viernes, 25 de noviembre de 2011

Compilado AZyNE 25-11

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

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.

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.

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

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