What has to developed?

The physical growth in stature and the weight take place in the 15-20 following years to the birth, since the individual changes from the weight average of 3.5 kg and length of 50 cm when being born upon maturity with the size of adult. As stature and increase of weight, proportions of the individual also change, the head relatively great and the torso and the small extremities of new born, at the top relatively small one of the adult and length torso and the extremities.

The speed and the pattern of development

The speed of the physical growth is fast in the months after the birth, and soon it diminishes, reason why the weight when being born is duplicated in the first four months, was tripled in 12 months of age, but it was not quadruplicated until the 24 of months. Growth comes then to a slow rate until shortly before the puberty (between 9 and 15 years of age), when a period of fast growth takes place. The growth is not uniform in the rate and the moment in all the parts of the body. When being born, the size of the head already is relatively next to the one of an adult, but the inferior parts of the body are much more small that the adult size. In the course of the development, then, the head grows relatively little, and the torso and the extremities to be put under a great amount of growth.

The mechanisms of the evolutionary change

The genetic factors play an important role in the determination of the rate of growth, and in individual the changes in the characteristics proportion of human development early. Nevertheless, the genetic factors can only produce the maximum growth if the environmental conditions are adapted. The bad nutrition and frequent injuries and the disease can reduce the stature of the adult individual, but best environment cannot cause the growth of a stature greater than it is determined by the inheritance.

Population of the differences

Differences in the growth of the population is to a great extent due to the stature of the adult. The ethnic groups that are enough stops in the adult age also are already in the birth and during all the childhood, in comparison with the groups that have a short adult stature. The men also are something more stops, although this is more evident in the ethnic groups with strong sexual dimorphism in the adult age. The populations that characterize themselves for being undernourished they are also shorter during all the life. Nevertheless, there are few differences in the rates of growth of the population or the patterns, with the exception that the bad environmental conditions can delay to the puberty and the acceleration of the growth associate. The age remarkably different in the puberty from children and children means that the children and children of 11 or 12 years are in very different points in the maturation and can revert the sex difference is habitual in physical size.