= Scale =
==== The Universal Laws of Growth, Innovation, Sustainability, and the Pace of Life in Organisms, Cities, Economies, and Companies ====
== Geoffrey West 303.44 WES 2017 Beavertin Library ==

------

Great ideas.  A fat book that should have been leaner - though it could have been more explicit about unsolved problems and open questions.

A couple of math goofs:

------
Page 119:  ... "our capillaries are only 5 micrometers wide (about a ''hundredth of an inch''), which is somewhat smaller than a hairbreadth"

 . [[ https://en.wikipedia.org/wiki/Capillary | A capillary is a small blood vessel from 5 to 10 micrometres (μm) in diameter, and having a wall one endothelial cell thick. ]]

 . [[ https://hypertextbook.com/facts/1999/BrianLey.shtml | hair diameter is 17 to 181 micrometers ]].  

An inch is 25.4 millimeters, or 25400 micrometers, so capillaries are '''about __0.2 thousandths__ of an inch, or __0.2 mils__''' or 200 millionths of an inch.  Inches are a weird archaic unit, so it is unsurprising that a particle physicist (trained to work with vastly smaller metric units, not mixed engineering units) doesn't notice this error.

-----

Page 125:   "shrew's heart" ... and  ... "whale's heart" ...  "This is pretty amazing -- just think of the enormous stresses on the walls of the shrew's tiny aorta and arteries compared with the pressures on yours or mine, let alone those on a whale's.  No wonder the poor creature dies after only a year or two."

 . The wall stress of a pressure vessel is proportional to the pressure times the radius.  That stress is accommodated by the tensile strength of the vessel wall material (collagen? muscle?) multiplied by thickness.  A shrew and a whale both use the same materials - and the shrew needs a proportionally thinner wall to accommodate the proportionally smaller stress.  One to one scaling.  A shrew's lifetime is short because its metabolism runs faster; species survival is optimized by devoting resources to fast reproduction, not individual longevity.