O papel do Darwinismo no pensamento racial nazista, de Richard Weikart

quinta-feira, outubro 31, 2013

The Role of Darwinism in Nazi Racial Thought

Richard Weikart

Historians disagree about whether Nazis embraced Darwinian evolution. By examining Hitler’s ideology, the official biology curriculum, the writings of Nazi anthropologists, and Nazi periodicals, we find that Nazi racial theorists did indeed embrace human and racial evolution. They not only taught that humans had evolved from primates, but they believed the Aryan or Nordic race had evolved to a higher level than other races because of the harsh climatic conditions that influ- enced natural selection. They also claimed that Darwinism underpinned specific elements of Nazi racial ideology, including racial inequality, the necessity of the racial struggle for existence, and collectivism.1

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Novo experimento vai lançar luz sobre o mistério da massa escura no Universo

sexta-feira, outubro 25, 2013

Transmission of Megawatt Relativistic Electron Beams Through Millimeter Apertures

R. Alarcon, S. Balascuta, S.V. Benson, W. Bertozzi, J.R. Boyce, R. Cowan, D. Douglas, P. Evtushenko, P. Fisher, E. Ihloff, N. Kalantarians, A. Kelleher, R. Legg, R.G. Milner, G.R. Neil, L. Ou, B. Schmookler, C. Tennant, C. Tschalaer, G.P. Williams, S. Zhang

(Submitted on 1 May 2013)

High power, relativistic electron beams from energy recovery linacs have great potential to realize new experimental paradigms for pioneering innovation in fundamental and applied research. A major design consideration for this new generation of experimental capabilities is the understanding of the halo associated with these bright, intense beams. In this Letter, we report on measurements performed using the 100 MeV, 430 kWatt CW electron beam from the energy recovery linac at the Jefferson Laboratory's Free Electron Laser facility as it traversed a set of small apertures in a 127 mm long aluminum block. Thermal measurements of the block together with neutron measurements near the beam-target interaction point yielded a consistent understanding of the beam losses. These were determined to be 3 ppm through a 2 mm diameter aperture and were maintained during a 7 hour continuous run.

Comments: 10 pages, 5 figures

Subjects: Accelerator Physics (physics.acc-ph); High Energy Physics - Experiment (hep-ex); Nuclear Experiment (nucl-ex)

Cite as: arXiv:1305.0199 [physics.acc-ph]

(or arXiv:1305.0199v1 [physics.acc-ph] for this version)

Submission history

From: Richard Milner [view email] 

[v1] Wed, 1 May 2013 15:17:23 GMT (437kb,D)

FREE PDF GRATIS: ArXiv

Nova hipótese evolucionária: evolução baseada em interação - como que a seleção natural e a mutação não aleatória trabalham juntas

quinta-feira, outubro 24, 2013

Hypothesis

Interaction-based evolution: how natural selection and nonrandom mutation work together

Adi Livnat

Correspondence: Adi Livnat adi@vt.edu

Author Affiliations

Biology Direct 2013, 8:24 doi:10.1186/1745-6150-8-24

Published: 18 October 2013

Abstract (provisional)

Background

The modern evolutionary synthesis leaves unresolved some of the most fundamental, long-standing questions in evolutionary biology: What is the role of sex in evolution? How does complex adaptation evolve? How can selection operate effectively on genetic interactions? More recently, the molecular biology and genomics revolutions have raised a host of critical new questions, through empirical findings that the modern synthesis fails to explain: for example, the discovery of de novo genes; the immense constructive role of transposable elements in evolution; genetic variance and biochemical activity that go far beyond what traditional natural selection can maintain; perplexing cases of molecular parallelism; and more.

Presentation of the hypothesis

Here I address these questions from a unified perspective, by means of a new mechanistic view of evolution that offers a novel connection between selection on the phenotype and genetic evolutionary change (while relying, like the traditional theory, on natural selection as the only source of feedback on the fit between an organism and its environment). I hypothesize that the mutation that is of relevance for the evolution of complex adaptation?while not Lamarckian, or "directed" to increase fitness?is not random, but is instead the outcome of a complex and continually evolving biological process that combines information from multiple loci into one. This allows selection on a fleeting combination of interacting alleles at different loci to have a hereditary effect according to the combination's fitness.

Testing the hypothesis

Empirical evidence for the proposed mechanism from both molecular evolution and evolution at the organismal level is discussed, and multiple predictions are offered by which it may be tested.

Implications of the hypothesis

This proposed mechanism addresses the problem of how beneficial genetic interactions can evolve under selection, and also offers an intuitive explanation for the role of sex in evolution, which focuses on sex as the generator of genetic combinations. Importantly, it also implies that genetic variation that has appeared neutral through the lens of traditional theory can actually experience selection on interactions and thus has a much greater adaptive potential than previously considered.

Reviewers: This article was reviewed by Nigel Goldenfeld (nominated by Eugene V. Koonin), Jurgen Brosius and W. Ford Doolittle.

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FREE PDF GRATIS: Biology Direct

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EXCERPT/EXCERTO:

"...it is commonly assumed that traditional natural selection operates to the extent that it can, and that originally neutral mutations account for anything that selection does not account for. But this modern approach leads to a deep inconsistency. The original idea of natural selection and random mutation, implicit in Fisher’s work, was to minimize the amount of 'work' done by chance in the evolution of adaptation and let natural selection do the job of evolving an adaptation by pulling out from the noise the supposed slightly beneficial mutations and causing them to accumulate inexorably toward the evolution of adaptation. It is inconsistent to invoke this idea, which attempted to minimize the amount of evolutionary work done by fortuitous chance, while at the same time allowing for an unspecified number of originally neutral mutations to play an inherent role in the evolution of adaptation, as is currently done for example in the case of de novo genes. Indeed, there is no quantification of the amount of chance that we call upon to explain the evolution of adaptation (namely the chance that is involved in the arising of accidental mutations and in random genetic drift, to the extent that the latter is invoked)—a deep problem not yet addressed at all by the whole body of population genetics."

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NOTA DESTE BLOGGER:

Quando escrevo aqui que a teoria da evolução de Darwin através da seleção natural e n mecanismos evolucionários (de A a Z, vai que...), a Galera dos meninos e meninas de Darwin reage dizendo que eu não entendo o componente teórico da teoria da evolução. A cada dia os evolucionistas me vindicam com suas pesquisas. Ah, como é bom ser vindicado por evolucionistas. Sinal de que estou em boa companhia, pelo menos no que diz respeito ao status heurístico de uma teoria que não se corrobora no contexto de justificação teórica desde 1859.


Fui, nem sei por que, rindo igual o gato de Cheshire...

Variação genética críptica pode fazer a complexidade irredutível em um modo comum de adaptação - mas não citam ao Michael Behe

Cryptic Genetic Variation Can Make Irreducible Complexity a Common Mode of Adaptation

Meredith V. Trotter, Daniel B. Weissman, Grant I. Peterson, Kayla M. Peck, Joanna Masel

(Submitted on 22 Oct 2013)



The existence of complex (multiple-step) genetic adaptations that are "irreducible" (i.e., all partial combinations are less fit than the original genotype) is one of the longest standing problems in evolutionary biology. In standard genetics parlance, these adaptations require the crossing of a wide adaptive valley of deleterious intermediate stages. Here we demonstrate, using a simple model, that evolution can cross wide valleys to produce "irreducibly complex" adaptations by making use of previously cryptic mutations. When revealed by an evolutionary capacitor, previously cryptic mutants have higher initial frequencies than do new mutations, bringing them closer to a valley-crossing saddle in allele frequency space. Moreover, simple combinatorics imply an enormous number of candidate combinations exist within available cryptic genetic variation. We model the dynamics of crossing of a wide adaptive valley after a capacitance event using both numerical simulations and analytical approximations. Although individual valley crossing events become less likely as valleys widen, by taking the combinatorics of genotype space into account, we see that revealing cryptic variation can cause the frequent evolution of complex adaptations. This finding also effectively dismantles "irreducible complexity" as an argument against evolution by providing a general mechanism for crossing wide adaptive valleys.


Subjects: Populations and Evolution (q-bio.PE)

Cite as: arXiv:1310.6077 [q-bio.PE]

(or arXiv:1310.6077v1 [q-bio.PE] for this version)

Submission history

From: Meredith Trotter [view email] 

[v1] Tue, 22 Oct 2013 23:34:57 GMT (989kb)

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FREE PDF GRATIS: ArXiv

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EXCERPT/EXCERTO

"When a population is well adapted to its environment, the vast majority of new mutations will be neutral or negative. If a higher fitness genotype exists that requires multiple mutations, but each intermediate mutation combination is deleterious, the population must traverse a metaphorical "adaptive valley" of low fitness to access the superior adaptation (Wright 1932). Such adaptations are called "irreducibly complex" by the intelligent design lobby, which uses the term to assert that evolution cannot cross multi-step adaptive valleys. Detailed investigations into the evolution of specific complex adaptations (Bridgham et al. 2006; Weinreich et al. 2006; PoelwijkFJ et al. 2007; Egelman 2010) have shown that in these particular cases, evolved complexity is not irreducible. Many biologists assume, in agreement with the intelligent design lobby, that irreducible complexity rarely, if ever, evolves."


NOTA DESTE BLOGGER:

Repare que neste artigo que afirma ter desmantelado o conceito de "complexidade irredutível" como argumento contra a evolução gradualista darwinista, nenhuma vez cita Michael Behe. NOTA BENE: NENHUMA VEZ! A não ser pejorativamente - intelligent design lobby!

Ora, se é ;obby, como que que você se propõe demonstrar cientificamente falso a tese do Design Inteligente se você não cita um trabalho do seu oponente? Estranho esse comportamento dos autores.

Todavia, nessa tentativa de falsificar a tese do Design Inteligente, em termos popperianos, esses autores estão confirmando que a tese do DI é uma tese científica, pois se sujeita à falsificação/falseamento. Mas não citar quem trouxe para o centro do discussão científica a complexidade irredutível de sistemas biológicos é CENSURA DITATORIAL da Nomenklatura que não vê, não ouve nem fala em Design Inteligente. Só quando lhe convém!

Ah, adaptação não explica a macroevolução - um Australopithecus afarensis se transmutar em Antropólogo amazonense... E sem isso, Darwin continua blefando teoricamente...

Torquemadas pós-modernos, chiques e perfumados a la Dawkins...

Pobre ciência...

Os cientistas ainda não sabem as origens evolucionárias dos dinossauros...

ANDREW HOWE/GETTY IMAGES

“As origens evolucionárias do dinossauro, por exemplo, ainda são um mistério. Pesquisadores estão tentando avidamente determinar como que esses reis do período Cretáceo (que se estendeu por 145 a 66 milhões de anos atrás) surgiram de uma linha de dinossauros pequeninos durante o período Jurássico (201 a 145 milhões de anos atrás).”

“The dinosaur's evolutionary origins, for example, are still a mystery. Researchers are eagerly trying to determine how these kings of the Cretaceous period (which spanned from 145 million to 66 million years ago) arose from a line of tiny dinosaurs during the Jurassic period (201 million to 145 million years ago).”

FREE PDF GRATIS: Nature

Razão do blog Desafiando a Nomenklatura científica: explodir o senso comum e os dogmas centrais de paradigmas colapsantes

Perguntaram-me certa vez qual a razão do meu blog Desafiando a Nomenklatura científica. Respondi que a razão estava explicitada no meu perfil. Hoje, parafraseando Demétrio Magnoli, novo colunista da Folha de São Paulo, dou a razão atualizada do meu blog: 

"Meu blog visa explodir o senso comum, os dogmas centrais. Escrever contra o óbvio, contra as verdades estabelecidas, especialmente nestes tempos em que a linguagem científica dos críticos e oponentes dos paradigmas estabelecidos foi esvaziada".

Não existe nenhum fossil conhecido de hominídeo ancestral de Neanderthais e humanos modernos

segunda-feira, outubro 21, 2013

No known hominin species matches the expected dental morphology of the last common ancestor of Neanderthals and modern humans

Aida Gómez-Roblesa,b,1, José María Bermúdez de Castroc, Juan-Luis Arsuagad, Eudald Carbonelle, and P. David Pollyf

Author Affiliations

aDepartment of Anthropology, The George Washington University, Washington, DC 20052;
bKonrad Lorenz Institute for Evolution and Cognition Research, A-3422 Altenberg, Austria;
cCentro Nacional de Investigación sobre la Evolución Humana, 09002 Burgos, Spain;
dCentro de Investigación Sobre la Evolución y Comportamiento Humanos, Universidad Complutense de Madrid–Instituto de Salud Carlos III, 28029 Madrid, Spain;
eInstitut Català de Paleoecologia Humana i Evolució Social, Universitat Rovira i Virgili, 43007 Tarragona, Spain; and
fDepartments of Geological Sciences, Biology, and Anthropology, Indiana University, Bloomington,IN 47405

Edited by Jukka Jernvall, University of Helsinki, Helsinki, Finland, and accepted by the Editorial Board September 19, 2013 (received for review February 9, 2013)



Significance

The identity of the last common ancestor of Neanderthals and modern humans is a controversial issue. This debate has been often addressed by means of descriptive analyses that are difficult to test. Our primary aim is to put questions about human evolution into a testable quantitative framework and to offer an objective means to sort out apparently unsolvable debates about hominin phylogeny. Our paper shows that no known hominin species matches the expected morphology of this common ancestor. Furthermore, we found that European representatives of potential ancestral species have had affinities with Neanderthals for almost 1 My, thus supporting a model of early divergence between Neanderthals and modern humans.

Abstract

A central problem in paleoanthropology is the identity of the last common ancestor of Neanderthals and modern humans ([N-MH]LCA). Recently developed analytical techniques now allow this problem to be addressed using a probabilistic morphological framework. This study provides a quantitative reconstruction of the expected dental morphology of the [N-MH]LCA and an assessment of whether known fossil species are compatible with this ancestral position. We show that no known fossil species is a suitable candidate for being the [N-MH]LCA and that all late Early and Middle Pleistocene taxa from Europe have Neanderthal dental affinities, pointing to the existence of a European clade originated around 1 Ma. These results are incongruent with younger molecular divergence estimates and suggest at least one of the following must be true: (i) European fossils and the [N-MH]LCA selectively retained primitive dental traits; (ii) molecular estimates of the divergence between Neanderthals and modern humans are underestimated; or (iii) phenotypic divergence and speciation between both species were decoupled such that phenotypic differentiation, at least in dental morphology, predated speciation.

phylogeny node reconstruction geometric morphometrics morphospace European Pleistocene

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SUBSCRIPTION OR PAYMENT NEEDED: PNAS

Professores, pesquisadores e alunos de universidades públicas e privadas com acesso ao site CAPES/Periódicos podem ler este artigo do PNAS e mais 22.440 publicações científicas.

Reducionismo e complexidade em biologia molecular: Chamem a turma do Design Inteligente!!!

Reductionism and complexity in molecular biology

Marc H.V. Van Regenmortel

Additional article information

Summary

Scientists now have the tools to unravel biological complexity and overcome the limitations of reductionism

The reductionist method of dissecting biological systems into their constituent parts has been effective in explaining the chemical basis of numerous living processes. However, many biologists now realize that this approach has reached its limit. Biological systems are extremely complex and have emergent properties that cannot be explained, or even predicted, by studying their individual parts. The reductionist approach—although successful in the early days of molecular biology—underestimates this complexity and therefore has an increasingly detrimental influence on many areas of biomedical research, including drug discovery and vaccine development.

The claim made by Francis Crick (1966) that “The ultimate aim of the modern movement in biology is to explain all biology in terms of physics and chemistry” epitomizes the reductionist mindset that has pervaded molecular biology for half a century. The theory is that because biological systems are composed solely of atoms and molecules, without the influence of 'alien' or 'spiritual' forces, it should be possible to explain them using the physicochemical properties of their individual components, down to the atomic level. The most extreme manifestation of the reductionist view is the belief that is held by some neuroscientists that consciousness and mental states can be reduced to chemical reactions that occur in the brain (Bickle, 2003; Van Regenmortel, 2004).

Reductionists analyse a larger system by breaking it down into pieces and determining the connections between the parts. They assume that the isolated molecules and their structure have sufficient explanatory power to provide an understanding of the whole system. As the value of methodo-logical reductionism hasbeen particularly evident in molecular biology, it might seem odd that, in recent years, biologists have become increasingly critical of the idea that biological systems can be fully explained using physics and chemistry. Their situation is similar to that of an art student asking about the significance of Michelangelo's David and being told that it is just a piece of marble hewn into a statue in 1504. This is certainly true, but it evades pertinent questions about the anatomy of the statue, its creation at the beginning of the Florentine Renaissance, its significance in European art history, or even the scars on its left arm that were plastered after it was broken in three places during the anti-Medici revolt of 1527. In an analogous way, the biology, development, physiology, behaviour or fate of a human being cannot be adequately explained along reductionist lines that consider only chemical composition. Anti-reductionists therefore regard biology as an autonomous discipline that requires its own vocabulary and concepts that are not found in chemistry and physics. Both sides have discussed their standpoints at several recent international meetings (Bock & Goode, 1998; Van Regenmortel & Hull, 2002; Van Regenmortel, 2004) and the main disagreement between the protagonists is about what constitutes a good scientific explanation.

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A evolução darwinista é “indispensável” para a Biologia?

sábado, outubro 19, 2013

Michael Egnor 18 de outubro de 2013 4:28 PM | Permalink

Larry Moran tem uma postagem divertida sobre a evolução como um dos novos conceitos fundamentais em bioquímica e biologia molecular. Se você tem que proclamar periodicamente ao mundo da indispensabilidade de sua disciplina científica, então sua disciplina científica não é indispensável. 

Da American Society for Biochemistry and Molecular Biology, com meu comentário:

A Importância Central da Teoria da Evolução em todas as Ciências Biológicas 

“Assim como é para todas as ciências biológicas, a evolução é um conceito fundamental em bioquímica e biologia molecular”.

A evolução é irrelevante para a bioquímica e biologia molecular. A bioquímica e a biologia molecular são, é claro, bem importantes no desenvolvimento de uma compreensão da história evolucionária. O nosso entendimento da história evolucionária é dependente (em grande parte) na bioquímica e biologia molecular. Afirmar a dependência reversa é raciocinar em círculo. 

“Um entendimento da história evolucionária partilhada por todos os sistemas vivos em nosso planeta é assim crítica para qualquer estudante dessas disciplinas”.

Vide acima. A bioquímica e a biologia molecular são uma grande parte da evidência da evolução. Portanto, a evolução não pode ser uma grande parte da evidência para a bioquímica e biologia molecular. 

“A teoria evolucionária guia os esforços experimentais através da bioquímica e biologia molecular.”

Bobagem. As inferências evolucionárias, se boas ou más estórias, são irrelevantes para pesquisa em bioquímica e biologia molecular. Muito, se não a maior parte da pesquisa em bioquímica e biologia molecular é conduzida em escolas de medicina, que não ensinam biologia evolucionária e não têm departamentos de biologia evolucionária.

“Isso varia da comparação de enzimas relacionadas de espécies diferentes pela identificação de resíduos de sítios ativos fundamentais...”

A bioquímica e a biologia molecular pode ser usada para inferir ancestralidade comum evolucionária (o design comum também é uma inferência razoável). A inferência para a ancestralidade evolucionária baseada na bioquímica e biologia molecular não pode então contribuir para a pesquisa em bioquímica e biologia molecular, porque, conforme destacado acima, isso seria raciocinar em círculo. 

“... até ao uso de comparações interespécies na determinação de funções de genes...”

Idem.

“até a procura de genes responsáveis para doenças genéticas usando abordagens filogenéticos para o estudo de mecanismos reguladores que guiam o desenvolvimento.”

As doenças têm causas próximas e evolucionárias. Os bioquímicos e biólogos moleculares estudam causas próximas. Os biólogos evolucionistas inventam estórias evolucionárias baseada na pesquisa de causas próximas. A contribuição é unidirecional.

“Nossas tentativas em compreender as moléculas humanas e processos são imensamente aprimoradas pela nossa compreensão de seus contrapartes em outros organismos.”

A similaridade entre humanos e outros organismos é estabelecida pela bioquímica, biologia molecular, fisiologia, anatomia, etc. Baseadas em similaridades, as inferências evolucionárias são invocadas pelos biólogos evolucionistas. Se os bioquímicos etc. afirmassem que as estórias evolucionárias fossem essenciais ao seu trabalho, eles estariam... raciocinando em círculo. Mas, é claro, eles na verdade não afirmam isso. Eles apenas prestam homenagem à evolução para manter longe os darwinistas. 

“Nossos esforços em lidar com um novo patógeno humano – viral, bacteriano, ou eucariótico – são aprimorados incomensuravelmente por prévios estudos de vírus ou organismos relacionados ao patógeno.”

“Relacionados” é determinado pela bioquímica e a biologia molecular. As estórias evolucionárias sobre relacionalidade são derivadas das similaridades bioquímicas e moleculares. Portanto, a evolução é informada pela, mas não informa, bioquímica e biologia molecular.

O comentário saliente sobre esses louvores tolos à evolução foram feitos por um importante biólogo molecular e membro da National Academy of Sciences dos Estados Unidos, Philip Skell:

“[A] forma moderna da teoria de Darwin foi elevada ao seu atual status elevado porque dizem ser a pedra angular da biologia experimental moderna. Mas isso é correto? “Embora a grande maioria dos biólogos, provavelmente, concordaria com a máxima de Theodosius Dobzhansky de que ‘nada em biologia faz sentido a não ser à luz da evolução’, a maioria pode conduzir seu trabalho bem felizmente sem referência particular às ideias evolucionárias”, A.S. Wilkins, editor do journal BioEssays, escreveu em 2000. “A evolução pareceria ser a ideia unificadora indispensável e, ao mesmo tempo, uma ideia altamente supérflua”.

Eu tenderia concordar. Certamente, minha pesquisa com antibióticos durante a Segunda Guerra Mundial não recebeu nenhuma orientação dos insights fornecidos pela evolução darwinista. Nem a descoberta da inibição bacteriana pela penicilina por Alexander Fleming. Recentemente eu perguntei a mais de 70 pesquisadores eminentes se eles teriam feito seu trabalho diferentemente se eles tivessem pensado que a teoria de Darwin estivesse errada. As respostas foram todas a mesma: Não. 

Eu também examinei as descobertas biológicas prominentes do século passado: a descoberta da dupla hélice [do DNA]; a caracterização do ribossomo; o mapeamento dos genomas; pesquisas em reações a remédios e drogas; melhoras na produção de alimentos e saneamento público; o desenvolvimento de novas cirurgias; e outras. Eu até perguntei biólogos trabalhando em áreas onde alguém esperaria o paradigma darwinista ter mais beneficiado a pesquisa, tal como o surgimento de resistência a antibióticos e pesticidas. Aqui, e em outras áreas, eu descobri que a teoria de Darwin não tinha fornecido nenhuma direção discernível, mas foi trazida, após as descobertas, como um verniz narrativo interessante.”

As afirmações circulares absurdas da indispensabilidade da evolução para as disciplinas biológicas – as próprias ciências nas quais a biologia evolucionária se alimenta – é mais evidência de que o verniz narrativo darwinista está usando é tão fino que a evolução precisa de uma maratona telivisiva aqui e ali para torná-la parecer relevante.

Crânio de Homo erectus bagunça a estória da evolução humana!

sexta-feira, outubro 18, 2013

Skull of Homo erectus throws story of human evolution into disarray

A haul of fossils found in Georgia suggests that half a dozen species of early human ancestor were actually all Homo erectus

Ian Sample, science correspondent

theguardian.com, Thursday 17 October 2013 19.00 BST


The spectacular fossilised skull of an ancient human ancestor that died nearly two million years ago in central Asia has forced scientists to rethink the story of early human evolution.

Anthropologists unearthed the skull at a site in Dmanisi, a small town in southern Georgia, where other remains of human ancestors, simple stone tools and long-extinct animals have been dated to 1.8m years old.

Experts believe the skull is one of the most important fossil finds to date, but it has proved as controversial as it is stunning. Analysis of the skull and other remains at Dmanisi suggests that scientists have been too ready to name separate species of human ancestors in Africa. Many of those species may now have to be wiped from the textbooks.

The latest fossil is the only intact skull ever found of a human ancestor that lived in the early Pleistocene, when our predecessors first walked out of Africa. The skull adds to a haul of bones recovered from Dmanisi that belong to five individuals, most likely an elderly male, two other adult males, a young female and a juvenile of unknown sex.


The five H erectus skulls found in Dmanisi, Georgia. Photograph: Ponce de León, Zollikofe/University of Zurich

The site was a busy watering hole that human ancestors shared with giant extinct cheetahs, sabre-toothed cats and other beasts. The remains of the individuals were found in collapsed dens where carnivores had apparently dragged the carcasses to eat. They are thought to have died within a few hundred years of one another.

"Nobody has ever seen such a well-preserved skull from this period," said Christoph Zollikofer, a professor at Zurich University's Anthropological Institute, who worked on the remains. "This is the first complete skull of an adult early Homo. They simply did not exist before," he said. Homo is the genus of great apes that emerged around 2.4m years ago and includes modern humans.

Other researchers said the fossil was an extraordinary discovery. "The significance is difficult to overstate. It is stunning in its completeness. This is going to be one of the real classics in paleoanthropology," said Tim White, an expert on human evolution at the University of California, Berkeley.

But while the skull itself is spectacular, it is the implications of the discovery that have caused scientists in the field to draw breath. Over decades excavating sites in Africa, researchers have named half a dozen different species of early human ancestor, but most, if not all, are now on shaky ground.
...

Read more here/Leia mais aqui: The Guardian

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NOTA DESTE BLOGGER:

Quando da descoberta em Dmanisi, Geórgia, eu disse que eles seriam demonstrados como sendo da mesma espécie. Riram de mim! Como é bom ser vindicado por evolucionistas!!!

Pano rápido! Pois não é apenas o um elo perdido, mas toda uma corrente perdida. E o pior de tudo isso é que eles sabem...

Pobre ciência sequestrada pelo naturalismo filosófico que posa como se fosse ciência. Nada mais falso!

O naturalismo metodológico: verdadeira camisa de força epistemológica

quarta-feira, outubro 16, 2013

As operações em ciência feitas sob o naturalismo metodológico, o único princípio metodológico aceito pelos cientistas dentro do contexto das pesquisas científicas – todas as hipóteses e eventos devem ser explicados e testados somente por referência a causas e eventos naturais. 


Pergunta causticante deste blogger: Não é o caso de os que fazem ciência já terem se decidido sobre quais tipos de coisas e eventos existem antes mesmo de começarem suas investigações/pesquisas?

Isso é ciência? E se outros tipos de coisas e eventos existirem, nós nunca saberemos por causa desta camisa de força epistemológica?

Leandro Russovski Tessler impediria Lynn Margulis de palestrar na Unicamp

Lynn Margulis foi uma bióloga evolucionista de renome, membro da Academia Nacional de Ciências dos Estados Unidos. Ela não apoiava, e criticava a teoria do Design Inteligente. Em uma entrevista concedida à DiscoverMagazine, ela disse por que é cética da evolução explicada pelo neodarwinismo, e admitiu expressamente que muito de suas críticas ao neodarwinismo são as mesmas feitas pelos proponentes do Design Inteligente (DI).

Primeiro ela explica por que discorda da adequação explanatória da mutação e seleção natural:

“Esta é a questão que eu tenho com os neodarwinistas: Eles ensinam que o que está produzindo a novidade é o acúmulo de mutações aleatórias no DNA, em uma direção estabelecida pela seleção natural. Se você quiser ovos maiores, você continua selecionando as galinhas que estão pondo os ovos maiores, e você consegue ovos cada vez maiores. Mas você também consegue galinhas com penas defeituosas e pernas bambas. A seleção natural elimina, e talvez mantenha, mas não cria... Os neodarwinistas dizem que novas espécies surgem quando ocorrem as mutações e elas modificam um organismo. Eu fui ensinada diversas vezes que o acúmulo de mutações aleatórias resultava em mudança evolucionária – resultaria em novas espécies. Eu acreditava nisso até que procurei por evidência.”

Neste raciocínio, quando questionada sobre os estudos famosos de evolução dos Grants sobre os tentilhões das ilhas Galápagos, ela declarou: “Eles viram muitas variações dentro de uma espécie, mudanças ao longo do tempo. Mas nunca descobriram quaisquer novas espécies – jamais.”

Quando questionada sobre “Que tipo de evidência a levou contra o neodarwinismo?”, ela respondeu que foi a falta de evidência de mudança gradual no registro fóssil:

“Aquela que você gostaria de ver em um bom caso a favor da mudança gradual de uma espécie para outra no campo, no laboratório, ou no registro fóssil – e preferivelmente em todos os três. O grande mistério de Darwin foi porque não havia nenhum registro antes de um ponto específico [datado em 542 milhões de anos atrás pelos pesquisadores modernos], e então subitamente no registro fóssil você tem quase que todos os principais tipos de animais. 

Os paleontólogos Niles Eldredge e Stephen Jay Gould pesquisaram lagos na África Oriental e nas ilhas do Caribe procurando as mudanças graduais de Darwin de uma espécie de trilobitas ou caramujos em outra espécie. O que eles acharam foi bastante variação alternante na população e depois – BANG – uma nova espécie. Não há gradualismo no registro fóssil.”

Os críticos de Darwin são tolerados na Academia?

Naquela entrevista, Margulis compartilhou algumas experiências pessoais sobre se ela foi intimidada por suas posições não darwinistas. Ela explica que “quem for abertamente crítico dos fundamentos de sua ciência é persona non grata. Eu sou crítica da biologia evolucionária que é baseada na genética de populações.”

Impressionante, enquanto materialistas que desafiam o neodarwinismo aparentemente são considerados “persona non grata”, Margulis explica que os cientistas que continuam procurando explicações darwinistas rapidamente irão receber recursos e apoio, mesmo admitindo que o paradigma está colapsando:

“Richard Lewontin, geneticista de populações, deu uma palestra aqui na Universidade de Massachusetts, Amherst, cerca de seis anos atrás, e ele a matematizou completamente – mudanças na população, mutação aleatória, seleção sexual, custo e benefício. No fim da palestra, ele disse, “Sabe de uma coisa, nós tentamos testar essas ideias no campo e no laboratório, e realmente não existe medidas que combinem com as quantidades das quais lhes falei”. Isso simplesmente me deixou perplexa. Então eu disse, “Richard Lewontin, você é um grande palestrante em ter a coragem de dizer que isso não lhe levou a lugar nenhum. Mas então por que você continua a fazer este trabalho?” Ele olhou ao redor e disse, “É a única coisa que eu sei como fazer, e se eu não fizer, eu não recebo dinheiro para pesquisa”. 

Aqui nós temos um homem honesto e uma resposta honesta...

Leandro Russovski Tessler impediria Lynn Margulis de palestrar na Unicamp... 

Aqui nós temos um exemplo vergonhoso de acadêmico desonesto que não está a par do estado heurístico colapsante da atual teoria da evolução, e que vem aí uma nova teoria geral da evolução - a SÍNTESE EVOLUTIVA AMPLIADA, que será anunciada somente em 2020 (não será selecionista e deverá incorporar aspectos teóricos neo-lamarckistas, para desespero de Darwin), e que fomenta a INQUISIÇÃO SEM FOGUEIRAS na Academia contra os críticos de Darwin e proponentes da teoria do Design Inteligente.

Um Torquemada pós-moderno, chique e perfumado a la Dawkins, que não quer o debate livre de ideias na universidade... 

Pobre ciência! 

Quase um milagre...

terça-feira, outubro 15, 2013

“Close to a miracle”

Researchers are debating whether function or structure first appeared in primitive peptides

By Rajendrani Mukhopadhyay

Proteins traverse the width and breadth of cells to carry signals and cargo from one end to another, package and replicate DNA, build scaffolds to give cells their shapes, break down and take up nutrients, and so much more. But how often do we stop to ask: How did these diverse and sophisticated molecular machines come to be?

Despite proteins' profound impact on life, their origin is not well understood. What caused a string of amino acids to start doing something? Or are strings of amino acids inherently programmed to do things? These are questions with which researchers in the protein-origin field have been grappling.

Researchers have a better grasp of the processes of selection and evolution once a function appears in a peptide. “Once you have identified an enzyme that has some weak, promiscuous activity for your target reaction, it’s fairly clear that, if you have mutations at random, you can select and improve this activity by several orders of magnitude,” says Dan Tawfik at the Weizmann Institute in Israel. “What we lack is a hypothesis for the earlier stages, where you don’t have this spectrum of enzymatic activities, active sites and folds from which selection can identify starting points. Evolution has this catch-22: Nothing evolves unless it already exists.”

Where’s the starting point?

For more than a decade, researchers have been probing the protein-origin question using molecular biology and computer models. The group led by Michael Hecht of Princeton University has made libraries of proteins that are not derived from existing proteins that have undergone millennia of Darwinian selection. Hecht and colleagues made one particular library that contained more than a million polypeptide chains composed of hydrophobic and hydrophilic residues. They demonstrated that, after being expressed in Escherichia coli, the simple polypeptides were capable of folding.

With these folded sequences, Hecht and colleagues next tested if these entities were capable of performing any biochemical function, such as binding small molecules and cofactors and catalyzing reactions. “They don’t do them well, but they do them well above background noise,” says Hecht.

After that, Hecht’s group turned to E. coli strains deleted for genes that provide essential functions for survival. The investigators transformed these strains with their peptide library and found that a couple of their polypeptides were able to rescue the E. coli and let them grow on minimal medium. “Our proteins — made from scratch and never (having) been through evolution — can provide a life-sustaining function,” Hecht says.

In silico experiments complement data from bench-based experiments. Jeffrey Skolnick and Mu Gao at the Georgia Institute of Technology designed homopolypeptides and collapsed them using a structure prediction algorithm. They then selected sequences at random that were proteinlike when matched to folds found in the Protein Data Bank. They found that each cavity in the artificial structures had a match in real proteins. Plus, there weren’t that many cavities. The cavities had the inherent capacity to bind small molecules and other ligands. “You show in a system, which was simply proteinlike but there is no selection for function, that you got a lot of properties — the binding sites, the geometries, the protein-protein interfaces. This would suggest the system fundamentally has the capacity to engage in function. Maybe it’s crummy function, but it’s still function,” says Skolnick. “This is telling you the systems are primed to do biochemistry.”
...

READ MORE HERE/LEIA MAIS AQUI: ASBM TODAY

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NOTA DESTE BLOGGER:

Mero acaso, fortuita necessidade ou 100% Design Inteligente???

Koonin ‘falou e disse’: sem uma teoria sobre a origem da vida, a biologia evolucionária está e ficará deploravelmente incompleta!

segunda-feira, outubro 14, 2013

“Contudo, a origem da vida – ou, para ser mais preciso, a origem dos primeiros sistemas replicadores e a origem da tradução – permanece um grande enigma, e progresso na solução desses problemas tem sido muito modesto – no casa de tradução, quase insignificante. Algumas observações e ideias potencialmente proveitosas existem, tais como a descoberta das plausíveis incubadoras da vida, as redes de compartimentos inorgânicos nas fontes hidrotermais, e versatilidade química das ribozimas que alimentam a hipótese do Mundo RNA. Todavia, esses avanços permanecem apenas como preliminares mesmo que importantes, porque eles nem se aproximam de um cenário de evolução pré-biológica coerente, desde as primeiras moléculas orgânicas para os primeiros sistemas replicadores, e desses para entidades biológicas bona fide nos quais o armazenamento de informação e função são partilhados entre as classes de moléculas distintas (ácidos nucléicos e proteínas, respectivamente).

Na minha opinião, apesar de todos os avanços, a biologia evolucionária está e ficará deploravelmente incompleta até que haja pelo menos um cenário de origem da vida plausível, mesmo que não seja convincente. A busca por tal solução para o derradeiro enigma pode nos levar por direções inesperadas (e profundamente absurdas para biólogos), particularmente para uma completa reavaliação dos conceitos relevantes de aleatoriedade, probabilidade, e a possível contribuição de eventos extremamente raros, como os exemplificados pela perspectiva cosmológica dados no capítulo 12.”

“However, the origin of life – or, to be more precise, the origin of the first replicator systems and the origin of translation – remains a huge enigma, and progress in solving these problems has been very modest – in the case of translation, nearly negligible. Some potentially fruitful observations and ideas exist, such as the discovery of plausible hatcheries for life, the networks of inorganic compartments at hydrothermal vents, and the chemical versatility of ribozymes that fuels the RNA World hypothesis. However, these advances remain only preliminaries, even if important ones, because they do not even come close to a coherent scenario for prebiological evolution, from the first organic molecules to the first replicator systems, and from these to bona fide biological entities in which information storage and function are partitioned between distinct classes of molecules (nucleic acids and proteins, respectively).

In my view, all advances notwithstanding, evolutionary biology is and will remain woefully incomplete until there is at least a plausible, even if not compelling, origin of life scenario. The search for such a solution to the ultimate enigma may take us in unexpected (and deeply counterintuitive for biologists) directions, particularly toward a complete reassessment of the relevant concepts of randomness, probability, and the possible contribution of extremely rare events, as exemplified by the cosmological perspective given in Chapter 12.”

Koonin, Eugene V. (2012). The Logic of Chance: The Nature and Origin of Biological Evolution, Pearson Education, Inc., Publishing as FT Press Science, New Jersey, p. 417.

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PhD Molecular Biology (1983)
Moscow State University

Phone: (301) 435-5913

Email: koonin@ncbi.nlm.nih.gov



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NOTA CAUSTICANTE DESTE BLOGGER:

Geralmente é afirmado por evolucionistas em debates que a teoria da origem da vida não é necessária para a fundamentação e corroboração da teoria da evolução de Darwin através da seleção natural e n mecanismos evolucionários de A a Z (vai que...) Quando questionados do por que dos cenários de origem da vida, segundo eles, não importante para explicar a origem e evolução biológica, aparecer nos livros didáticos de Biologia do Ensino Médio aprovados por douta comissão de pareceristas do MEC/SEMTEC/PNLEM, eles ficam em silêncio. Por que ficar em silêncio se isso não é importante???

Koonin 'falou e disse': sem uma teoria da origem da vida, a atual teoria da evolução está e ficará deploravelmente incompleta. Com a palavra os cientistas que estão elaborando a nova teoria geral da evolução - a SÍNTESE EVOLUTIVA AMPLIADA - que, pasme, somente será apresentada em 2020.

Eu aprendi na universidade que a CIÊNCIA abomina o vazio epistemológico. Então sob qual referencial teórico está sendo feita biologia evolucionária?

Finalmente Darwin ganha uma ajuda provavelmente e aproximadamente correta da matemática: eco(algo)ritmos

sábado, outubro 12, 2013

Evolution, Speeded by Computation

‘Probably Approximately Correct’ Explores Nature’s Algorithms

By EDWARD FRENKEL

Published: September 30, 2013

Our daily lives are growing ever more dependent on algorithms, those omnipresent computational procedures that run programs on our laptops, our smartphones, our GPS devices and much else. Algorithms influence our decisions, too: when we choose a movie on Netflix or a book on Amazon, we are presented with recommendations churned out by sophisticated algorithms that take into account our past choices and those of other users determined (by still other algorithms) to be similar to us.

The importance of these algorithms in the modern world is common knowledge, of course. But in his insightful new book “Probably Approximately Correct,” the Harvard computer scientist Leslie Valiant goes much further: computation, he says, is and has always been “the dominating force on earth within all its life forms.” Nature speaks in algorithms.

Dr. Valiant believes that phenomena like evolution, adaptation and learning are best understood in terms of “ecorithms,” a term he has coined for algorithms that interact with and benefit from their environment. Ecorithms are at play when children learn how to distinguish cats from dogs, when we navigate our way in a new city — but more than that, Dr. Valiant writes, when organisms evolve and when brain circuits are created and maintained.

Here is one way he illustrates this complex idea. Suppose we want to distinguish between two types of flowers by measuring their petals. For each petal we have two numbers, x for length and y for width. The task is to find a way to tell which type of flower a petal with given measurements x and y belongs to.

To achieve this, the algorithm is fed a set of examples meant to “train” it to come up with a good criterion for distinguishing the two flowers. The algorithm does not know the criterion in advance; it must “learn” it using the data that are fed to it.

So it starts with a hypothesis and tests it on the first example. (Say flower No. 1’s petals can be described by the formula 2x—3y>2, while for Flower No. 2 it’s 2x—3y<2 .="" a="" algorithm="" along.="" an="" and="" applied="" as="" by="" certain="" div="" example.="" example="" goes="" hypothesis="" if="" is="" it="" learning="" literally="" misclassifies="" new="" next="" precise="" proceed="" rule="" that="" the="" to="" updated="" we="" works="">

A striking mathematical theorem is that if a rule separating the two flowers exists (within the class of criteria we are considering, such as linear inequalities), then our algorithm will find it after a finite number of steps, no matter what the starting hypothesis was.

And Dr. Valiant argues that similar mechanisms are at work in nature. An organism can adapt to a new environment by starting with a hypothesis about the environment, then testing it against new data and, based on the feedback, gradually improving the hypothesis by using an ecorithm, to behave more effectively.

“Probably Approximately Correct,” Dr. Valiant’s winsome title, is his quantitative framework for understanding how these ecorithms work. In nature, there is nothing so neat as our idealized flower algorithm; we cannot really hope to get a precise rule distinguishing between two types of flowers, but can hope only to have one that gives an approximate result with high probability.

The evolution of species, as Darwin taught us, relies on natural selection. But Dr. Valiant argues that if all the mutations that drive evolution were simply random and equally distributed, it would proceed at an impossibly slow and inefficient pace.

Darwin’s theory “has the gaping gap that it can make no quantitative predictions as far as the number of generations needed for the evolution of a behavior of a certain complexity,” he writes. “We need to explain how evolution is possible at all, how we got from no life, or from very simple life, to life as complex as we find it on earth today. This is the BIG question.”

Dr. Valiant proposes that natural selection is supplemented by ecorithms, which enable organisms to learn and adapt more efficiently. Not all mutations are realized with equal probability; those that are more beneficial are more likely to occur. In other words, evolution is accelerated by computation.

...

O grande problema da Biologia: há muitos dados para se lidar

sexta-feira, outubro 11, 2013

Biology’s Big Problem: There’s Too Much Data to Handle



  • BY EMILY SINGER, QUANTA MAGAZINE
  • 9:30 AM



Image: Shaury Nash/Flickr


Twenty years ago, sequencing the human genome was one of the most ambitious science projects ever attempted. Today, compared to the collection of genomes of the microorganisms living in our bodies, the ocean, the soil and elsewhere, each human genome, which easily fits on a DVD, is comparatively simple. Its 3 billion DNA base pairs and about 20,000 genes seem paltry next to the roughly 100 billion bases and millions of genes that make up the microbes found in the human body.
And a host of other variables accompanies that microbial DNA, including the age and health status of the microbial host, when and where the sample was collected, and how it was collected and processed. Take the mouth, populated by hundreds of species of microbes, with as many as tens of thousands of organisms living on each tooth. Beyond the challenges of analyzing all of these, scientists need to figure out how to reliably and reproducibly characterize the environment where they collect the data.
“There are the clinical measurements that periodontists use to describe the gum pocket, chemical measurements, the composition of fluid in the pocket, immunological measures,” saidDavid Relman, a physician and microbiologist at Stanford University who studies the human microbiome. “It gets complex really fast.”
Ambitious attempts to study complex systems like the human microbiome mark biology’s arrival in the world of big data. The life sciences have long been considered a descriptive science — 10 years ago, the field was relatively data poor, and scientists could easily keep up with the data they generated. But with advances in genomics, imaging and other technologies, biologists are now generating data at crushing speeds.
One culprit is DNA sequencing, whose costs began to plunge about five years ago, falling even more quickly than the cost of computer chips. Since then, thousands of human genomes, along with those of thousands of other organisms, including plants, animals and microbes, have been deciphered. Public genome repositories, such as the one maintained by the National Center for Biotechnology Information, or NCBI, already house petabytes — millions of gigabytes — of data, and biologists around the world are churning out 15 petabases (a base is a letter of DNA) of sequence per year. If these were stored on regular DVDs, the resulting stack would be 2.2 miles tall.
“The life sciences are becoming a big data enterprise,” said Eric Green, director of the National Human Genome Research Institute in Bethesda, Md. In a short period of time, he said, biologists are finding themselves unable to extract full value from the large amounts of data becoming available.


Solving that bottleneck has enormous implications for human health and the environment. A deeper understanding of the microbial menagerie inhabiting our bodies and how those populations change with disease could provide new insight into Crohn’s disease, allergies, obesity and other disorders, and suggest new avenues for treatment. Soil microbes are a rich source of natural products like antibiotics and could play a role in developing crops that are hardier and more efficient.
Life scientists are embarking on countless other big data projects, including efforts to analyze the genomes of many cancers, to map the human brain, and to develop better biofuels and other crops. (The wheat genome is more than five times larger than the human genome, and it has six copies of every chromosome to our two.)
However, these efforts are encountering some of the same criticisms that surrounded the Human Genome Project. Some have questioned whether massive projects, which necessarily take some funding away from smaller, individual grants, are worth the trade-off. Big data efforts have almost invariably generated data that is more complicated than scientists had expected, leading some to question the wisdom of funding projects to create more data before the data that already exists is properly understood. “It’s easier to keep doing what we are doing on a larger and larger scale than to try and think critically and ask deeper questions,” said Kenneth Weiss, a biologist at Pennsylvania State University.
Compared to fields like physics, astronomy and computer science that have been dealing with the challenges of massive datasets for decades, the big data revolution in biology has also been quick, leaving little time to adapt.
“The revolution that happened in next-generation sequencing and biotechnology is unprecedented,” said Jaroslaw Zola, a computer engineer at Rutgers University in New Jersey, who specializes in computational biology.
Biologists must overcome a number of hurdles, from storing and moving data to integrating and analyzing it, which will require a substantial cultural shift. “Most people who know the disciplines don’t necessarily know how to handle big data,” Green said. If they are to make efficient use of the avalanche of data, that will have to change.
Big Complexity
When scientists first set out to sequence the human genome, the bulk of the work was carried out by a handful of large-scale sequencing centers. But the plummeting cost of genome sequencing helped democratize the field. Many labs can now afford to buy a genome sequencer, adding to the mountain of genomic information available for analysis. The distributed nature of genomic data has created its own challenges, including a patchwork of data that is difficult to aggregate and analyze. “In physics, a lot of effort is organized around a few big colliders,” said Michael Schatz, a computational biologist at Cold Spring Harbor Laboratory in New York. “In biology, there are something like 1,000 sequencing centers around the world. Some have one instrument, some have hundreds.”
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