21 JUL 2011 by ideonexus

 Theories on Handedness

Because it develops so early, this brain asymmetry appears to be largely innate. It is possible, however, that environmental factors begin operating even before birth. One hypothesis is that the right hand becomes more skillfull because it has greater freedom to move in the womb. About three-quarters of all fetuses spend the last several weeks of gestation with their right arm facing out—toward the mother's abdominal wall. This arm has more space in which to move than does the left arm, whi...
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Three hypotheses for why right-handedness is the dominant trait in humans.

20 MAY 2011 by ideonexus

 An Origami Metaphor for Fetal Development

The sheets of tissue that fold, invaginate and turn inside out in a developing embryo do indeed grow, and it is that very growth that provides part of the motive force which, in origami, is supplied by the human hand. If you wanted to make an origami model with a sheet of living tissue instead of dead paper, there is at least a sporting chance that, if the sheet were to grow in just the right way, not uniformly but faster in some parts of the sheet than in others, this might automatically cau...
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Cells divide and fold into new forms, just as origami structures become other structures through new folds.