Interrelation of Morphological Characters in Human Development as Interpreted with the Method of Equiprobable Elipses

Abstract

The paper presents a quantitative analysis of biological distances between children at the age of 3 years and those in successive age groups (4-18 years), as well as respective groups of boys and girls viewed developmentally. The analysis was carried out by investigating the relationship of body weight to thigh circumference using the method of equiprobable ellipses in a system of standardization. As a base for standardization, values of the investigated characters in 3 years old children were taken.

The figure 2 presents a graphical picture of standardized ellipses determined by values of the standard deviation, delimiting respectively 70, 95, and 99 percent of individuals within a population. Circles drawn in this system are the peculiar case of ellipses. Interrelation between characters was analyzed from the angle of places occupied within the population by separate individuals with respect to the pair of investigated characters. The analysis was not based on correlation coefficients, though their values for investigated characters are positive and statistically significant throughout a whole observed period of ontogeny. Such an analysis allows determining what percentage of genotypes does not possess common values between successive age groups within both sexes and between them.

Presented data suggest that each of the characters, in relation to its variance in groups of 3 years old individuals, changes to the same extent (equal distances) in both sexes; however, biological distances between successive age groups (table 1, fig. 3) and sexes (table 2, fig. 4) are different. At the same time, from the data presented in tables 1 and 2, it follows that body weight is decisive for the investigated quantitative variation.