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Life is built of symmetrical structures. But why? Sachin Rawat explores…

Life comes in a variety of shapes and sizes, but all organisms generally have at least one feature in common: symmetry.

Notice how your left half mirrors the right or the radial arrangement of the petals of a flower or a starfish’s arms. Such symmetry persists even at the microscopic level, too, in the near-spherical shape of many microbes or in the identical sub-units of different proteins.

The abundance of symmetry in biological forms begs the question of whether symmetric designs provide an advantage. Any engineer would tell you that they do. Symmetry is crucial to designing modular, robust parts that can be combined together to create more complex structures. Think of Lego blocks and how they can be assembled easily to create just about anything.

However, unlike an engineer, evolution doesn’t have the gift of foresight. Some biologists suggest that symmetry must provide an immediate selective advantage. But any adaptive advantage that symmetry may provide isn’t by itself sufficient to explain its pervasiveness in biology across scales both great and small.

Now, based on insights from algorithmic information theory, a study published in Proceedings of the Natural Academy of Sciences suggests that there could be a non-adaptive explanation…

Symmetrical objects are less complex than non-symmetrical ones. Perhaps evolution acts as an algorithm with a bias toward simplicity: “Simple is beautiful: Why evolution repeatedly selects symmetrical structures,” from @sachinxr in @bigthink.

* Frank Wilczek (@FrankWilczek)

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As we celebrate symmetry, we might recall (speaking of symmetry) that it was on this date in 1963 that the Equal Pay Act of 1963 was signed into law by president John F. Kennedy. Aimed at abolishing wage disparity based on sex, it provided that “[n]o employer having employees subject to any provisions of this section [section 206 of title 29 of the United States Code] shall discriminate, within any establishment in which such employees are employed, between employees on the basis of sex by paying wages to employees in such establishment at a rate less than the rate at which he pays wages to employees of the opposite sex in such establishment for equal work on jobs[,] the performance of which requires equal skill, effort, and responsibility, and which are performed under similar working conditions, except where such payment is made pursuant to (i) a seniority system; (ii) a merit system; (iii) a system which measures earnings by quantity or quality of production; or (iv) a differential based on any other factor other than sex […].

Those exceptions (and lax enforcement) have meant that, 60 years later, women in the U.S. are still paid less than men in comparable positions in nearly all occupations, earning on average 83 cents for every dollar earned by a man in a similar role.

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