Search results for " Darwin"

Global distributions of diazotrophs Gamma-A nifH genes abundance - Depth integrated values computed from a collection of source datasets - Contributi…

2013

The MAREDAT atlas covers 11 types of plankton, ranging in size from bacteria to jellyfish. Together, these plankton groups determine the health and productivity of the global ocean and play a vital role in the global carbon cycle. Working within a uniform and consistent spatial and depth grid (map) of the global ocean, the researchers compiled thousands and tens of thousands of data points to identify regions of plankton abundance and scarcity as well as areas of data abundance and scarcity. At many of the grid points, the MAREDAT team accomplished the difficult conversion from abundance (numbers of organisms) to biomass (carbon mass of organisms). The MAREDAT atlas provides an unprecedente…

Production of methyl mercury in the gut of the Australian termite Mastotermes darwiniensis

2008

Animals are often exposed to or can ingest heavy metals along with their food. Therefore, we tested whether the hindgut microbiota of Mastotermes darwiniensis possesses the capability to form methyl mercury. The termite M. darwiniensis (Isoptera) was fed with saw dust containing different concentrations of inorganic mercury. Methyl mercury was determined by purge-and-trap capillary gas chromatography-atom fluorescence spectrometry (CGC-AFS) using ethyl mercury chloride as the internal standard. Total mercury concentrations were determined in the termite tissue by inductive coupled plasma-isotope dilution mass spectrometry (ICP-IDMS) after microwave-assisted digestion. The obtained results s…

Contribution to the reconstruction of geological evolution of the metamorphic basement of the Cordillera Darwin, Tierra del Fuego, Chile.

2008

The crystalline pre-Andine basement outcrops only in the Cordillera Darwin (Tierra del Fuego) in the extreme southern part of Andean belt. It is located between the Antarctic, Nazca and Scotia Plate. Cordillera Darwin breaks the long ophiolitic belt constituted by the Sarmiento Complex and Rocas Verdes; many authors agree that the present setting is the result of the Andean orogenesis, that yielded to the closure of a Jurassic marginal basin (now represented by ophiolites) with its overlying sequence of rhyolitic volcanic and volcanoclastic rocks, now represented by the Tobifera Formation and metamorphism during Cretaceous (Cunningham, 1995 and references). The studied rocks, sampled by A.D…

Ethidium bromide: a fast fluorescent staining procedure for the detection of symbiotic partnership of flagellates and prokaryotes

1999

The hindgut of 'lower' termites harbors a dense population of flagellates and bacteria. The flagellates possess ecto- and endosymbiotic prokaryotes. Most of them are hardly visible in the phase contrast microscope. Staining with the DNA-intercalating agent ethidium bromide visualizes the nuclei of the flagellates as well as the ecto- and endosymbiotic bacteria as red objects. Furthermore, it is possible to distinguish between endosymbiotic methanogens and other bacteria. Following UV excitation, the blue-green autofluorescence of the methanogenic bacteria eclipses the red fluorescence light of the intercalated ethidium bromide. The dye facilitates the observation of symbiotic bacteria and h…

Evolutionary biology and beliefs : how ideology can draw different social stances from science

2016

Agreeing that there are often strong connections between fields of science and the ideological convictions of those producing the science, this essay shows that the connections are often complex and rarely straightforward. Taking the example of evolutionary biology, by looking at three key figures ? Herbert Spencer, Charles Darwin and Alfred Russel Wallace ? it is shown how very different social beliefs can lead to very different social conclusions being drawn from one?s science. It is argued that this message should be kept firmly in mind by those who today would draw social conclusions from science, for instance suggesting that Darwinian evolutionary biology leads straight to the social p…

Charles Darwin and ideology : rethinking the Darwinian revolution

2016

This short paper critiques the idea of any coherent Darwinian ideology. Charles Darwin himself did not adopt any obvious ideology, except perhaps that of anti-slavery. However, his published work, and that of other evolutionists, led to the emergence of social Darwinism. Herbert Spencer’s role in fostering social Darwinism, and the rise of eugenics, are briefly described. The connection, if any, between the historical figure of Darwin and the social movement that bears his name is discussed. While Darwin’s On the origin of species or The descent of man can hardly account for all the racial stereotyping, nationalism, or political bigotry seen in the half century after his death, there can be…

Homo Natura. Autoregolazione e caos nel pensiero di Nietzsche

2005

Evolution education in natural history museums

2009

During 2009, scientists around the world will celebrate the 200th anniversary of the birth of Charles Darwin, the father of the theory of evolution, and the 150th anniversary of the publication of his main thesis, On the Origin of Species by Means of Natural Selection. Today, the theory of evolution is considered to be one of the greatest milestones in the history of science. Despite its undisputed merit in science, there seems to be constant turmoil around the theory in the public, which might be related to the incomplete understanding of the basic principles of evolution [1,2].

Comparative Genomics of Blattabacterium cuenoti: The Frozen Legacy of an Ancient Endosymbiont Genome

2013

Many insect species have established long-term symbiotic relationships with intracellular bacteria. Symbiosis with bacteria has provided insects with novel ecological capabilities, which have allowed them colonize previously unexplored niches. Despite its importance to the understanding of the emergence of biological complexity, the evolution of symbiotic relationships remains hitherto a mystery in evolutionary biology. In this study, we contribute to the investigation of the evolutionary leaps enabled by mutualistic symbioses by sequencing the genome of Blattabacterium cuenoti, primary endosymbiont of the omnivorous cockroach Blatta orientalis, and one of the most ancient symbiotic associa…

Anti-Zeno-based dynamical control of the unfolding of quantum Darwinism

2020

We combine the collisional picture for open system dynamics and the control of the rate of decoherence provided by the quantum (anti-)Zeno effect to illustrate the temporal unfolding of the redundant encoding of information into a multipartite environment that is at the basis of Quantum Darwinism, and to control it. The rate at which such encoding occurs can be enhanced or suppressed by tuning the dynamical conditions of system-environment interaction in a suitable and remarkably simple manner. This would help the design of a new generation of quantum experiments addressing the elusive phenomenology of Quantum Darwinism and thus its characterization.