scholarly journals Energy metabolism among eukaryotic anaerobes in light of Proterozoic ocean chemistry

2008 ◽  
Vol 363 (1504) ◽  
pp. 2717-2729 ◽  
Author(s):  
Marek Mentel ◽  
William Martin
Keyword(s):  
Energy Metabolism ◽  
Alternative Hypothesis ◽  
Atmospheric Oxygen ◽  
Global Scale ◽  
Evolutionary Significance ◽  
Significant Finding ◽  
Eukaryotic Evolution ◽  
Important Advance ◽  
The Earth ◽  
Ocean Chemistry

Recent years have witnessed major upheavals in views about early eukaryotic evolution. One very significant finding was that mitochondria, including hydrogenosomes and the newly discovered mitosomes, are just as ubiquitous and defining among eukaryotes as the nucleus itself. A second important advance concerns the readjustment, still in progress, about phylogenetic relationships among eukaryotic groups and the roughly six new eukaryotic supergroups that are currently at the focus of much attention. From the standpoint of energy metabolism (the biochemical means through which eukaryotes gain their ATP, thereby enabling any and all evolution of other traits), understanding of mitochondria among eukaryotic anaerobes has improved. The mainstream formulations of endosymbiotic theory did not predict the ubiquity of mitochondria among anaerobic eukaryotes, while an alternative hypothesis that specifically addressed the evolutionary origin of energy metabolism among eukaryotic anaerobes did. Those developments in biology have been paralleled by a similar upheaval in the Earth sciences regarding views about the prevalence of oxygen in the oceans during the Proterozoic (the time from ca 2.5 to 0.6 Ga ago). The new model of Proterozoic ocean chemistry indicates that the oceans were anoxic and sulphidic during most of the Proterozoic. Its proponents suggest the underlying geochemical mechanism to entail the weathering of continental sulphides by atmospheric oxygen to sulphate, which was carried into the oceans as sulphate, fuelling marine sulphate reducers (anaerobic, hydrogen sulphide-producing prokaryotes) on a global scale. Taken together, these two mutually compatible developments in biology and geology underscore the evolutionary significance of oxygen-independent ATP-generating pathways in mitochondria, including those of various metazoan groups, as a watermark of the environments within which eukaryotes arose and diversified into their major lineages.

HOW ANCIENT CAN HUMANITY BE?

2017 ◽  
Author(s):  
Vjacheslav Skosar ◽  
Keyword(s):  
Alternative Hypothesis ◽  
The Earth

The hypothesis of the African ancestral home of humanity and the time of the appearance of man is questioned. An alternative hypothesis is proposed, according to which people began to settle from the Armenian Highlands later 34 million years ago, then they lived east of Mesopotamia, after which they came to Mesopotamia and founded Babylon ~ 10-0.6 million years ago. After ~ 0.6 million years ago, there was a resettlement of people from Babylon throughout the earth, including the group that came to Africa at the same time. These data can be verified in further research.

The Strait of Magellan—a Gateway to New Worlds

2021 ◽  
Author(s):  
Mauricio Onetto Pavez
Keyword(s):  
Global Scale ◽  
Modern World ◽  
American Continent ◽  
The Earth ◽  
Starting Point ◽  
Strait Of Magellan ◽  
The World ◽  
The Strait Of Magellan ◽  
History Of ◽  
First Time

The year 2020 marks the five hundredth anniversary of the “discovery” of the Strait of Magellan. The unveiling of this passage between 1519 and 1522 allowed the planet to be circumnavigated for the first time in the history of humanity. All maritime routes could now be connected, and the idea of the Earth, in its geographical, cosmographic, and philosophical dimensions, gained its definitive meaning. This discovery can be considered one of the founding events of the modern world and of the process of globalization that still continues today. This new connectivity awoke an immediate interest in Europe that led to the emergence of a political consciousness of possession, domination, and territorial occupation generalized on a global scale, and the American continent was the starting point for this. This consciousness also inspired a desire for knowledge about this new form of inhabiting the world. Various fields of knowledge were redefined thanks to the new spaces and measurements produced by the discovery of the southern part of the Americas, which was recorded in books on cosmography, natural history, cartography, and manuscripts, circulating mainly between the Americas and Europe. All these processes transformed the Strait of Magellan into a geopolitical space coveted by Europeans during the 16th century. As an interoceanic connector, it was used to imagine commercial routes to the Orient and political projects that could sustain these dynamics. It was also conceived as a space to speculate on the potential wealth in the extreme south of the continent. In addition, on the Spanish side, some agents of the Crown considered it a strategic place for imperial projections and the defense of the Americas.

scholarly journals Contributing to the progress of descriptive taxonomy

Zootaxa ◽  
2008 ◽  
Vol 1968 (1) ◽  
pp. 65-68 ◽  
Author(s):  
ZHI-QIANG ZHANG
Keyword(s):  
Phylogenetic Analysis ◽  
Molecular Systematics ◽  
Rapid Growth ◽  
Animal Species ◽  
Global Scale ◽  
Grass Roots ◽  
The Earth ◽  
The World ◽  
Molecular Studies ◽  
Types Of Information

One of the fundamental quests of biology is discovering how many species inhabit the Earth. Yet the vast majority of the world’s animal species are waiting to be discovered, named and described—estimates of the total number vary from 5 to 30 million.  Most biologists would agree that taxonomy is important and fundamental to credible biology, and descriptive taxonomy is the most important task of taxonomy (Wheeler 2007). Unfortunately, the reality is that descriptive taxonomy has been marginalized since the mid-1950s and has sustained serious losses in funding and academic positions in universities and museums around the world, especially since phylogenetic and molecular studies became popular in the last twenty years.  During this period, there has also been an important historical trend in taxonomic publishing—many journal publishers/editors have been making increasing demands on authors to provide phylogenetic analysis, molecular systematics, and other modern types of information in taxonomic papers. In addition, there are long publication delays and/or increasing page charges for many journals that do publish descriptive taxonomic papers. Zootaxa was founded in 2001 to provide a much-needed outlet for descriptive taxonomic papers and monographs that are difficult to publish elsewhere, and as a result has received tremendous support from taxonomists worldwide, despite the fact that it is a grass-roots project without support from government and institutions (Zhang 2006a).  Zootaxa satisfied the publishing need of many zoological taxonomists, and sustained a period of rapid growth during 2001 to 2006 (Zhang 2006b). During the last two years, it has continued to grow in size, and especially in its impact, and has become a major force in reviving descriptive taxonomy on a global scale.  Here I summarize some encouraging data on the growth of Zootaxa and its impact.  I also comment on its contribution to the progress of  descriptive taxonomy.

Analysis of Composite Structure and Primordial Wood Remains in Petrified Wood

2007 ◽  
Vol 61 (8) ◽  
pp. 889-895 ◽  
Author(s):  
J. Nowak ◽  
D. Nowak ◽  
P. Chevallier ◽  
J. Lekki ◽  
R. van Grieken ◽  
...  
Keyword(s):  
Cell Walls ◽  
Central Italy ◽  
Global Scale ◽  
Mineralization Process ◽  
Raman Spectrometry ◽  
X Ray ◽  
The Earth ◽  
Geological Past ◽  
Petrified Wood ◽  
Composite Nature

Among all the fossils, petrified wood belongs to the most impressive and most common of materials. Still, its study has not exceeded the purely phenomenological level. The recognition of the conserved structure of petrified wood seems to be of meaning for understanding the geological past, the complete carbon cycle inside the Earth, and the structure of potential new materials. The first ever published spatial distributions of the remains of the primordial organic material (lignin, cellulose, pectins) in the cells of permineralized wood, from Dunarobba (Central Italy), are presented here. They were collected using μ-Raman spectrometry. The composite nature of the petrified material (calcite located in the lumena of cells and goethite located in the cell walls) was confirmed by electron, proton, and X-ray microprobes. The structure of the cell walls was well preserved. The mineralization process was induced by the tracheidal water flow and was stopped after formation of pipe-like goethite shielding of the cell walls on the cellulose scaffolds. The chemical (Eh and pH ranges) and probable microbial conditions for such a pattern of mineralization were determined. We estimate that substantial amounts of the primordial organic matter were preserved in bodies of petrified wood on a global scale. The wood petrifaction process, if well understood, can be a basis for the production of “everlasting” organic–inorganic composite compounds.

Costing the Earth: A Numbers Game or a Moral Imperative?

2013 ◽  
Vol 5 (4) ◽  
pp. 378-380 ◽  
Author(s):  
Gerard Roe
Keyword(s):  
Climate Change ◽  
Regional Climate ◽  
Relative Weight ◽  
Global Scale ◽  
Climate Impacts ◽  
Economic Consequences ◽  
Economic Costs ◽  
Policy Makers ◽  
The Earth ◽  
Moral Arguments

Abstract It is a simple truism that public policy must be guided by an objective analysis of the physical and economic consequences of climate change. It is equally true that policy making is an inherently value-laden endeavor. While these two threads are interconnected, the relative weight given to each depends on the certainty that the technical analyses can deliver. For climate change, the envelope of uncertainty is best understood at the global scale, and there are some well known and formidable challenges to reducing it. This uncertainty must in turn be compounded with much more poorly constrained uncertainties in regional climate, climate impacts, and future economic costs. The case can be made that technical analyses have reached the point of diminishing returns. Should meaningful action on climate change await greater analytical certainty? This paper argues that policy makers should give greater weight to moral arguments, in no small part because that is where the heart of the debate really lies.

scholarly journals Thermodynamycal evolution of the Earth and Mars with formation of ocean, free atmospheric oxygen and generation of life

2012 ◽  
Vol 8 (1) ◽  
pp. 49-54
Author(s):  
R.Ya. Belevtsev ◽  
K.I. Churyumov ◽  
S.D. Spivak ◽  
Е.K. Melnik
Keyword(s):  
Atmospheric Oxygen ◽  
The Earth

scholarly journals Temporal variation of planetary iron as a driver of evolution

2021 ◽  
Vol 118 (51) ◽  
pp. e2109865118
Author(s):  
Jon Wade ◽  
David J. Byrne ◽  
Chris J. Ballentine ◽  
Hal Drakesmith
Keyword(s):  
Iron Acquisition ◽  
Atmospheric Oxygen ◽  
Genetic Selection ◽  
Transition Element ◽  
Global Scale ◽  
Biochemical Properties ◽  
Element Distribution ◽  
Iron Bioavailability ◽  
Geological Time ◽  
Core Mass

Iron is an irreplaceable component of proteins and enzyme systems required for life. This need for iron is a well-characterized evolutionary mechanism for genetic selection. However, there is limited consideration of how iron bioavailability, initially determined by planetary accretion but fluctuating considerably at global scale over geological time frames, has shaped the biosphere. We describe influences of iron on planetary habitability from formation events >4 Gya and initiation of biochemistry from geochemistry through oxygenation of the atmosphere to current host–pathogen dynamics. By determining the iron and transition element distribution within the terrestrial planets, planetary core formation is a constraint on both the crustal composition and the longevity of surface water, hence a planet’s habitability. As such, stellar compositions, combined with metallic core-mass fraction, may be an observable characteristic of exoplanets that relates to their ability to support life. On Earth, the stepwise rise of atmospheric oxygen effectively removed gigatons of soluble ferrous iron from habitats, generating evolutionary pressures. Phagocytic, infectious, and symbiotic behaviors, dating from around the Great Oxygenation Event, refocused iron acquisition onto biotic sources, while eukaryotic multicellularity allows iron recycling within an organism. These developments allow life to more efficiently utilize a scarce but vital nutrient. Initiation of terrestrial life benefitted from the biochemical properties of abundant mantle/crustal iron, but the subsequent loss of iron bioavailability may have been an equally important driver of compensatory diversity. This latter concept may have relevance for the predicted future increase in iron deficiency across the food chain caused by elevated atmospheric CO2.

scholarly journals Pedagogical Values of Renaissance Travels

2015 ◽  
Vol 49 ◽  
pp. 185-191
Author(s):  
Agnieszka Katarzyna Gębora
Keyword(s):  
Sixteenth Century ◽  
Social Life ◽  
Educational Development ◽  
Global Scale ◽  
Foreign Languages ◽  
New Model ◽  
Culture Area ◽  
The Earth ◽  
The Social

The time of the Renaissance created the new model of the man-humanist. European patterns stimulated to the cultural or educational development of different fields of the social life. A bloom of the education took place, a thirst for knowledge, an interest in learning, world, travels, getting new experiences. A man educated, being good at foreign languages, opened for changes was appreciated. Geographical discoveries and their effects forever changed the image of the earth. Sixteenth-century peregrinations contributed to the development of states, economic and civilization expansion, and the bloom of culture area. Pedagogic meaning of Renaissance journeys is indisputable. Experience from voyages all over world, extending ranges, the permeation of cultures, the learning of foreign languages, the increase in the knowledge, the development of learning, education and artistic fields bear fruit to this day in the global scale.

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