Asa de mariposa: isolante acústico natural de eficiência imbatível: mero acaso, fortuita necessidade ou design inteligente?

 Moth wings as sound absorber metasurface

Thomas R. Neil, Zhiyuan Shen, Daniel Robert, Bruce W. Drinkwater and Marc W. Holderied

Published:15 June 2022 https://doi.org/10.1098/rspa.2022.0046

Image/Imagem: University of Bristol

Abstract

In noise control applications, a perfect metasurface absorber would have the desirable traits of not only mitigating unwanted sound, but also being much thinner than the wavelengths of interest. Such deep-subwavelength performance is difficult to achieve technologically, yet moth wings, as natural metamaterials, offer functionality as efficient sound absorbers through the action of the numerous resonant scales that decorate their wing membrane. Here, we quantify the potential for moth wings to act as a sound-absorbing metasurface coating for acoustically reflective substrates. Moth wings were found to be efficient sound absorbers, reducing reflection from an acoustically hard surface by up to 87% at the lowest frequency tested (20 kHz), despite a thickness to wavelength ratio of up to 1/50. Remarkably, after the removal of the scales from the dorsal surface the wing's orientation on the surface changed its absorptive performance: absorption remains high when the bald wing membrane faces the sound but breaks down almost completely in the reverse orientation. Numerical simulations confirm the strong influence of the air gap below the wing membrane but only when it is adorned with scales. The finding that moth wings act as deep-subwavelength sound-absorbing metasurfaces opens the door to bioinspired, high-performance sound mitigation solutions.

FREE PDF GRATIS: Proceddings of the Royal Society A

Origem e evolução inicial da célula eucariótica

Origin and Early Evolution of the Eukaryotic Cell

Annual Review of Microbiology

Vol. 75:631-647 (Volume publication date October 2021)

First published as a Review in Advance on August 3, 2021

https://doi.org/10.1146/annurev-micro-090817-062213 

Image/Imagem

Toni Gabaldón1,2,3

1Barcelona Supercomputing Centre (BCS-CNS), 08034 Barcelona, Spain; email: toni.gabaldon.bcn@gmail.com

2Institute for Research in Biomedicine (IRB), The Barcelona Institute of Science and Technology (BIST), 08028 Barcelona, Spain

3Catalan Institution for Research and Advanced Studies (ICREA), 08010 Barcelona, Spain

Abstract

The origin of eukaryotes has been defined as the major evolutionary transition since the origin of life itself. Most hallmark traits of eukaryotes, such as their intricate intracellular organization, can be traced back to a putative common ancestor that predated the broad diversity of extant eukaryotes. However, little is known about the nature and relative order of events that occurred in the path from preexisting prokaryotes to this already sophisticated ancestor. The origin of mitochondria from the endosymbiosis of an alphaproteobacterium is one of the few robustly established events to which most hypotheses on the origin of eukaryotes are anchored, but the debate is still open regarding the time of this acquisition, the nature of the host, and the ecological and metabolic interactions between the symbiotic partners. After the acquisition of mitochondria, eukaryotes underwent a fast radiation into several major clades whose phylogenetic relationships have been largely elusive. Recent progress in the comparative analyses of a growing number of genomes is shedding light on the early events of eukaryotic evolution as well as on the root and branching patterns of the tree of eukaryotes. Here I discuss current knowledge and debates on the origin and early evolution of eukaryotes. I focus particularly on how phylogenomic analyses have challenged some of the early assumptions about eukaryotic evolution, including the widespread idea that mitochondrial symbiosis in an archaeal host was the earliest event in eukaryogenesis.

Keywords eukaryogenesis, mitochondria, endosymbiosis, eukaryotic evolution, LECA

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As mitocôndrias e a origem dos eucariontes

 

Mitochondria and the origin of eukaryotes

Were the powerhouse organelles a driving force or a late addition in the evolution of more complex cells like ours?

By Viviane Callier 06.08.2022

For billions of years after the origin of life, the only living things on Earth were tiny, primitive cells resembling today’s bacteria. But then, more than 1.5 billion years ago, something remarkable happened: One of those primitive cells, belonging to a group known as the archaea, swallowed a different one — a bacterium.

Instead of being digested, the bacterium took up permanent residence within the other organism as what biologists call an endosymbiont. Eventually, it integrated fully into its archaeal host cell, becoming what we know today as the mitochondrion, the crucial energy-producing component of the cell.

Its acquisition has long been viewed as the key step in what is arguably the most important evolutionary leap since the origin of life itself: the transition from early primitive cells, or prokaryotes, to the more sophisticated cells of higher organisms, or eukaryotes, including ourselves.

It’s a neat story you’ll find in most biology textbooks — but is it quite that simple? In the last few years, new evidence has challenged the notion that mitochondria played a seminal role in this transition. Researchers sequencing the genomes of modern-day relatives of the first eukaryotes have found many unexpected genes that don’t seem to come from either the host or the endosymbiont. And that, some scientists suggest, might mean that the evolution of the first eukaryotes involved more than two partners and happened more gradually than suspected.

Others don’t see a reason yet to abandon the theory that the acquisition of the mitochondrion was the spark that ignited the rapid evolution of eukaryotes — giving rise, eons later, to plants, animals, vertebrates, people. Fresh evidence from genomics and cell biology may help resolve the debate, while also pointing to knowledge gaps that still need to be filled to understand one of the foundational events in our own ancestry, the origin of complex cells.

Read more here/Leia mais aqui: Knowable Magazine

Darwin, nós temos um problema: a fisiologia restaura o propósito na biologia evolutiva

Physiology restores purpose to evolutionary biology

Raymond Noble, Denis Noble

Biological Journal of the Linnean Society, blac049, 

Published: 08 June 2022 

Article history Received: 26 November 2021 Revision received: 02 April 2022 Accepted: 08 April 2022

Published: 08 June 2022

Image/Imagem

Abstract

Life is purposefully creative in a continuous process of maintaining integrity; it adapts to counteract change. This is an ongoing, iterative process. Its actions are essentially directed to this purpose. Life exists to exist. Physiology is the study of purposeful living function. Function necessarily implies purpose. This was accepted all the way from William Harvey in the 17th century, who identified the purpose of the heart to pump blood and so feed the organs and tissues of the body, through many 19th and early 20th century examples. But late 20th century physiology was obliged to hide these ideas in shame. Teleology became the ‘lady who no physiologist could do without, but who could not be acknowledged in public.’ This emasculation of the discipline accelerated once the Central Dogma of molecular biology was formulated, and once physiology had become sidelined as concerned only with the disposable vehicle of evolution. This development has to be reversed. Even on the practical criterion of relevance to health care, gene-centrism has been a disaster, since prediction from elements to the whole system only rarely succeeds, whereas identifying whole system functions invariably makes testable predictions at an elemental level.

Key words biological function, Central Dogma, purpose in biology, teleology

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Físicos reescrevem a lei fundamental que leva à desordem

Physicists Rewrite the Fundamental Law That Leads to Disorder

The second law of thermodynamics is among the most sacred in all of science, but it has always rested on 19th century arguments about probability. New arguments trace its true source to the flows of quantum information.

Is the rise of entropy merely probabilistic, or can it be straightened out by use of clear quantum axioms?

Maggie Chiang for Quanta Magazine

In all of physical law, there’s arguably no principle more sacrosanct than the second law of thermodynamics — the notion that entropy, a measure of disorder, will always stay the same or increase. “If someone points out to you that your pet theory of the universe is in disagreement with Maxwell’s equations — then so much the worse for Maxwell’s equations,” wrote the British astrophysicist Arthur Eddington in his 1928 book The Nature of the Physical World. “If it is found to be contradicted by observation — well, these experimentalists do bungle things sometimes. But if your theory is found to be against the second law of thermodynamics I can give you no hope; there is nothing for it but to collapse in deepest humiliation.” No violation of this law has ever been observed, nor is any expected.

But something about the second law troubles physicists. Some are not convinced that we understand it properly or that its foundations are firm. Although it’s called a law, it’s usually regarded as merely probabilistic: It stipulates that the outcome of any process will be the most probable one (which effectively means the outcome is inevitable given the numbers involved).

Yet physicists don’t just want descriptions of what will probably happen. “We like laws of physics to be exact,” said the physicist Chiara Marletto of the University of Oxford. Can the second law be tightened up into more than just a statement of likelihoods?

A number of independent groups appear to have done just that. They may have woven the second law out of the fundamental principles of quantum mechanics — which, some suspect, have directionality and irreversibility built into them at the deepest level. According to this view, the second law comes about not because of classical probabilities but because of quantum effects such as entanglement. It arises from the ways in which quantum systems share information, and from cornerstone quantum principles that decree what is allowed to happen and what is not. In this telling, an increase in entropy is not just the most likely outcome of change. It is a logical consequence of the most fundamental resource that we know of — the quantum resource of information.

Quantum Inevitability

Thermodynamics was conceived in the early 19th century to describe the flow of heat and the production of work. The need for such a theory was urgently felt as steam power drove the Industrial Revolution, and engineers wanted to make their devices as efficient as possible.

In the end, thermodynamics wasn’t much help in making better engines and machinery. Instead, it became one of the central pillars of modern physics, providing criteria that govern all processes of change.

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Read more here/Leia mais aqui: Quanta Magazine

Darwin, estudo sugere que a maioria das árvores evolutivas pode estar errada...

Molecular phylogenies map to biogeography better than morphological ones

Jack W. Oyston, Mark Wilkinson, Marcello Ruta & Matthew A. Wills 

Communications Biology volume 5, Article number: 521 (2022)

Schematic universal tree updated from (Woese et al., 1990)

Abstract

Phylogenetic relationships are inferred principally from two classes of data: morphological and molecular. Currently, most phylogenies of extant taxa are inferred from molecules and when morphological and molecular trees conflict the latter are often preferred. Although supported by simulations, the superiority of molecular trees has rarely been assessed empirically. Here we test phylogenetic accuracy using two independent data sources: biogeographic distributions and fossil first occurrences. For 48 pairs of morphological and molecular trees we show that, on average, molecular trees provide a better fit to biogeographic data than their morphological counterparts and that biogeographic congruence increases over research time. We find no significant differences in stratigraphic congruence between morphological and molecular trees. These results have implications for understanding the distribution of homoplasy in morphological data sets, the utility of morphology as a test of molecular hypotheses and the implications of analysing fossil groups for which molecular data are unavailable.

FREE PDF GRATIS: Communications Biology 

O neodarwinismo deve mudar se quiser sobreviver

Neo-Darwinism must Mutate to survive

Olen R.Brown a David A.Hullender b

a Dalton Cardiovascular Research Center, University of Missouri- Columbia, USA

b Professor of Mechanical and Aerospace Engineering at the University of Texas at Arlington, USA

Received 15 November 2021, Revised 6 April 2022, Accepted 12 April 2022, Available online 16 April 2022.

https://doi.org/10.1016/j.pbiomolbio.2022.04.005 

Image/Imagem: BioScience

Abstract

Darwinian evolution is a nineteenth century descriptive concept that itself has evolved. Selection by survival of the fittest was a captivating idea. Microevolution was biologically and empirically verified by discovery of mutations. There has been limited progress to the modern synthesis. The central focus of this perspective is to provide evidence to document that selection based on survival of the fittest is insufficient for other than microevolution. Realistic probability calculations based on probabilities associated with microevolution are presented. However, macroevolution (required for all speciation events and the complexifications appearing in the Cambrian explosion) are shown to be probabilistically highly implausible (on the order of 10−50) when based on selection by survival of the fittest. We conclude that macroevolution via survival of the fittest is not salvageable by arguments for random genetic drift and other proposed mechanisms. Evolutionary biology is relevant to cancer mechanisms with significance beyond academics. We challenge evolutionary biology to advance boldly beyond the inadequacies of the modern synthesis toward a unifying theory modeled after the Grand Unified Theory in physics. This should include the possibility of a fifth force in nature. Mathematics should be rigorously applied to current and future evolutionary empirical discoveries. We present justification that molecular biology and biochemistry must evolve to aeon (life) chemistry that acknowledges the uniqueness of enzymes for life. To evolve, biological evolution must face the known deficiencies, especially the limitations of the concept survival of the fittest, and seek solutions in Eigen's concept of self-organization, Schrödinger's negentropy, and novel approaches.

Keywords Evolution Modern synthesis Negentropy Probability Selection Selforganization Survival of fittest

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Progress in Biophysics and Molecular Biology

Darwin, mais turbulência na base da Árvore da Vida - eucariogênese, o surgimento de um superorganismo emergente

Eukaryogenesis: The Rise of an Emergent Superorganism

Philip J. L. Bell*

Microbiogen Pty Ltd., Sydney, NSW, Australia

Image/Imagem: Wiley Online Library

Although it is widely taught that all modern life descended via modification from a last universal common ancestor (LUCA), this dominant paradigm is yet to provide a generally accepted explanation for the chasm in design between prokaryotic and eukaryotic cells. Counter to this dominant paradigm, the viral eukaryogenesis (VE) hypothesis proposes that the eukaryotes originated as an emergent superorganism and thus did not evolve from LUCA via descent with incremental modification. According to the VE hypothesis, the eukaryotic nucleus descends from a viral factory, the mitochondrion descends from an enslaved alpha-proteobacteria and the cytoplasm and plasma membrane descend from an archaeal host. A virus initiated the eukaryogenesis process by colonising an archaeal host to create a virocell that had its metabolism reprogrammed to support the viral factory. Subsequently, viral processes facilitated the entry of a bacterium into the archaeal cytoplasm which was also eventually reprogrammed to support the viral factory. As the viral factory increased control of the consortium, the archaeal genome was lost, the bacterial genome was greatly reduced and the viral factory eventually evolved into the nucleus. It is proposed that the interaction between these three simple components generated a superorganism whose emergent properties allowed the evolution of eukaryotic complexity. If the radical tenets of the VE hypothesis are ultimately accepted, current biological paradigms regarding viruses, cell theory, LUCA and the universal Tree of Life (ToL) should be fundamentally altered or completely abandoned.

FREE PDF GRATIS: Frontiers in Microbiology