Dawkins foi eleito o maior intelectual do mundo pela revista Prospect. Alvin Plantinga pensa o contrário...

Fonte: Logos Apologética

Darwin pensou que tinha explicado o fato, Fato, FATO da evolução: Nada mais falso!!!

Celebrando os 60 anos de DNA e os cientistas ainda não sabem como se dá o fato, Fato, FATO da evolução!!!

DNA: Celebrate the unknowns

Philip Ball

Nature 496, 419-420 (25 April 2013) doi:10.1038/496419a

Published online 24 April 2013

Neste artigo celebrando os 60 anos da dupla hélice, Philip Ball foi contundente: NÓS NÃO ENTENDEMOS TOTALMENTE COMO A EVOLUÇÃO OPERA EM NÍVEL MOLECULAR.

EXCERTO:

“Resumindo, o quadro atual de como e onde a evolução opera, e como isso modela os genomas, é algo bagunçado... Raramente um sussurro deste debate vibrante chega ao público. Tome por exemplo a descrição do biólogo evolucionista Richard Dawkins feita ano passado na revista Prospect sobre o gene como um replicador com ‘seu status exclusivo de uma unidade de seleção darwiniana’. Isso evoca o quadro há décadas de um pequeno trecho de intenção autônoma do DNA em copiar a si mesmo, sem nenhuma indicação de que a seleção opera em todos os níveis de hierarquia biológica, inclusive o nível 2 supra-organismal, ou que a própria ideia de 'gene' se tornou problemática.

“In short, the current picture of how and where evolution operates, and how this shapes genomes, is something of a mess... Barely a whisper of this vibrant debate reaches the public. Take evolutionary biologist Richard Dawkins' description in Prospect magazine last year of the gene as a replicator with "its own unique status as a unit of Darwinian selection". It conjures up the decades-old picture of a little, autonomous stretch of DNA intent on getting itself copied, with no hint that selection operates at all levels of the biological hierarchy, including at the supraorganismal level 2, or that the very idea of 'gene' has become problematic.

Por que esta relutância aparente de reconhecer a complexidade? Um obstáculo pode ser o sentimentalismo. A biologia é tão complicada que pode ser profundamente penoso para alguns ter que abandonar a promessa de um mecanismo elegante fundamental.

Em cosmologia, um só fato destruidor (a expansão acelerada do universo) reescreveu prontamente a narrativa. Mas em evolução molecular, os argumentos antigos, por exemplo, sobre a importância da seleção natural e a deriva genética na condução da mudança genética, estão colidindo agora com questões sobre o RNA não-codificantes, epigenética e a teoria da rede genômica. Ainda não está claro qual nova história a se contar.”

Why this apparent reluctance to acknowledge the complexity? One roadblock may be sentimentality. Biology is so complicated that it may be deeply painful for some to relinquish the promise of an elegant core mechanism.

In cosmology, a single, shattering fact (the Universe's accelerating expansion) cleanly rewrote the narrative. But in molecular evolution, old arguments, for instance about the importance of natural selection and random drift in driving genetic change, are now colliding with questions about non-coding RNA, epigenetics and genomic network theory. It is not yet clear which new story to tell.”

Nature

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Professores, pesquisadores e alunos de universidades públicas e privadas com acesso ao site Capes/Periódicos podem ler gratuitamente este artigo da Nature e de mais 22.440 publicações científicas.

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NOTA SARCÁSTICA DESTE BLOGGER:

Philip Ball, sem querer, querendo, jogou de vez na lata do lixo da História da Ciência que a teoria da evolução é uma teoria científica tão corroborada como a lei da gravidade e assim como a Terra gira em torno do Sol. Gente, queria ver a cara de alguns cientistas da Nomenklatura científica e a Galera dos meninos e meninas de Darwin que a cada dia mais ficam sem pai nem mãe, oops sem contra-argumentos.

E a nova teoria geral da evolução - a SÍNTESE EVOLUTIVA AMPLIADA (ESTENDIDA) que somente será anunciada em 2020??? Como está sendo feito biologia evolucionária se a ciência ABOMINA o vácuo epistêmico???

Pano rápido:  

OS CIENTISTAS NÃO ENTENDEM TOTALMENTE COMO A EVOLUÇÃO OPERA EM NÍVEL MOLECULAR.

A descoberta do DNA fez 60 anos

JC e-mail 4713, de 25 de Abril de 2013.

4. Descoberta da dupla hélice faz 60 anos, genoma humano, 10

O sequenciamento do genoma humano não teria sido possível sem a elucidação da estrutura molecular do DNA

Dois grandes feitos da ciência fazem aniversário neste mês. Cerca de duas semanas atrás, comemoraram-se dez anos do primeiro sequenciamento completo de um genoma humano, anunciado em 14 de abril de 2003 por um consórcio internacional de cientistas. Esse marco científico e tecnológico que está revolucionando a medicina, porém, jamais teria sido possível sem um outro feito monumental, que completa 60 anos na quinta-feira (25): a elucidação da estrutura molecular do DNA.

Source: BBC

A descoberta da dupla hélice pelo americano James Watson e o britânico Francis Crick estabeleceu a pedra fundamental sobre a qual todo o conhecimento moderno da genética humana e da evolução da vida na Terra está estruturado.

Sem conhecer a estrutura da molécula de DNA, seria impossível entender como funciona. E, sem entender como o DNA funciona, seria impossível entender como a vida funciona. A existência do DNA (ácido desoxirribonucleico) já era conhecida desde o fim do século 19, mas sua estrutura molecular (e portanto suas funções essenciais) permaneceu um mistério até Watson e Crick a desvendarem. O trabalho histórico, curto e elegantemente simples com apenas uma página e um desenho, foi publicado em 25 de abril de 1953 na revista científica britânica Nature.

"Foi um trabalho tão bem feito que até hoje está do jeito que está, sem nenhuma correção, e continua a ser uma fonte básica de informação para livros-texto de várias disciplinas", diz o pesquisador Eduardo Gorab, do Departamento de Genética do Instituto de Biociências da Universidade de São Paulo. "De longe foi o trabalho que deixou todos os outros para trás", completa, referindo-se à corrida que havia na comunidade científica da época para chegar à cobiçada estrutura.

[NOTA E GENTILEZA DESTE BLOGGER: 

O trabalho de Crick e Watson pode ser baixado gratuitamente aqui As pesquisas de Rosalind Franklin foram sub-repticiamente retiradas de seu laboratório e chegaram às mãos de Crick e Watson. 

Em que pese o valor histórico, o trabalho de Crick e Watson continha um erro:

Eles afirmaram que cada par de base (par de purina-pirimidina, A-T e C-G, era mantido unido por duas ligações de hidrogênio. Sabemos hoje que, embora isso seja verdade para a adenina-timina (A-T), o par de citosina-guanina (C-G) envolve três ligações de hidrogênio.]

Nove anos depois da publicação da descoberta, Watson e Crick receberam o Prêmio Nobel pela descoberta, ao lado do britânico Maurice Wilkins, que elucidou algumas das funções biológicas associadas à estrutura da dupla hélice. Os três pesquisadores foram originalmente nomeados para receber o Nobel de Química, mas acabaram recebendo o de Medicina, pelo reconhecimento - então pioneiro - das enormes implicações da descoberta para a compreensão da biologia humana.

[PERGUNTA SARCÁSTICA DO BLOGGER: Por que não receberam o Nobel de Biologia Evolucionária???]

IMPLICAÇÕES - Meio século mais tarde, a descoberta da dupla hélice desembocou no sequenciamento do genoma humano, que por sua vez desencadeou um processo de revolução científica e tecnológica na Medicina como um todo. Quase todas as doenças humanas têm um componente genético. Ou são causadas diretamente ou, no mínimo, são influenciadas (para o bem ou para o mal) por características genéticas individuais de cada paciente. Conhecer e entender essas características, portanto, é um dos objetivos mais importantes da medicina moderna. A chamada "medicina personalizada"."É algo que vai ter repercussões tremendas nos próximos anos", diz o pesquisador Emmanuel Dias Neto, do Centro Internacional de Pesquisa e Ensino do Hospital A. C. Camargo.

A tecnologia para isso avança numa velocidade espantosa. O sequenciamento e o mapeamento do primeiro genoma humano custaram quase US$ 3 bilhões e levou mais de dez anos para ser concluído. Hoje, pode-se sequenciar um genoma humano em um dia, por cerca de US$ 1 mil, numa única máquina. São comuns projetos de pesquisa envolvendo o sequenciamento de milhares de pacientes. "Quanto mais informações temos, mais coisas podemos fazer com elas", diz Emmanuel, que trabalha com genética de câncer. "A tecnologia hoje nos permite fazer coisas que jamais imaginaríamos possíveis."

(Herton Escobar / O Estado de São Paulo)

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NOTA DO BLOGGER:

A revista Nature tem um artigo sobre os 60 anos do DNA com afirmações e perguntas interessantes sobre o status do fato, Fato, FATO da evolução  revelado nesta "pedra fundamental sobre a qual todo o conhecimento moderno da genética humana e da evolução da vida na Terra está estruturado". Excertos neste blog em postagem distinta.

I Encontro Nacional de Fé e Ciência para o Século XXI na Universidade Presbiteriana Mackenzie - 14-15 de maio de 2013

INSCRIÇÕES: 

http://www.mackenzie.com.br

Relógio Omega co-axial, uma obra prima do mero acaso, fortuita necessidade ou design inteligente???

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NOTA DESTE BLOGGER:

A Nomenklatura científica afirma e bate com os pés juntos que os sinais de  design vistos na natureza são meras ilusões, especialmente nas máquinas biológicas obras primas de nanotecnologia avançada. E pontificam que a teoria do Design Inteligente é criacionismo disfarçado, pseudociência y otras cositas mais...

A propaganda do relógio Omega acima atesta que esta obra prima é fruto de design inteligente e não de mero acaso ou fortuita necessidade. Acho que por detrás dessa resistência à TDI o que existe mesmo é uma ideologia materialista que posa como se fosse ciência. Nada mais falso!!!

Papéis da mutação e seleção na especiação: de Hugo de Vries à era genômica moderna

Roles of Mutation and Selection in Speciation: From Hugo de Vries to the Modern Genomic Era

Masatoshi Nei* and Masafumi Nozawa

- Author Affiliations

Institute of Molecular Evolutionary Genetics and Department of Biology, Pennsylvania State University

↵*Corresponding author: E-mail: nxm2@psu.edu.

Accepted March 17, 2011.

Abstract

One of the most important problems in evolutionary biology is to understand how new species are generated in nature. In the past, it was difficult to study this problem because our lifetime is too short to observe the entire process of speciation. In recent years, however, molecular and genomic techniques have been developed for identifying and studying the genes involved in speciation. Using these techniques, many investigators have already obtained new findings. At present, however, the results obtained are complex and quite confusing. We have therefore attempted to understand these findings coherently with a historical perspective and clarify the roles of mutation and natural selection in speciation. We have first indicated that the root of the currently burgeoning field of plant genomics goes back to Hugo de Vries, who proposed the mutation theory of evolution more than a century ago and that he unknowingly found the importance of polyploidy and chromosomal rearrangements in plant speciation. We have then shown that the currently popular Dobzhansky–Muller model of evolution of reproductive isolation is only one of many possible mechanisms. Some of them are Oka’s model of duplicate gene mutations, multiallelic speciation, mutation-rescue model, segregation-distorter gene model, heterochromatin-associated speciation, single-locus model, etc. The occurrence of speciation also depends on the reproductive system, population size, bottleneck effects, and environmental factors, such as temperature and day length. Some authors emphasized the importance of natural selection to speed up speciation, but mutation is crucial in speciation because reproductive barriers cannot be generated without mutations.

Key words

chromosomal mutation Dobzhansky–Muller model hybrid sterility hybrid inviability Oka model polyploidy

© The Author(s) 2011. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

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Vamos rever o processo de revisão por pares

Let's review the peer review process

18 APRIL 2013

SOURCE: JAMES FRYER

We must hold up a mirror to scientific peer review if we are to stamp out fraud and uphold the discipline’s reputation, argues Philip Moriarty

The website Science-fraud.org was established in July 2012 by the pseudonymous Frances de Triusce (an anagram of “science fraudster”) with the aim of highlighting suspicious papers in the scientific literature. Barely six months later, having brought to light around 500 examples of what might best be called questionable data, and with a daily readership in the thousands, the website was shut down.

Its founder’s true identity had been uncovered - he was Paul Brookes, an associate professor at the University of Rochester Medical Center in the US - and an email had been sent to around 85 scientists whose data had been questioned on the site, encouraging them to sue him for defamation. The email, which described Science-fraud.org as a “hate site” and, rather ironically, as a menace to “scientific society”, was also copied to Brookes’ superiors at Rochester (including its president), the editors of journals in which he had published and prominent people in his field who might be expected to be involved in peer reviewing his grants and papers.

Brookes’ immense frustration with both this deplorable act and the current state of scientific peer review was clear in his final post on the Science Fraud site: “As I have learned the hard way, anyone who dares to stick their neck on the line and question the data of their peers is ostracised, stone walled and subjected to lawsuits.” He went on to argue that the way forward would be to assemble what he called a “coalition of the willing” - to be known as the Association for Anonymous Post-Publication Peer Review - to effectively police the literature, flagging up questionable data and papers. A Science Fraud 2.0, in other words, albeit with a less incendiary name.

I have an immense amount of respect for Brookes, and for all those who will join his coalition. His integrity and commitment to science is laudable and inspiring. But why should he have to stick his neck on the line again? Do we really have to rely on what amounts to academic vigilantism to preserve the integrity of the scientific record? And who decides what constitutes a breach of scientific integrity in any case?

This latter question is, perhaps surprisingly, rather vexed. Even in cases of straightforward fraud - the manipulation, modification, and/or direct fabrication of data - establishing beyond doubt the guilt of the authors is rarely straightforward. But at least journal editors’ responsibility in these circumstances is clear: the paper must be retracted.

A study by medical communications consultant R. Grant Steen of papers retracted from the PubMed database between 2000 and 2010, which was published in the Journal of Medical Ethics in 2010, found that retractions had increased from fewer than 10 in 2000 to close to 180 in 2010. Even more worryingly, in nearly a third of cases journals did not even highlight (via, for example, a watermark on the article) that the paper had been retracted. However, only 27 per cent of the retractions were because of fraud; the rest were attributable either to “undisclosed” reasons or what appears to be genuine scientific error.

But exactly what constitutes scientific error? Should a paper be retracted when there are clear flaws in its methodology? Or when its interpretations are unsupported by the data? Or even when subsequent experiments show its conclusions are incorrect - even if the experimental and theoretical work were carried out to a very high standard? The last suggestion was supported in a widely publicised and very controversial blog posting last year by PLOS Medicine chief editor Virginia Barbour and PLOS Pathogens editor-in-chief Kasturi Haldar. They wrote: “We work with authors…to publish corrections if we find parts of articles to be inaccurate. If a paper’s major conclusions are shown to be wrong we will retract the paper. By doing so, and by being open about our motives, we hope to clarify once and for all that there is no shame in correcting the literature. Despite the best of efforts, errors occur and their timely and effective remedy should be considered the mark of responsible authors, editors and publishers.”

There is much that is laudable in this statement. The journal PLOS One, in particular, has an admirable track record of providing a forum for post- publication critiquing of its articles, and it should also be noted that Barbour is chair of the Committee on Publication Ethics, whose guidelines should be - but currently aren’t - embedded in the codes of practice of all scientific publishers. Yet the suggestion that a paper should be retracted if its conclusions are wrong is a step much too far, and would be baulked at by the majority of scientists.

If a paper’s data are reliable, its methodologies sound and its conclusions plausible at the time and based on the data (rather than authors’ wishful thinking), it is broadly valid and should remain part of the scientific record.

But what if the data and methods aren’t reliable? What if, for example, the researchers are unaware of experimental artefacts that provide a more plausible explanation of their data than the more novel and exciting interpretation they have advanced? Some might argue that the primary responsibility for identifying this type of problem lies with peer reviewers, but, as Richard Feynman said in his 1974 commencement address at the California Institute of Technology, scientists need to go the extra mile in self-criticism before they submit their work for publication.

“If you’re doing an experiment, you should report everything that you think might make it invalid - not only what you think is right about it…The first principle is that you must not fool yourself - and you are the easiest person to fool…After you’ve not fooled yourself, it’s easy not to fool [others],” he said.

It should be said that Feynman’s advice is not entirely consistent with a culture where scientists’ primary goal can too often be to ensure that the paper “gets past the referees”. Nevertheless, it remains received wisdom that science proceeds via a process of self-correction, such that errors will, eventually, be exposed. As comforting a picture as this is, the evidence is stacking up against it.

...

Read more here/Leia mais aqui: The Times Higher Education

Sequência do genoma referência do peixe paulistinha e a sua relação com o genoma humano

The zebrafish reference genome sequence and its relationship to the human genome
Kerstin Howe, Matthew D. Clark, Carlos F. Torroja, James Torrance, Camille Berthelot, Matthieu Muffato, John E. Collins, Sean Humphray, Karen McLaren, Lucy Matthews, Stuart McLaren, Ian Sealy, Mario Caccamo, Carol Churcher, Carol Scott, Jeffrey C. Barrett, Romke Koch, Gerd-Jörg Rauch, Simon White, William Chow, Britt Kilian, Leonor T. Quintais, José A. Guerra-Assunção, Yi Zhou, Yong Gu et al.

Affiliations Contributions Corresponding author

Nature (2013) doi:10.1038/nature12111

Received 23 August 2012 Accepted 21 March 2013 Published online 17 April 2013

Abstract

Zebrafish have become a popular organism for the study of vertebrate gene function1, 2. The virtually transparent embryos of this species, and the ability to accelerate genetic studies by gene knockdown or overexpression, have led to the widespread use of zebrafish in the detailed investigation of vertebrate gene function and increasingly, the study of human genetic disease3, 4, 5. However, for effective modelling of human genetic disease it is important to understand the extent to which zebrafish genes and gene structures are related to orthologous human genes. To examine this, we generated a high-quality sequence assembly of the zebrafish genome, made up of an overlapping set of completely sequenced large-insert clones that were ordered and oriented using a high-resolution high-density meiotic map. Detailed automatic and manual annotation provides evidence of more than 26,000 protein-coding genes6, the largest gene set of any vertebrate so far sequenced. Comparison to the human reference genome shows that approximately 70% of human genes have at least one obvious zebrafish orthologue. In addition, the high quality of this genome assembly provides a clearer understanding of key genomic features such as a unique repeat content, a scarcity of pseudogenes, an enrichment of zebrafish-specific genes on chromosome 4 and chromosomal regions that influence sex determination.

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O genoma do celacanto africano fornece insights na evolução dos tetrápodes

The African coelacanth genome provides insights into tetrapod evolution

Chris T. Amemiya, Jessica Alföldi, Alison P. Lee, Shaohua Fan, Hervé Philippe, Iain MacCallum, Ingo Braasch, Tereza Manousaki, Igor Schneider, Nicolas Rohner, Chris Organ, Domitille Chalopin, Jeramiah J. Smith, Mark Robinson, Rosemary A. Dorrington, Marco Gerdol, Bronwen Aken, Maria Assunta Biscotti, Marco Barucca, Denis Baurain, Aaron M. Berlin, Gregory L. Blatch, Francesco Buonocore, Thorsten Burmester, Michael S. Campbell et al.

Affiliations Contributions Corresponding authors

Nature 496, 311–316 (18 April 2013) doi:10.1038/nature12027

Received 05 September 2012 Accepted 20 February 2013 Published online 17 April 2013

Abstract

The discovery of a living coelacanth specimen in 1938 was remarkable, as this lineage of lobe-finned fish was thought to have become extinct 70 million years ago. The modern coelacanth looks remarkably similar to many of its ancient relatives, and its evolutionary proximity to our own fish ancestors provides a glimpse of the fish that first walked on land. Here we report the genome sequence of the African coelacanth, Latimeria chalumnae. Through a phylogenomic analysis, we conclude that the lungfish, and not the coelacanth, is the closest living relative of tetrapods. Coelacanth protein-coding genes are significantly more slowly evolving than those of tetrapods, unlike other genomic features. Analyses of changes in genes and regulatory elements during the vertebrate adaptation to land highlight genes involved in immunity, nitrogen excretion and the development of fins, tail, ear, eye, brain and olfaction. Functional assays of enhancers involved in the fin-to-limb transition and in the emergence of extra-embryonic tissues show the importance of the coelacanth genome as a blueprint for understanding tetrapod evolution.

Subject terms: Genome evolution Comparative genomics

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Um caso moral contra o darwinismo

Douglas Groothuis, Ph.D.

Um argumento moral contra o darwinismo

1. Se o darwinismo for uma descrição adequada da bioesfera, então os seres humanos não têm nenhuma natureza essencial, uma vez que eles evoluíram sem design intencional até às suas formas atuais.

2. Se (1), então as várias raças de humanos podem ser mais evoluídas (isto é, adaptavelmente mais bem sucedidas) do que as outras raças. Darwin mesmo afirmou isso no seu livro The Descent of Man.

3. Se (2), não existe nada intrinsecamente valioso sobre a raça humana como um todo. Isto é, algumas raças podem prevalecer sobre outras raças devido às suas vantagens seletivas devido à sua trajetória evolucionária exclusiva.

4. Se (3), então não existe nenhuma base filosófica para a afirmação de que os seres humanos qua seres humanos têm direitos humanos objetivos e universais.

5. Mas (4) é falso. As nossas intuições morais e a história da lei ocidental tratam a cada ser humano, sem distinção de raça, como possuindo dignidade humana intrínseca e deve ser tratado como tal. A Declaração dos Direitos Humanos das Nações Unidas afirmam isso, por exemplo, como faz a Declaração de Independência dos Estados Unidos – “Todos os homens são criados iguais”.

6. Além disso, se (4) for verdadeiro, então nós não temos nenhuma base objetiva para condenar moralmente a escravidão ou até mesmo a eliminação das “raças menos favorecidas” (termo usado por Darwin).

7. Mas (4) é falso, por causa de (5).

8. Portanto (6) é falso por causa de (5).

9. Portanto, (1)— o darwinismo — é falso. Isso por meio do modus tollens que, neste caso, é um reductio ad absurdum (reduzir a afirmação ao absurdo).

Nota: modus tollens (ou negar o consequente):

a. Se P, então Q.

b. Não Q.

c. Portanto, não P.

Postado por Douglas Groothuis, Ph. D. 10:16 PM

Judith Curry ‘falou e disse’: estratégias para lidar com os céticos

Judith Curry ‘falou e disse’ que existem três estratégias para lidar com os céticos e críticos (do aquecimento global ser antropogenicamente provocado):

1. Refugiar-se na torre de marfim.

2. Proteger-se/apontar as armas para fora: ataques ad hominem/apelo para motivar ataques; apelo para autoridade; isolar o inimigo através da falta de acesso aos dados; processo de revisão por pares.

3. Tomar a posição de “superioridade”: lidar com os céticos em nossos termos (conferências, blogosfera); tornar os dados/métodos disponíveis/transparentes; esclarecer as incertezas; declarar abertamente os nossos valores.

Fonte

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NOTA DESTE BLOGGER:

Parece que esta tem sido a estratégia adotada pela Nomenklatura científica quando a batata epistêmica fica quente no contexto de justificação teórica e os críticos e céticos apontam que determinadas teorias científicas queridinhas não são assim nenhuma Brastemp, e que é melhor tomar a atitude acima em vez de lidar publicamente com a falência epistemológica dessas teorias.

Deve ser por isso que a Nomenklatura científica tupiniquim não dá nenhum pio  sobre a falência fragorosa da teoria da evolução de Darwin através da seleção natural e n mecanismos evolucionários desde que os teóricos e proponentes da teoria do Design Inteligente disseram e apontaram que Darwin está nu e não fecha as contas heurísticas evolucionárias desde 1859.

Pior é a Grande Mídia. Sabe de tudo isso, mas nada publica porque vive uma relação incestuosa com a Nomenklatura científica. Que vergonha! É que falta cojones na Grande Mídia quando a questão é Darwin...

A vida antes da Terra ainda continua um grande Mysterium tremendum!!!

Life Before Earth

Alexei A. Sharov, Richard Gordon

(Submitted on 28 Mar 2013)

An extrapolation of the genetic complexity of organisms to earlier times suggests that life began before the Earth was formed. Life may have started from systems with single heritable elements that are functionally equivalent to a nucleotide. The genetic complexity, roughly measured by the number of non-redundant functional nucleotides, is expected to have grown exponentially due to several positive feedback factors: gene cooperation, duplication of genes with their subsequent specialization, and emergence of novel functional niches associated with existing genes. Linear regression of genetic complexity on a log scale extrapolated back to just one base pair suggests the time of the origin of life 9.7 billion years ago. This cosmic time scale for the evolution of life has important consequences: life took ca. 5 billion years to reach the complexity of bacteria; the environments in which life originated and evolved to the prokaryote stage may have been quite different from those envisaged on Earth; there was no intelligent life in our universe prior to the origin of Earth, thus Earth could not have been deliberately seeded with life by intelligent aliens; Earth was seeded by panspermia; experimental replication of the origin of life from scratch may have to emulate many cumulative rare events; and the Drake equation for guesstimating the number of civilizations in the universe is likely wrong, as intelligent life has just begun appearing in our universe. Evolution of advanced organisms has accelerated via development of additional information-processing systems: epigenetic memory, primitive mind, multicellular brain, language, books, computers, and Internet. As a result the doubling time of complexity has reached ca. 20 years. Finally, we discuss the issue of the predicted technological singularity and give a biosemiotics perspective on the increase of complexity.

Comments: 26 pages, 3 figures

Subjects: General Physics (physics.gen-ph)

Cite as: arXiv:1304.3381 [physics.gen-ph]

  (or arXiv:1304.3381v1 [physics.gen-ph] for this version)

Submission history

From: Alexei Sharov [view email] 

[v1] Thu, 28 Mar 2013 17:00:11 GMT (287kb)

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Reproduzir novamente a fita da vida: a quantificação da previsibilidade da evolução

Front Genet. 2012; 3: 246.

Published online 2012 November 26. Prepublished online 2012 August 31. doi:  10.3389/fgene.2012.00246

PMCID: PMC3509945

Replaying the Tape of Life: Quantification of the Predictability of Evolution

Abstract

The question whether adaptation follows a deterministic route largely prescribed by the environment or can proceed along a large number of alternative trajectories has engaged extensive research over the recent years. Experimental evolution studies enabled by advances in high throughput techniques for genome sequencing and manipulation, along with increasingly detailed mathematical modeling of fitness landscapes, are beginning to allow quantitative exploration of the repeatability of evolutionary trajectories. It is becoming clear that evolutionary trajectories in static correlated fitness landscapes are substantially non-random but the relative contributions of determinism and stochasticity in the evolution of specific phenotypes strongly depend on the specific conditions, particularly the magnitude of the selective pressure and the number of available beneficial mutations.

Keywords: evolutionary trajectory, predictability of evolution, fitness landscape, divergence of trajectories

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Ensinar ciência através da discussão de evidências disponíveis

Learning to argue: A study of four schools and their attempt to develop the use of argumentation as a common instructional practice and its impact on students

Jonathan Osborne1,*, Shirley Simon2, Andri Christodoulou3, Christina Howell-Richardson4, Katherine Richardson2

Article first published online: 17 JAN 2013

DOI: 10.1002/tea.21073

Journal of Research in Science Teaching

Volume 50, Issue 3, pages 315–347, March 2013

Dr. Jonathan Osborne - Credit: Linda A. Cicero

Keywords:

teacher professional development; argumentation; dialogic teaching; student engagement; epistemic learning

Abstract

This article reports the outcomes of a project in which teachers' sought to develop their ability to use instructional practices associated with argumentation in the teaching of science—in particular, the use of more dialogic approach based on small group work and the consideration of ideas, evidence, and argument. The project worked with four secondary school science departments over 2 years with the aim of developing a more dialogic approach to the teaching of science as a common instructional practice within the school. To achieve this goal, two lead teachers in each school worked to improve the use of argumentation as an instructional practice by embedding activities in the school science curriculum and to develop their colleague's expertise across the curriculum for 11- to 16-year-old students. This research sought to identify: (a) whether such an approach using minimal support and professional development could lead to measurable difference in student outcomes, and (b) what changes in teachers' practice were achieved (reported elsewhere). To assess the effects on student learning and engagement, data were collected of students' conceptual understanding, reasoning, and attitudes toward science from both the experimental schools and a comparison sample using a set of standard instruments. Results show that few significant changes were found in students compared to the comparison sample. In this article, we report the findings and discuss what we argue are salient implications for teacher professional development and teacher learning. © 2013 Wiley Periodicals, Inc. J Res Sci Teach 50:315–347, 2013

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Journal of Research in Science Teaching

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NOTA DESTE BLOGGER:

Queria ver o ensino de ciências através da discussão de evidências aqui no Brasil. Muitas teorias científicas, especialmente as das origens e evolução do universo e da vida seriam ensinadas menos dogmaticamente como têm sido até agora! Os alunos ficariam, finalmente, sabendo que elas não são assim uma Brastemp no contexto de justificação teórica, e que se discute internamente entre os cientistas o alcance epistêmicos delas.

Que venga la nueva teoría de la evolución!!! 

Não é improdutivo discutir sobre o Design Inteligente, improdutivo é discutir com Silvia Regina Gobbo, uma darwinista fundamentalista xiita

Fiz um comentário na página do Dr. Marcos Eberlin, no Facebook, e troquei ideias com a Silvia Regina Gobbo. Uma perda de tempo, pois ela muda de assunto como macaco pula de galho em galho. Além de ser destemperada e agressiva.

Como educadamente saí da conversa dizendo que iria fazer coisa mais produtiva para a humanidade - trabalhar, ela me ameaçou infantilmente que tinha printado nossa conversa e ia postar que eu tinha dito não valer a pena discutir sobre a Teoria do Design Inteligente! Posto aqui, esclarecendo o por que da minha perda de tempo: ela não reconhece a falência da teoria da evolução de Darwin através da seleção natural e n mecanismos evolucionários.

Células têm bússolas que as conduzem até aos ferimentos. Darwin ou Design Inteligente explica melhor isso?

Keratocyte Fragments and Cells Utilize Competing Pathways to Move in Opposite Directions in an Electric Field

Current Biology, Volume 23, Issue 7, 569-574, 28 March 2013

Copyright © 2013 Elsevier Ltd All rights reserved.

10.1016/j.cub.2013.02.026

Authors

Yaohui Sun, Hao Do, Jing Gao, Ren Zhao, Min Zhao, Alex MogilnerSee 

Affiliations

Highlights

A cell fragment is the simplest motile electric-field-sensing unit

Keratocyte cells and fragments migrate in opposite directions in an electric field

Competition of two signal transduction pathways underlies keratocyte galvanotaxis

Protrusive and contractile actin networks are steered by the electric field

Summary

Sensing of an electric field (EF) by cells—galvanotaxis—is important in wound healing [1], development [2], cell division, nerve growth, and angiogenesis [3]. Different cell types migrate in opposite directions in EFs [4], and the same cell can switch the directionality depending on conditions [5]. A tug-of-war mechanism between multiple signaling pathways [6] can direct Dictyostelium cells to either cathode or anode. Mechanics of motility is simplest in fish keratocytes, so we turned to keratocytes to investigate their migration in EFs. Keratocytes sense electric fields and migrate to the cathode [7,8]. Keratocyte fragments [9,10] are the simplest motile units. Cell fragments from leukocytes are able to respond to chemotactic signals [11], but whether cell fragments are galvanotactic was unknown. We found that keratocyte fragments are the smallest motile electric field-sensing unit: they migrate to the anode, in the opposite direction of whole cells. Myosin II was essential for the direction sensing of fragments but not for parental cells, while PI3 kinase was essential for the direction sensing of whole cells but not for fragments. Thus, two signal transduction pathways, one depending on PI3K, another on myosin, compete to orient motile cells in the electric field. Galvanotaxis is not due to EF force and does not depend on cell or fragment size. We propose a “compass” model according to which protrusive and contractile actomyosin networks self-polarize to the front and rear of the motile cell, respectively, and the electric signal orients both networks toward cathode with different strengths.

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Current Biology

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PERGUNTA DESTE BLOGGER:

Darwin ou Design Inteligente explicar melhor essa questão teleológica? Afinal de contas, as células dispõe de 'bússolas' que as 'orientam' até aos ferimentos???

Radiações múltiplas de girinos camarões desafiam o conceito de 'fósseis vivos'

Multiple global radiations in tadpole shrimps challenge the concept of ‘living fossils’

Thomas C. Mathers1, Robert L. Hammond2, Ronald A. Jenner3, Bernd Hänfling1, Africa Gómez 1

Author and article information

1 School of Biological, Biomedical and Environmental Sciences, University of Hull, Hull, UK

2 Department of Biology, University of Leicester, Leicester, UK

3 Life Sciences Department, The Natural History Museum, London, UK

DOI 10.7717/peerj.62

Triops cancriformis, the European Tadpole Shrimp. Credit: Africa Gomez

Abstract

‘Living fossils’, a phrase first coined by Darwin, are defined as species with limited recent diversification and high morphological stasis over long periods of evolutionary time. Morphological stasis, however, can potentially lead to diversification rates being underestimated. Notostraca, or tadpole shrimps, is an ancient, globally distributed order of branchiopod crustaceans regarded as ‘living fossils’ because their rich fossil record dates back to the early Devonian and their morphology is highly conserved. Recent phylogenetic reconstructions have shown a strong biogeographic signal, suggesting diversification due to continental breakup, and widespread cryptic speciation. However, morphological conservatism makes it difficult to place fossil taxa in a phylogenetic context. Here we reveal for the first time the timing and tempo of tadpole shrimp diversification by inferring a robust multilocus phylogeny of Branchiopoda and applying Bayesian divergence dating techniques using reliable fossil calibrations external to Notostraca. Our results suggest at least two bouts of global radiation in Notostraca, one of them recent, so questioning the validity of the ‘living fossils’ concept in groups where cryptic speciation is widespread.

Cite this as

Mathers et al. (2013) Multiple global radiations in tadpole shrimps challenge the concept of ‘living fossils’. PeerJ 1:e62 http://dx.doi.org/10.7717/peerj.62

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Dineína axonemal - um motor molecular natural via Darwin ou Design Inteligente?

Axonemal dynein - a natural molecular motor

by Helen C. Taylor* and Michael E.J. Holwill

Physics Department, King's College London, Strand, London WC2R 2LS, UK 

*Corresponding author: hct@wallace.ph.kcl.ac.uk

This is a draft paper for the Sixth Foresight Conference on Molecular Nanotechnology. 

The final version has been submitted for publication in the special Conference issue of Nanotechnology.

The axoneme (Fig. 1) is the core structure of a cilium or flagellum, and consists of a set of nine doublet microtubules -- each of which consists of a partial microtubule connected to a complete microtubule -- arranged cylindrically around a pair of singlet microtubules. These microtubules are arranged with their plus ends at the tip of the axoneme and their minus ends anchored in basal bodies in the cell. The axonemal dynein motors are distributed along each doublet as inner and outer rows of arms (Fig. 1).

Summary

Biological motor molecules in vivo possess many of the characteristics required to power nanomachines. They can generate force and torque, transport specific cargoes over appropriate substrates, and the character and rate of their action can be controlled. In cilia and flagella, axonemal dynein motor molecules are attached to nine microtubule doublets arranged cylindrically around a pair of single microtubules. The dynein motors undergo a cycle of activity, during which they form a transient attachment to the doublet, and push it towards the tip of the cilium or flagellum. The microscopy techniques currently available do not have sufficient resolving power to view this activity directly. Instead, movement of microtubules by the action of assemblies of isolated dynein arms activated by ATP can be studied in vitro. At a particular ATP concentration, microtubule gliding velocities are found to increase with microtubule length. By making appropriate assumptions about the system, it is possible to predict its behaviour using computer simulations. These simulations allow us to investigate certain properties of individual dynein molecules in addition to characterising the co-ordination of activity within the assembly of arms. Agreement between the experimental results and computer predictions can be achieved by selecting appropriate characteristics of individual dynein arm action for either random or systematic activity of the arm assembly. Based on our computer simulations, it is possible to design experiments to differentiate between the co-ordination patterns. We have also simulated microtubule sliding for comparison with the sliding which occurs when microtubules are extruded from disintegrating cilia and flagella. These studies lay the foundation for the development of computer models of the whole axoneme, which will allow us to investigate the way in which the dynein motors interact with other structures to produce ciliary and flagellar bending.

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