concept

Isometry

The case where a body grows while keeping its shape and proportions identical - every length changes by the same factor. Isometry is the baseline for comparison: in reality most organisms do NOT grow this way, because the square-cube law means an isometrically enlarged animal would break its own bones under its weight. When a biological measure departs from isometry - bone thickening faster than length, say - we call it allometry. Measuring the departure from isometry is therefore how we detect the ways a body has been forced to change shape to cope with size.