of Life ◽  
Life On Earth

scholarly journals The Origin of Life on Earth and the Design of Alternative Life Forms

2017 ◽  
Vol 01 (02) ◽  
pp. 121-131 ◽  
Author(s):  
Jack W. Szostak
Keyword(s):  
Nucleic Acids ◽  
Origin Of Life ◽  
Artificial Life ◽  
Building Blocks ◽  
Life Forms ◽  
Chemical Energy ◽  
Synthetic Chemistry ◽  
Broad Scope ◽  
The Origin Of Life ◽  
Life On Earth

To understand the origin of life on Earth, and to evaluate the potential for life on exoplanets, we must understand the pathways that lead from chemistry to biology. Recent experiments suggest that a chemically rich environment that provides the building blocks of membranes, nucleic acids and peptides, along with sources of chemical energy, could result in the emergence of replicating, evolving cells. The broad scope of synthetic chemistry suggests that it may be possible to design and construct artificial life forms based upon a very different biochemistry than that of existing biology.

scholarly journals The Generalized Definition of Life

2021 ◽  
Author(s):  
vivek kumar
Keyword(s):  
Origin Of Life ◽  
Life Forms ◽  
Living Systems ◽  
Definition Of Life ◽  
The Origin Of Life ◽  
Definition Of ◽  
Life On Earth

In this article, I propose and discuss a new definition of life. This new definition considers reproduction and evolution as major aspects of life. It brings into consideration a variety of other life forms like inorganic life, etc. In this study, I aim to present the possibility of various life forms and some of their properties, which might help understand the origin of life on earth and the existence of life in other parts of the cosmos. This new proposed definition of life is independent of the mode of evolution and general enough to consider all potential life forms. This article uses NASA’s definition of life as a structure to derive this generalized definition of life. Finding and exploring new living systems will definitely be very helpful in understanding the aspects of life. In order to explain some complex life forms, a new concept of addition of living systems is introduced in this article. This study underscores the need for further work to understand the origin and properties of living systems.

scholarly journals Defining the envelope for the search for life in the Universe

2009 ◽  
Vol 5 (H15) ◽  
pp. 697-698
Author(s):  
Lynn J. Rothschild
Keyword(s):  
Origin Of Life ◽  
Life Forms ◽  
Chemical Parameters ◽  
Theoretical Possibility ◽  
Origin And Evolution ◽  
Set Constraints ◽  
The Origin Of Life ◽  
Life On Earth ◽  
Physical And Chemical ◽  
The Universe

AbstractThe search for life in the universe relies on defining the limits for life and finding suitable conditions for its origin and evolution elsewhere. From the biological perspective, a conservative approach uses life on earth to set constraints on the environments in which life can live. Conditions for the origin of life, even on earth, cannot yet be defined with certainty. Thus, we will describe what is known about conditions for the origin of life and limits to life on earth as a template for life elsewhere, with a particular emphasis on such physical and chemical parameters as temperature, pH, salinity, desiccation and radiation. But, other life forms could exist, thus extending the theoretical possibility for life elsewhere. Yet, this potential is not limitless, and so constraints for life in the universe will be suggested.

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.

What is life?

1997 ◽  
Author(s):  
John Maynard Smith ◽  
Eors Szathmary
Keyword(s):  
Natural Selection ◽  
Origin Of Life ◽  
Definition Of Life ◽  
The Sun ◽  
Physical Processes ◽  
Living Things ◽  
Survival And Reproduction ◽  
The Origin Of Life ◽  
Definition Of ◽  
Life On Earth

Imagine that, when the first spacemen step out of their craft onto the surface of one of the moons of Jupiter, they are confronted by an object the size of a horse, rolling towards them on wheels, and bearing on its back a concave disc pointing towards the Sun. They will at once conclude that the object is alive, or has been made by something alive. If all they find is a purple smear on the surface of the rocks, they will have to work harder to decide. This is the phenotypic approach to the definition of life: a thing is alive if it has parts, or ‘organs’, which perform functions. William Paley explained the machine-like nature of life by the existence of a creator: today, we would invoke natural selection. There are, however, dangers in assuming that any entity with the properties of a self-regulating machine is alive, or an artefact. In section 2.2, we tell the story of a self-regulating atomic reactor, the Oklo reactor, which is neither. This story can be taken in one of three ways. First, it shows the dangers of the phenotypic definition of life: not all complex entities are alive. Second, it illustrates how the accidents of history can give rise spontaneously to surprisingly complex machine-like entities. The relevance of this to the origin of life is obvious. In essence, the problem is the following. How could chemical and physical processes give rise, without natural selection, to entities capable of hereditary replication, which would therefore, from then on, evolve by natural selection? The Oklo reactor is an example of what can happen. Finally, section 2.2 can simply be skipped: the events were interesting, but do not resemble in detail those that led to the origin of life on Earth. There is an alternative to the phenotypic definition of life. It is to define as alive any entities that have the properties of multiplication, variation and heredity. The logic behind this definition, first proposed by Muller (1966), is that a population of entities with these properties will evolve by natural selection, and hence can be expected to acquire the complex adaptations for survival and reproduction that are characteristic of living things.

Sign in / Sign up

Export Citation Format

Share Document