Thursday, April 2, 2020

3/21/20: Book Review: Where Good Ideas Come From by Steve Johnson

This book is a gem of knowledge, starting with the fascinating observations and insights of Charles Darwin and moving through the history of great idea men to today’s Nano technology thinkers. Johnson gives solid, practical insight into where and how human ideas evolve, and advice on the best ways to foster those ideas. 

I found the first half of the book ten times more interesting than the last half, but it still is a worthwhile read cover to cover. One of the most interesting ideas for me, called negative quarter-power scaling, came in the first pages:

Scientists and animal lovers had long observed that as life gets bigger, it slows down. Flies live for hours or days; elephants live for half-centuries. The hearts of birds and small mammals pump blood much faster than those of giraffes and blue whales. But the relationship between size and speed didn’t seem to be a linear one. A horse might be five hundred times heavier than a rabbit, yet its pulse certainly wasn’t five hundred times slower that the rabbit’s. After a formidable series of measurements in his Davis lab, Kleiber discovered that this scaling phenomenon stuck to an unvarying mathematical script called “negative quarter-power scaling.” If you plotted mass versus metabolism on a logarithmic grid, the result was a perfectly straight line that led from rats and pigeons all the way up to bulls and hippopotami. 

Physicists were used to discovering beautiful equations like this lurking in the phenomena they studied, but mathematical elegance was a rarity in the comparatively messy world of biology. But the more species Kleiber and his peers analyzed, the clearer the equation became: metabolism scales to mass to the negative quarter power. The math is simple enough: you take the square root of 1,000, which is (approximately) 31, and then take the square root of 31, which is (again, approximately) 5.5. This means that a cow, which is roughly a thousand times heavier than a woodchuck, will, on average, live 5.5 times longer, and have a heart rate that is 5.5 times slower than the woodchuck’s. As the science writer George Johnson once observed, one lovely consequence of Kleiber’s law is that the number of heartbeats per lifetime tends to be stable from species to species. Bigger animals just take longer to use up their quota.

Over the ensuing decades, Kleiber’s law was extended down to the microscopic scale of bacteria and cell metabolism; even plants were found to obey negative quarter-power scaling in their patterns of growth.  Wherever life appeared, whenever an organism had to figure out a way to consume and distribute energy through a body, negative quarter-power scaling governed the patterns of its development.

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