morphometrics

Measurement of the range and relative proportions of morphological characters of an organism, commonly used in the scientific description of a species. In fish, for example, morphometrics often include the ratio of predorsal length to the standard length or the ratio of body depth to the standard length. Ratios are almost always preferred to absolute measurements since they remove significant variation due to size. However, some ratios may pose problems because of allometry in growth: juveniles may be more slender. (Yes, it happens in fish, too.)

Morphometrics is the branch of mathematics concerned with the metrical and statistical properties of shapes and changes in shapes. It is applied to the study of geometric objects, such as molecules, fossils, brains, bird wings, ancient handcraft, modern cars, etc.

The numerical methods used in morphometric research are very advanced, and include various oridination procedures (Canonical Correlation Analysis, Principal Components Analysis, Relative Warps Analysis, Thin-plate splines, Fourier Analysis, Fractal Analysis, etc.).

In biology it can be used to examine or create taxonomic classifications, or examine such life history questions as pertain to phenotypic plasticity, and adaptation. It can also be applied in chemistry and engineering, and has been used to help render manufacturing processes more efficient.