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Regional Trends in Geographic Variation
Leslie F. Marcus and John H. Vandermeer
Vol. 15, No. 1 (Mar., 1966), pp. 1-13
Stable URL: http://www.jstor.org/stable/2411497
Page Count: 13
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Geographic variation of quantitative characters may be represented by a polynomial model and plotted automatically as a contour map with a digital computer. Linear, quadratic, and cubic surfaces are fitted to the variation patterns of two characters of the fathead minnow, Pimephales promelas, from 54 localities distributed over a large area of North America. The cubic surfaces describe the variation pattern quite well and account for as much as 90% of the variability among localities. Regional trends are simply represented by the contour plots, while local variability and breaks in the variation pattern may be analyzed by examination of the automatic plots of residuals.
Systematic Zoology © 1966 Oxford University Press