Lunine (US), Jean-Marc Petit (IT), Francois Robert (FR), Giovanni B. Cyr (US) proposed that as the solar system formed, Jupiter's powerful gravity perturbed asteroids to accrete into larger and larger objects resulting in terrestrial "embyros" near the size of Mars. Towe (US), Edward Anders (US), Gustaf Olaf Arrhenius (SE-US), Bibhas Ranjan De (US), Hannes Olof Gosta Alfvén (SE-US), Anne Benlow (GB), Arthur Jack Meadows (GB), Manfred A. Ahrens (US) proposed that on the primitive Earth, impact accretions from extraterrestrial objects represented a significant source of atmospheric and biogenic elements (75, 113, 223, 233, 697, 1393, 1927, 2309, 2366). This "greenhouse" would have offset the effects of a faint young Sun which was dimmer than today’s by 25-30%. Grotzinger (US) used greenhouse calculations and the sedimentary record to suggest that prior to 3.8 Ga the Earth’s surface was a warm (80-100˚C), with a bicarbonate-rich ocean at a p H perhaps as low as 6 (1020, 1307, 1484). Francis Harry Compton Crick (GB), Sydney Brenner (ZA-GB), Aaron Klug (ZA-GB), and George Pieczenik (US) proposed that the assignment of codons to particular amino acids was simply an historical accident. Initially E was plentiful in the environment and was absorbed directly by primitive aggregates. These "embryos were tossed into very unstable elliptical orbits with the result that some collided with Earth thereby delivering the water that now fills Earth's oceans. Climate models confirm that 100-1,000 times the present atmospheric level of carbon dioxide would have been necessary to produce the ancient "greenhouse" effect (1307). Allègre (FR), Thomas Staudacher (FR), and Philippe Sarda (FR) determined that early catastrophic out-gassing occurred on the young Earth (54, 2352). Walker (US) and Peter Brimblecombe (GB) found that abundant aqueous ferrous iron occurring in an oceanic hydrothermal system results in the precipitation of otherwise highly insoluble iron sulfides. There being no special reasons why a particular codon stands for a given amino acid (557). Later, as E became scarce because of use, chemical selection favored pre-cells that could make E from D, a slightly less complex organic substance still found in abundance in the environment. Mémoire sur les accidents des Coquilles fossiles, comparés à ceux qui arrivent aux Coquilles qu’on trouve maintenant dans la mer [Memory of accident fossil shells, compared to those who arrive in the shells now found in the sea]. These events occurred when Earth was about half its present size (1655). Arvid Gustaf Högbom (SE) suggested that Earth's primitive atmosphere resulted from gradual, episodic, or rapid volcanic out-gassing and weathering (1179). This would have released significant amounts of nitrogen, carbon dioxide, carbon monoxide, methane, water, hydrogen, sulfur dioxide, and hydrogen sulfide. This suggests that on the primitive Earth such a system would have served as a highly effective sink for hydrogen sulfide (2553). Wood (GB) and David Virgo (US) presented evidence that Earth's primitive atmosphere was poised at a redox state buffered close to the fayalite-quartz-magnetite system, which is consistent with a neutral redox atmosphere and characteristic of basalts throughout the geological record (2649). As D became exhausted, selection favored assemblies that developed the pathway C to D to E, in which the even simpler substance C could be absorbed and used as raw material to make D. Memoires de l'Academie des Sciences, Paris: 189-226; 329-57; 99-419 1027.

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John Burdon Sanderson Haldane (GB-IN), Harold Clayton Urey (US) and John Desmond Bernal (GB) also forwarded the same hypothesis (232, 1046, 2395). He also concluded that an anaerobic hyperthermophilic autotroph was very likely the original cell type (2265). They believe these tiny holes were etched by microorganisms, ca. This changed the notion of evolutionary unity among prokaryotes.

This is often called the heterotroph hypothesis of the origin of life. (US) and Stanley Lloyd Miller (US) made the argument that the Earth’s primitive atmosphere was virtually devoid of oxygen (498, 1630). Towe (US) made a compelling case that the Earth’s early atmosphere contained significant quantities of oxygen (2367). Günter Wächtershäuser (DE) presented a hypothesis supporting chemoautotrophy as the first form of metabolism to appear within life forms on the primitive Earth. Dunlop (AU), Joseph John Edmund Glover (AU), David I. The phylogenetic data support the very early appearance of the eukaryotic nuclear line of descent. Peattie (US) determined that the diplomonad Giardia lamblia 16S-like r RNA has retained many of the features that may have been present in the common ancestor of eukaryotes (Eucarya) and prokaryotes (Archaea or Bacteria).

He argued that these life forms were coatings that adhered to the positively charged surfaces of pyrite, a mineral composed of iron and sulfur. Groves (AU), and Roger Buick (AU) concluded from their studies of sedimentary rocks in Western Australia that near 3.5 Ga there existed a shallow marine environment dominated by episodic island volcanism and hydrothermal activity (164, 1023). The Eucarya is as old as the prokaryotic lines Archaea and Bacteria. They concluded that it represents the earliest-branching eukaryotic lineage (2208). Brocks (AU), and Roger Buick (AU) found molecular fossils of biological lipids preserved in 2,700-million-year-old shales from the Pilbara Craton, Australia. The presence of abundant 2 alpha-methylhopanes, which are characteristic of cyanobacteria, indicates that oxygenic photosynthesis evolved well before the atmosphere became oxidizing. Walter (US), Du Rulin (US), and Robert Joseph Horodyski (US) had previously discovered multi-cellular fossils (c.1.4 Ga) in old Greyson Shale, lower Belt Supergroup, in Montana, US, and from the similarly aged Gaoyuzhuang Formation, upper Changcheng Group, in the Jixian section, Northern China.

In contrast to the nebular-gas-cloud theory this theory held that Earth formed by accretion of small, cold bodies (dust and asteroids) (463, 1675). Stevenson (US), Takafumi Matsui (JP), and Yutaka Abe (JP) reasoned that the Earth with its metallic core, highly convective mantle, molten surface, and massive steam atmosphere, formed as a direct result of accretion (13, 1576, 2267). Pashley (AU) found membrane-forming non-polar molecules within the Murchison carbonaceous chondritic meteorite (696). Epps (US) reported the synthesis of phospholipids under primitive Earth conditions (1749). Kasting (US) showed that photochemistry in an atmosphere containing carbon dioxide or a mixture of carbon monoxide and carbon dioxide yielded formaldehyde as a major product (156, 1306, 1851). Exposure of the mixture to ultraviolet or visible light resulted in the direct synthesis of ATP (352). Deamer (US) found that fatty acids and glycerol combine spontaneously to produce phospholipids when heated to dryness at 65°C, as they might have been in an evaporating tide pool along a primitive sea (1070). Dworkin (US) and Juan Oró (US) synthesized uridine diphosphate glucose, cytidine diphosphate choline, other phosphorylated metabolic intermediates, the coenzymes adenosine diphosphate glucose (ADPG), guanosine diphosphate glucose (GDPG), and cytidine diphosphoethanolamine (CDP-ethanolamine) under primitive Earth conditions (1548, 1549). Woese (US), Francis Harry Compton Crick (GB), and Leslie Eleazer Orgel (GB-US) suggested that it would have been possible in a pre-DNA world to have a primitive replicating and catalytic apparatus devoid of both DNA and proteins and based solely on RNA molecules, i.e., an RNA world (556, 1744, 2639). This reaction demonstrates the feasibility of RNA-catalyzed RNA replications and supports the RNA world hypothesis (737).

Immanuel Kant (DE) had proposed much earlier that the Earth formed by condensation (1302, 1303). Williams (US) identified the oldest rocks found on Earth as granite-like rocks called gneiss from the Acasta Gneiss Complex near Great Slave Lake, Northwest Territory, Canada. The Isua Supracrustal rocks in West Greenland are a close second at 3.7 to 3.8 Ga. Kimball (US) synthesized adenine, thymine, amino acids, and other biochemical compounds from HCN in a primitive Earth environment (1746, 1747, 2264). Stanley Lloyd Miller (US), in Harold Clayton Urey’s (US) laboratory, showed that a wet mixture of methane, hydrogen, and ammonia exposed to electrical discharge for a while, formed traces of organic compounds, including organic acids and amino-acids regarded as exclusive components of living things (1629). Christopher Reid (GB), Leslie Eleazer Orgel (GB-US), and Cyril Ponnamperuma (LK-US) have shown that random processes can form nucleotides and dinucleotides. John Desmond Bernal (GB) proposed that one way in which organic subunits may spontaneously combine into larger molecules is by adsorption of the reacting molecules onto the highly ordered negatively charged aluminosilicates of clays. Walker () also proposed that under primitive Earth conditions organic polymers could have condensed on extremely thin layers of negatively charged aluminosilicates separated by layers of water (419). Joshi (US), and Juan Oró (US) produced polynucleotide polymers under primitive Earth conditions (2263). Bruce Michael Alberts (US), Walter Gilbert (US), and Antonio Lazcano (MX) proposed that DNA and proteins were derived from RNA-based cells or cell-like units (40, 962, 1409). De l'Hevrevx Accovchement des Femmes, ov il est Traicte du Gouuernement de leur Grossesse, de levr Travail Naturel et Contre Nature, du Traictement Estant Accouchees, et de leurs Maladies [The Happy Childbirth Women, or it is the Tract Governing their Pregnancy , their Labor Against Natural and Nature, the Document on Surviving Birth, and its Diseases].

Clair Cameron Patterson (US), George Tilton (US), and Mark Ingham (US) used uranium decay in rocks from Earth and in meteorites that struck Earth to date our solar system at 4.55 billion years old (1807-1809). These rocks were dated using the uranium 235 to lead 207 method (325). Master (US) synthesized amino acids from formaldehyde and hydroxylamine under primitive Earth conditions (1748). They have also demonstrated the formation of ATP through the ultimate agency of solar energy (1950). The clay surface performs a catalytic function (231, 232). Sidney Walter Fox (US), Kaoru Harada (JP), and Allen Vegotsky (US) showed how amino acids can be heated under Earth conditions to form proteinoids or "thermal proteins," which when placed in water self-organize into microspheres or protocells, possible precursors of the contemporary living cell (892-895). (US) and Juan Oró (US) synthesized peptides under plausible primitive Earth conditions (1095). Antonio Lazcano (MX) postulated that DNA evolved to replace RNA as the repository of hereditary information because, 1) DNA is much more resistant to harsh environmental conditions, 2) DNA is less prone to mutations which cannot be repaired, 3) cytosines in DNA are not as prone to spontaneously deaminate to uracil as they are in RNA, and 4) the duplex nature of DNA offered redundancy, which when coupled with repair mechanisms had a distinct advantage over simplex RNA without a repair mechanism (1410). Woese (US) originally described the progenote as the last common ancestor for archaebacteria (Archaea), eubacteria (Bacteria), and eukaryotes (Eucarya).

Alessandro Morbidelli (IT), John Chambers (US), Jonathan I. Pollack (US), and David Crisp (US) concluded that to keep the oceans from freezing on the primitive Earth a global "greenhouse" was necessary. Noam Lahav (IL), David White (US), and Sherwood Chang (US) experimentally produced peptide bonds under conditions where clay, water, and amino acids were subjected to cyclic variations in temperature and water content (1381). It contained informational polymers, could synthesize polypeptides, and was still evolving a link between genotype and phenotype (2640, 2641). Walter (US), speculated that life on Earth might have arisen as early as 3.9 Ga (2122). Hubbard (US) proposed how complex sequential metabolic pathways may have arisen as the result of selective pressure. Suppose that a contemporary cellular pathway makes a required substance such as an amino acid through the sequence A to B to C to D to E, in which A is a simple inorganic substance and E is the final organic product. Sur les anthérozoides et la double copulation sexuelle chez les végétaux angiospermes [On antherozoids and the double sexual copulation in angiosperm plants].

A Selected Chronological Bibliography of Biology and Medicine — Part I 13.75 Ga — 1809 Compiled by James Southworth Steen, Ph. Delta State University Dedicated to my loving family This document celebrates those secondary authors and laboratory technicians without whom most of this great labor of discovery would have proved impossible. This theory is now known popularly as the Big Bang Theory, a phrase coined by Fred Hoyle (GB) in a moment of facetiousness, during a radio broadcast (1209). Bennett (US) and a team from the National Aeronautics and Space Administration (NASA) and the Goddard Space Flight Center in Maryland announced that the age of the universe is 13.7 Ga with a one percent margin for error (458, 544). Lawrence Hugh Aller (US) concluded that nucleosyntheses in stellar interiors generates carbon, nitrogen, oxygen, phosphorus, and other biogenic elements (57). It states that the solar system formed because, "God sent adrift a number of ‘vortices’ of swirling gas, and these eventually made the stars, which later changed themselves into comets, which in turn still later formed themselves into planets" (711). Forhandlinger: Videnskabs-Selskabet i Christiana 1: 35-45 1031.

This primal atom rapidly expanded for circa 10-20 Ga scattering matter and energy in all directions (540, 1353, 1437). Fowler (US), and Fred Hoyle (GB) suggested that the heavier elements are formed in supernova explosions (410). René Descartes (FR), in 1644, proposed the Nebular Hypothesis. Studier over affiniteten [Studies on the affinity]. Études sur les Affinités Chimiques [Studies on Chemical Affinities].

Professor of Biology Delta State University Box 3262, Cleveland, MS 38733 e-mail: [email protected]“Reason was born, as it has since now discovered, into a world already wonderfully organized, in which it found its precursor in what is called life, its seat in an animal body of unusual plasticity, and its function in rendering that body’s volatile instincts and sensations harmonious with one another and with the outer world on which they depend.” George Santayana (2061) "The proper concern of natural science is not what God could do if he wished, but what he has done; that is, what happens in the world according to the inherent causes of nature." Albertus Magnus; Alberti Magni; Albert the Great (DE) (1004, 2020) Georges Eduard Lemaitre (BE) proposed that the universe began as a primal atom, an incredibly dense egg containing all the material for the universe within a sphere about 30 times larger than our Sun. E., was the first to teach that all heavenly bodies were brought into existence by the same processes that formed the earth and that all of these objects are made of the same materials (74).

Thomas Chowder Chamberlin (US) and Forest Ray Moulton (US) developed the Chamberlin-Moulton planetesimal hypothesis to explain the origin of the Earth and other planetary bodies. Lawless (US), Katherine Pering (US), Etta Peterson (US), Jose Flores (US), Cyril Ponnamperuma (LK-US), Isaac R. Cronin (US) examined the Murchison carbonaceous chondritic meteorite and found racemic mixtures of 74 different amino acids: Eight that are present in proteins, eleven with other biological roles (including, quite surprisingly, some neurotransmitters), and fifty-five that have been found almost exclusively in extraterrestrial samples (559, 1374, 1375). Stephen-Sherwood (US), Joseph Eichberg (US), and Dennis E. Randall Gladstone (US), Yuk Ling Yung (US), Akiva Bar-Nun (IL), Sherwood Chang (US), and James F. Wang (US) mixed a porphyrin, AMP, and inorganic phosphate with an imidazole group as a catalyst. Szostak (US) found that the Tetrahymena ribozyme could splice together multiple oligonucleotides aligned on a template strand to yield a fully complementary product strand.