rekordy: Rare Earth hypothesis

Evidence: 100 • authority: 72

In planetary astronomy and astrobiology, the Rare Earth hypothesis argues that the origin of life and the evolution of biological complexity, such as sexually reproducing, multicellular organisms on Earth, and subsequently human intelligence, required an improbable combination of astrophysical and geological events and circumstances. According to the hypothesis, complex extraterrestrial life is an improbable phenomenon and likely to be rare throughout the universe as a whole. The term "Rare Earth" originates from Rare Earth: Why Complex Life Is Uncommon in the Universe (2000), a book by Peter Ward, a geologist and paleontologist, and Donald E. Brownlee, an astronomer and astrobiologist, bot…

Evidence: 64 • authority: 92

Functional abiotic metabolite assembly hypothesis for the early events in the origin of life.. The RNA world hypothesis provides a compelling framework for the emergence of life, yet a fundamental gap remains between simple abiotic molecules and complex functional RNA polymers. Here, we propose the Functional Abiotic Metabolite Assembly hypothesis, in which simple prebiotically abundant molecules, particularly amino acids and nucleobases, preceded peptides and RNA as self-organizing functional entities. Unlike peptides, which are rarely detected in abiotic contexts, metabolite-like molecules are readily found in meteorites and early Earth simulations and can self-assemble into ordered, amyl…

Evidence: 57 • authority: 92

The hard steps model and whole Earth-system transitions.. The hard steps model is a 'toy' mathematical representation of evolution towards complex life on Earth or Earth-like planets. It assumes that, at the longest time scale, the rate of evolution towards increased complexity is governed by unlikely transitions that happen randomly and rarely. Applied to Earth, the model suggests a small number of such transitions in the pathway to 'intelligent observers'-humans. The transitions are usually envisaged as occurring instantaneously, but this ignores the reality that on Earth, the evolution of life and the planetary environment have been inextricably linked. The critical steps should be seen…

Evidence: 48 • authority: 88

The Origin of Life on Earth, the Panspermia Hypothesis and Cosmological DNA Synthesis. The process of the rapid origin of life on Earth is analyzed, taking into account the evolution of our Sun (the beginning of thermonuclear reactions). Given the knowledge about DNA, viruses and the structure of bacteria, it is concluded that the origin of life on Earth was initiated from the outside. Further, using space chemistry, it is shown that spontaneous assembly of DNA/RNA molecules can occur on particles of interstellar and intergalactic dust. Therefore, when favorable conditions are created on the planet, the emergence of life begins rapidly, since the initiators of life are already available fro…

Evidence: 48 • authority: 92

Can the Timing of the Origin of Life Be Inferred from Trends in the Growth of Organismal Complexity?. The origin of life embodies two fundamental questions: how and when did life begin? It is commonly conjectured that life began on Earth around 4 billion years ago. This requires that the complex organization of RNA, DNA, triplet codon, protein, and lipid membrane (RDTPM) architecture was easy to establish between the time the Earth cooled enough for liquid water and the time when early microorganisms appeared. These bracketing events create a narrow window of time to construct a completely operational self-replicating organic system of very high complexity. Another conjecture is that life d…

Evidence: 48 • authority: 72

The Snowball Earth is a geohistorical hypothesis proposing that during one or more of Earth's icehouse climates, the planet's surface was nearly entirely frozen, with little or no liquid water exposed. This global glaciation hypothesis is most commonly associated with the Cryogenian Period, which included two major glacial episodes: the Sturtian (c. 717–660 Ma) and Marinoan (c. 650–635 Ma). Proponents of the hypothesis argue that it best explains sedimentary deposits that are generally believed to be of glacial origin at tropical palaeolatitudes and other enigmatic features in the geological record. Opponents of the hypothesis contest the geological evidence for global glaciation and the ge…

Evidence: 48 • authority: 72

The natural history of Earth concerns the development of planet Earth from its formation to the present day. Nearly all branches of natural science have contributed to the understanding of the main events of Earth's past, characterized by constant geological change and biological evolution. The geological time scale (GTS), as defined by international convention, depicts the large spans of time from the beginning of Earth to the present, and its divisions chronicle some definitive events of Earth history. Earth formed around 4.54 billion years ago, approximately one-third the age of the universe, by accretion from the solar nebula. Volcanic outgassing probably created the primordial atmosphe…

Evidence: 43 • authority: 88

On the Origin of Life on Earth: The Nanozymes Hypothesis, and More. The origin of life (OoL) is a fundamental and long-standing scientific question. Although a variety of plausible hypotheses had been put forward, how life began on the prebiotic Earth from a pile of prehistoric inert chemicals (gases) is still a puzzle to us. Here, to unify the existing hypotheses to cover the entire scenarios, the author proposed the “nanozymes hypothesis” of the OoL on Earth, in which natural mineral nanozymes (MN-zymes) and their later upgraded organic/inorganic hybridized nanozymes played multiple key roles in the initial emergence of life molecules, especially in the manner of “inorganic photosynthesis…

Evidence: 43 • authority: 72

Rare Earth: Why Complex Life Is Uncommon in the Universe is a 2000 popular science book about xenobiology by Peter Ward, a geologist and evolutionary biologist, and Donald E. Brownlee, a cosmologist and astrobiologist. The book is the origin of the term 'Rare Earth Hypothesis' which denotes the central claim of the book: that complex life is rare in the universe.

Evidence: 38 • authority: 92

From Metal-Related Public Health Risks to Bioremediation: The Potential of the Polyextremophilic <i>Galdieria</i> spp.-A Systematic Review.. The growing demand for rare earth elements (REEs), heavy metals (HMs) and precious metals (PMs) has intensified interest in sustainable recovery strategies from secondary resources, including mining residues, industrial effluents and waste electrical and electronic equipment (WEEE). These streams represent exposure interfaces, because soluble and bioavailable metal species may persist, bioaccumulate and contribute to oxidative stress, genotoxicity, carcinogenic outcomes and chronic systemic effects. This systematic review, conducted followi…

Evidence: 33 • authority: 80

Mass Extinctions and the Rare Earth Hypothesis

Evidence: 33 • authority: 92

The Origin and Early Evolution of Fungi: Challenges, Inferences, and Principles.. Fungi are widespread on our planet and essential for life as we know it, but how did they come about? Their last common ancestor lived hundreds of millions of years ago, but its characteristics, and the contours of early fungal evolution, remain mysterious. This review synthesizes information from fungal and eukaryotic microbial diversity, geology, fossils, and evolutionary genomics to infer the early evolution of fungi, identify challenges and major gaps in our knowledge, dispel misconceptions, and propose general evolutionary principles exemplified by the fungal lineage. Even though fungi likely emerged earl…