scholarly journals The most primitive extant ancestor of organisms and discovery of definitive evolutionary equations

2018 ◽  
Author(s):  
Kenji Sorimachi
Keyword(s):  
Natural Selection ◽  
Regression Line ◽  
Biological Evolution ◽  
Evolutionary Divergence ◽  
Logarithmic Function ◽  
Evolutionary Equations ◽  
Nucleotide Content ◽  
Molecular Features ◽  
Whole Genomes ◽  
The Origin Of Life

AbstractOrganisms are classified into three domains, Prokaryota, Archaea, and Eukaryota, and their evolutionary divergence has been characterized based on morphological and molecular features using rationale based on Darwin’s theory of natural selection. However, universal rules that govern genome evolution have not been identified. Here, a simple, innovative approach has been developed to evaluate biological evolution initiating the origin of life: whole genomes were divided into several fragments, and then differences in normalized nucleotide content between nucleotide pairs were compared. Based on nucleotide content structures, Monosiga brevicollis mitochondria may be the most primitive extant ancestor of the species examined here. The two normalized nucleotide contents are universally expressed by a linear regression line, (X − Y)/(X + Y) = a (X − Y) + b, where X and Y are nucleotide contents and (a) and (b) are constants. The value of (G + C), (G + A), (G + T), (C + A), (C + T) and (A + T) was ~0.5. Plotting (X − Y)/(X + Y) against X/Y showed a logarithmic function (X − Y)/(X + Y) = a ln X/Y + b, where (a) and (b) are constant. Nucleotide content changes are expressed by a definitive equation, (X − Y) ≈ 0.25 ln(X/Y).

The Tempo and mode(S) of Prebiotic Evolution

1997 ◽  
Vol 161 ◽  
pp. 419-429 ◽  
Author(s):  
Antonio Lazcano
Keyword(s):  
Origin Of Life ◽  
Organic Compounds ◽  
Biological Evolution ◽  
Current Evidence ◽  
Early Diversification ◽  
Time Period ◽  
The Galaxy ◽  
History Of ◽  
Widespread Phenomenon ◽  
The Origin Of Life

AbstractDifferent current ideas on the origin of life are critically examined. Comparison of the now fashionable FeS/H2S pyrite-based autotrophic theory of the origin of life with the heterotrophic viewpoint suggest that the later is still the most fertile explanation for the emergence of life. However, the theory of chemical evolution and heterotrophic origins of life requires major updating, which should include the abandonment of the idea that the appearance of life was a slow process involving billions of years. Stability of organic compounds and the genetics of bacteria suggest that the origin and early diversification of life took place in a time period of the order of 10 million years. Current evidence suggest that the abiotic synthesis of organic compounds may be a widespread phenomenon in the Galaxy and may have a deterministic nature. However, the history of the biosphere does not exhibits any obvious trend towards greater complexity or «higher» forms of life. Therefore, the role of contingency in biological evolution should not be understimated in the discussions of the possibilities of life in the Universe.

Randomness and Complexity

2018 ◽  
Author(s):  
Steven E. Vigdor
Keyword(s):  
Quantum Mechanics ◽  
Natural Selection ◽  
Rna World ◽  
Biological Evolution ◽  
Variable Theory ◽  
Cosmological Natural Selection ◽  
Einstein Podolsky Rosen ◽  
World Hypothesis ◽  
Rna World Hypothesis

Chapter 7 describes the fundamental role of randomness in quantum mechanics, in generating the first biomolecules, and in biological evolution. Experiments testing the Einstein–Podolsky–Rosen paradox have demonstrated, via Bell’s inequalities, that no local hidden variable theory can provide a viable alternative to quantum mechanics, with its fundamental randomness built in. Randomness presumably plays an equally important role in the chemical assembly of a wide array of polymer molecules to be sampled for their ability to store genetic information and self-replicate, fueling the sort of abiogenesis assumed in the RNA world hypothesis of life’s beginnings. Evidence for random mutations in biological evolution, microevolution of both bacteria and antibodies and macroevolution of the species, is briefly reviewed. The importance of natural selection in guiding the adaptation of species to changing environments is emphasized. A speculative role of cosmological natural selection for black-hole fecundity in the evolution of universes is discussed.

Comparison of fundamental physical properties of the model cells (protocells) and the living cells reveals the need in protophysiology

2016 ◽  
Vol 16 (1) ◽  
pp. 97-104 ◽  
Author(s):  
V.V. Matveev
Keyword(s):  
Physical Properties ◽  
Origin Of Life ◽  
Sodium Pump ◽  
Molecular Model ◽  
Biological Evolution ◽  
Living Cells ◽  
Real Problem ◽  
The Origin Of Life ◽  
Physical Laws ◽  
Fundamental Physical

AbstractA hypothesis is proposed about potassium ponds being the cradles of life enriches the gamut of ideas about the possible conditions of pre-biological evolution on the primeval Earth, but does not bring us closer to solving the real problem of the origin of life. The gist of the matter lies in the mechanism of making a delimitation between two environments – the intracellular environment and the habitat of protocells. Since the sodium–potassium pump (Na+/K+-ATPase) was discovered, no molecular model has been proposed for a predecessor of the modern sodium pump. This has brought into life the idea of the potassium pond, wherein protocells would not need a sodium pump. However, current notions of the operation of living cells come into conflict with even physical laws when trying to use them to explain the origin and functioning of protocells. Thus, habitual explanations of the physical properties of living cells have become inapplicable to explain the corresponding properties of Sidney Fox's microspheres. Likewise, existing approaches to solving the problem of the origin of life do not see the need for the comparative study of living cells and cell models, assemblies of biological and artificial small molecules and macromolecules under physical conditions conducive to the origin of life. The time has come to conduct comprehensive research into the fundamental physical properties of protocells and create a new discipline – protocell physiology or protophysiology – which should bring us much closer to solving the problem of the origin of life.

scholarly journals Marine Prasinovirus Genomes Show Low Evolutionary Divergence and Acquisition of Protein Metabolism Genes by Horizontal Gene Transfer

2010 ◽  
Vol 84 (24) ◽  
pp. 12555-12563 ◽  
Author(s):  
Hervé Moreau ◽  
Gwenael Piganeau ◽  
Yves Desdevises ◽  
Richard Cooke ◽  
Evelyne Derelle ◽  
...  
Keyword(s):  
Gene Transfer ◽  
Viral Evolution ◽  
Genome Comparison ◽  
Evolutionary Divergence ◽  
Gene Repertoire ◽  
Whole Genomes ◽  
Complete Sequences ◽  
Virus Genomes ◽  
High Degree ◽  
Ostreococcus Lucimarinus

ABSTRACT Although marine picophytoplankton are at the base of the global food chain, accounting for half of the planetary primary production, they are outnumbered 10 to 1 and are largely controlled by hugely diverse populations of viruses. Eukaryotic microalgae form a ubiquitous and particularly dynamic fraction of such plankton, with environmental clone libraries from coastal regions sometimes being dominated by one or more of the three genera Bathycoccus, Micromonas, and Ostreococcus (class Prasinophyceae). The complete sequences of two double-stranded (dsDNA) Bathycoccus, one dsDNA Micromonas, and one new dsDNA Ostreococcus virus genomes are described. Genome comparison of these giant viruses revealed a high degree of conservation, both for orthologous genes and for synteny, except for one 36-kb inversion in the Ostreococcus lucimarinus virus and two very large predicted proteins in Bathycoccus prasinos viruses. These viruses encode a gene repertoire of certain amino acid biosynthesis pathways never previously observed in viruses that are likely to have been acquired from lateral gene transfer from their host or from bacteria. Pairwise comparisons of whole genomes using all coding sequences with homologous counterparts, either between viruses or between their corresponding hosts, revealed that the evolutionary divergences between viruses are lower than those between their hosts, suggesting either multiple recent host transfers or lower viral evolution rates.

scholarly journals The Impact of 'Anthropotechnology' on Human Evolution

2010 ◽  
Vol 14 (2) ◽  
pp. 72-87 ◽  
Author(s):  
Sylvia Blad ◽  
Keyword(s):  
Natural Selection ◽  
Human Evolution ◽  
Common Ancestor ◽  
Biological Evolution ◽  
Genetic Effects ◽  
Evolutionary Path ◽  
Peter Sloterdijk ◽  
The Impact

From the time that they diverged from their common ancestor, chimpanzees and humans have had a very different evolutionary path. It seems obvious that the appearance of culture and technology has increasingly alienated humans from the path of natural selection that has informed chimpanzee evolution. According to philosopher Peter Sloterdijk any type of technology is bound to have genetic effects. But to what extent do genomic comparisons provide evidence for such an impact of ‘anthropotechnology’ on our biological evolution?

Revisiting Hull's Evolutionary Model of Science

2021 ◽  
Vol 13 (2) ◽  
pp. 145-152
Author(s):  
Mohammad Mahdi Hatef ◽  
Keyword(s):  
Natural Selection ◽  
Selection Process ◽  
Biological Evolution ◽  
Evolutionary Model ◽  
Scientific Change ◽  
Evolutionary Models ◽  
Natural Evolution ◽  
The Difference

Evolutionary models for scientific change are generally based on an analogy between scientific changes and biological evolution. Some dissimilarity cases, however, challenge this analogy. An issue discussed in this essay is that despite natural evolution, which is currently considered to be non-globally progressive, science is a phenomenon that we understand as globally progressive. David Hull's solution to this disanalogy is to trace the difference back to their environments, in which processes of natural selection and conceptual selection occur. I will provide two arguments against this solution, showing that Hull's formulation of natural selection prohibits him from removing the environment from the selection process. Then I point to a related tension in his theory, between realism and externalism in science, and give some suggestions to solve these tensions.

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.

Combinatorics of Genotype-Phenotype Maps: An RNA Case Study

2005 ◽  
Author(s):  
Christian M. Reidys
Keyword(s):  
Natural Selection ◽  
Genetic Drift ◽  
Optimization Problem ◽  
Neutral Theory ◽  
Biological Evolution ◽  
Neutral Evolution ◽  
Evolutionary Search ◽  
Random Drift ◽  
Molecular Change ◽  
Biological Phenomena

The fundamental mechanisms of biological evolution have fascinated generations of researchers and remain popular to this day. The formulation of such a theory goes back to Darwin (1859), who in the The Origin of Species presented two fundamental principles: genetic variability caused by mutation, and natural selection. The first principle leads to diversity and the second one to the concept of survival of the fittest, where fitness is an inherited characteristic property of an individual and can basically be identified with its reproduction rate. Wright [530, 531] first recognized the importance of genetic drift in evolution in improving the evolutionary search capacity of the whole population. He viewed genetic drift merely as a process that could improve evolutionary search. About a decade later, Kimura proposed [317] that the majority of changes that are observed in evolution at the molecular level are the results of random drift of genotypes. The neutral theory of Kimura does not deny that selection plays a role, but claims that no appreciable fraction of observable molecular change can be caused by selective forces: mutations are either a disadvantage or, at best, neutral in present day organisms. Only negative selection plays a major role in the neutral evolution, in that deleterious mutants die out due to their lower fitness. Over the last few decades, there has been a shift of emphasis in the study of evolution. Instead of focusing on the differences in the selective value of mutants and on population genetics, interest has moved to evolution through natural selection as an abstract optimization problem. Given the tremendous opportunities that computer science and the physical sciences now have for contributing to the study of biological phenomena, it is fitting to study the evolutionary optimization problem in the present volume. In this chapter, we adopt the following framework: assuming that selection acts exclusively upon isolated phenotypes, we introduce the following compositum of mappings . . . Genotypes→ Phenotypes →Fitness . . . . We will refer to the first map as to the genotype-phenotype map and call the preimage of a given phenotype its neutral network. Clearly, the main ingredients here are the phenotypes and genotypes and their respective organization. In the following we will study various combinatorial properties of phenotypes and genotypes for RNA folding maps.

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