Compilado AZyNE 25-11

Lynn Margulis 1938-2011 "Gaia Is A Tough Bitch", Edge.org

Excerpt: Biologist Lynn Margulis died on November 22nd. She stood out from her colleagues in that she would have extended evolutionary studies nearly four billion years back in time. Her major work was in cell evolution, in which the great event was the appearance of the eukaryotic, or nucleated, cell �" the cell upon which all larger life-forms are based. Nearly forty-five years ago, she argued for its symbiotic origin: that it arose by associations of different kinds of bacteria. Her ideas were generally either ignored or ridiculed when she first proposed them; symbiosis in cell evolution is now considered one of the great scientific breakthroughs.

• Source: Lynn Margulis 1938-2011 "Gaia Is A Tough Bitch", John Brockman, Edge.org, 2011/11/23

The role of sex separation in neutral speciation, arXiv

Abstract: Neutral speciation mechanisms based on isolation by distance and sexual selection, termed topopatric, have recently been shown to describe the observed patterns of abundance distributions and species-area relationships. Previous works have considered this type of process only in the context of hermaphrodic populations. In this work we extend a hermaphroditic model of topopatric speciation to populations where individuals are explicitly separated into males and females. We show that for a particular carrying capacity speciation occurs under similar conditions, but the number of species generated decreases as compared to the hermaphroditic case. Evolution results in fewer species having more abundant populations.

• Source: The role of sex separation in neutral speciation, Elizabeth M. Baptestini, Marcus A.M. de Aguiar, Yaneer Bar-Yam, arXiv:1111.4643, 2011/11/20

Evolutionary Time Travel, Science

Summary: With clever and challenging lab experiments, researchers are forcing species to become multicellular, develop new energy sources, and start having sex.

• Source: Evolutionary Time Travel, Elizabeth Pennisi, DOI: 10.1126/science.334.6058.893, Science Vol. 334 no. 6058 pp. 893-895, 2011/11/18

Compilado AZyNE 12-11

Social Network Size Affects Neural Circuits in Macaques, Science

Abstract: It has been suggested that variation in brain structure correlates with the sizes of individuals’ social networks. Whether variation in social network size causes variation in brain structure, however, is unknown. To address this question, we neuroimaged 23 monkeys that had been living in social groups set to different sizes. Subject comparison revealed that living in larger groups caused increases in gray matter in mid-superior temporal sulcus and rostral prefrontal cortex and increased coupling of activity in frontal and temporal cortex. Social network size, therefore, contributes to changes both in brain structure and function. The changes have potential implications for an animal’s success in a social context; gray matter differences in similar areas were also correlated with each animal’s dominance within its social network.

• Source: Social Network Size Affects Neural Circuits in Macaques, J. Sallet, DOI: 10.1126/science.1210027, Science Vol. 334 no. 6056 pp. 697-700, 2011/11/4

Evolutionary biology: The path to sociality, Nature

Excerpt: (…) some hints about the sequence of events that led to the evolution of human social systems are emerging. The latest evidence comes from Shultz et al.1, who (…) trace the evolution of complex sociality within the order Primates. Their data provide a strong foundation for modelling the origins of hominid mating systems by constraining the range of likely trajectories of social change.

• Source: Evolutionary biology: The path to sociality, Joan B. Silk, DOI: 10.1038/479182a, Nature 479, 182�"183, 2011/11/9

Stepwise evolution of stable sociality in primates, Nature

Excerpt: (…) This supports suggestions that social living may arise because of increased predation risk associated with diurnal activity. Sociality based on loose aggregation is followed by a second shift to stable or bonded groups. This structuring facilitates the evolution of cooperative behaviours5 and may provide the scaffold for other distinctive anthropoid traits including coalition formation, cooperative resource defence and large brains.

• Source: Stepwise evolution of stable sociality in primates, Susanne Shultz, Christopher Opie & Quentin D. Atkinson, DOI: 10.1038/nature10601, Nature 479, 219�"222, 2011/11/9

Martin Hanczyc: The line between life and not-life, TED.com

About this talk: In his lab, Martin Hanczyc makes "protocells," experimental blobs of chemicals that behave like living cells. His work demonstrates how life might have first occurred on Earth ... and perhaps elsewhere too.

• Source: Martin Hanczyc: The line between life and not-life, TED.com, 2011/11
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Daniel Wolpert: The real reason for brains, TED.com

About this talk: Neuroscientist Daniel Wolpert starts from a surprising premise: the brain evolved, not to think or feel, but to control movement. In this entertaining, data-rich talk he gives us a glimpse into how the brain creates the grace and agility of human motion.

• Source: Daniel Wolpert: The real reason for brains, TED.com, 2011/11

Mathematics: Alice in time, Nature

Excerpt: Time haunts both Alice books. Lewis Carroll, author of Alice's Adventures in Wonderland (1865) and Through the Looking-Glass (1871), was also Charles Dodgson, mathematician and logician, and so was aware of the disturbing arguments, new in the mid-nineteenth century, that suggested our view of the geometry of space and time was not universal.
As Dodgson, he was a devout Euclidean, believing that planes are flat and parallel lines never meet. As Lewis Carroll, he stepped across those boundaries.

• Source: Mathematics: Alice in time, Gillian Beer, DOI: 10.1038/479038a, Nature 479, 38�"39, 2011/11/2

Mental problems gave early humans an edge - life - 07 November 2011 - New Scientist

Mental problems gave early humans an edge - life - 07 November 2011 - New Scientist