A flexible 3-parameter curve for limited or unlimited somatic growth.

摘要: Unlike population growth, the somatic growth of individual organisms is often well described by a curve passing through origin, provided time (t) measured from moment at which egg starts developing actively. A simple 3-parameter asymptotic curve, X = A/(1 + D/tc), can be derived logistic A/[1 D/exp(Ct)], replacing its natural logarithm. Hill (1913) used similar to describe saturation haemoglobin oxygen, but he considered only exponents C greater than or equal 1. Depending upon value exponent C, this has flexible shape range all way rotated and translated rectangular hyperbola sigmoid curve. When 1, there an inflection point ordinate assume any between 0 A/2, where denotes (upper) asymptote. less if pattern appears unlimited, within data, becomes allometry with respect time, Btc. The asymptote then large ratio parameters A/D approaches B as limit. other curves, present shows acceptable numerical convergence when fitted both limited unlimited data. This illustrated data on body length male female elephant seals weight yellow sturgeons.