Ontogenesis of Man

This book describes the mysterious story and the sequence of events involved in growth and development of man, which start to take place early during conception when one single egg is fertilized by one single sperm to form the embryo, who continues to grow and mature inside the uterus of its mother for ten lunar months. After birth, through a series of complex, fascinating changes acting in concert together during infancy, childhood, and adolescence, the child is modeling his or her characteristics and progresses from dependency to increasing autonomy, changing his or her shape and body proportions from those of the baby to those of adults to become a man or a woman. With the onset of puberty, shortly before the end of the growth period, dramatic changes occur to the growing child involving physiological, mental, and sexual changes triggered by maturation of the sex glands and the endocrine system.

These events are important to the child, his parents, and the community. There is marked acceleration of growth known as the adolescence growth spurt, appearance of second sexual characters, and onset of menarche in girls. At puberty, sex dimorphism is made clear, like wider shoulders in males and larger hips in females. Different stages of puberty occur at different ages in different children, depending whether the child is early or late maturer, and the sequence in which they occur varies from one child to another. Some pass through the whole sequence of changes quite quickly while others take much longer to do so, but all are normal variations among healthy children. The problems of early and late maturation and chronological and physiological ages among children and its social impact are discussed. This period is the most crucial period of life, physical maturation is reached, internal conflicts flare up, adolescents feel a desire to abandon childhood security and become independent long before they are able to handle the complexities of life.

Many factors are involved before and after birth. Man is considered the product of the interaction between his genetic makeup and the environment in which he is born and lives. Secular trend toward increase in size and early maturation from generation to generation was discussed as well as the effects of modern technology and how it changed the way children live nowadays. Applicability of growth data in fields other than community child health like ergonomics, garment industry, and athletics was demonstrated. Brief description of the common growth disorders was given.

After adulthood comes elderhood. Signs of aging start to appear. End of independency and second childishness bring man to his final destination, which mark the end of a process of growth, which, since middle life, has been fighting a losing battle with the forces of degeneration. This is one that every living organism in our planet has experienced.