There are several factors which directly or indirectly influence the growth and development of an organism. There are as follows:
(i) Heredity, (ii) Environment, (iii) Sex, (iv) Nutrition, (v) Races, (vi) Exercise, (vii) Hormones, (viii) Learning and Reinforcement.
Heredity is a biological process through which the transmission of physical and social characteristics takes place from parents to off-springs. It greatly influences the different aspects of growth and development i.e. height, weight and structure of the body, colour of hair and eye, intelligence, aptitudes and instincts.
However environment equally influences the above aspects in many cases. Biologically speaking heredity is the sum total of traits potentially present in the fertilized ovum (Combination of sperm cell & egg cell), by which off-springs are resemblance to their parents and fore parents.
Environment plays an important role in human life. Psychologically a person's environment consists of the sum total of the stimulations (physical & Psychological) which he receives from his conception. There are different types of environment such as physical, environment, social environment & psychological environment.
Physical environment consists of all outer physical surroundings both in-animate and animate which have to be manipulated in order to provide food, clothing and shelter. Geographical conditions i.e. weather and climates are physical environment which has considerable impact on individual child.
Social environment is constituted by the society-individuals and institutions, social laws, customs by which human behavior is regulated.
Psychological environment is rooted in individual's reaction with an object. One's love, affection and fellow feeling attitude will strengthen human bond with one another.
So Growth and Development are regulated by the environment of an individual where he lives.
Sex acts as an important factor of growth and development. There is difference in growth and development of boys and girls. The boys in general taller, courageous than the girls but Girls show rapid physical growth in adolescence and excel boys. In general the body constitution and structural growth of girls are different from boys. The functions of boys and girls are also different in nature.
Growth and Development of the child mainly depend on his food habits & nutrition. The malnutrition has adverse effect on the structural and functional development of the child.
The racial factor has a great influence on height, weight, colour, features and body constitution. A child of white race will be white & tall even hair and eye colour, facial structure are governed by the same race.
This does not mean the physical exercise as a discipline. The functional activities of the child come in the fold of exercise of the body. We do not mean any law of growth through use or atrophy (The reverse of growth) through disuse.
The growth of muscles from the normal functioning of the child is a matter of common knowledge. It is a fact that repeated play and rest build the strength of the muscle. The increase in muscular strength is mainly dye to better circulation and oxygen supply. The brain muscles develop by its own activity-play and other activities provide for these growth and development of various muscles. Deliberately the child does not play or engages himself in various other functions with the knowledge that they will help him in growing. This style of functioning of the child is but natural.
There are a number of endocrine glands inside the human body. Endocrine glands are ductless glands. This means there are certain glands situated in some specific parts of the body. These glands make internal secretions locally. These secretions produce one or more hormones.
Hormones are physiological substances having the power to raise or lower the activity level of the body or certain organs of the body. For example, the gland pancreas secretes pancreatic juice, not into the blood, but into the intestine. Here it acts upon food and plays an important part in digestion of food. This pancreas also discharges into the blood, a substance called insulin. This being carried by the blood to the muscles enables them to use sugar as a fuel to add strength to muscles. It the pancreas fails to produce the secretions, the organism lapses to the unfavorable conditions of growth and development.
Similarly, the adrenal glands are very close to kidneys. These make a secretion of adrenaline, a very powerful hormone, which is responsible for strong and rapid heart-beat, release of stored sugar from liver and which controls blood pressure. Gonads are glands, which secrete hormones that have important effects on growth and sex behavior.
A balance of male hormones controls development in the direction of masculinity and that of female hormones steers it toward feminist. At puberty, these sex hormones promote the development of genital organs. Lacking the gonads, individuals of either sex develops into rather a neutral specimen without strong sex characteristics. Pituitary is called the "master gland". It is attached to the under side of the brain and its secretions controls the brain function and also the blood pressure. It stimulates other glands like adrenal and gonads. If this gland is over-active in childhood, the muscles and bones grow very rapidly and the individual may become a giant of seven to nine feet tall.
8. Learning and Reinforcement
Learning is the most important and fundamental topic in the whole science of psychology. Development consists of maturation and learning. Without any learning the human organism is a structure of various limbs, all other internal organs with muscles and bones. But it is not human being with maturation.
Learning includes much more than school learning. Learning goes to help the human child in his physical, mental, emotional, intellectual, social and attitudinal developments. All knowledge and skill, all habits, good and bad, all acquaintances with people and things, all attitudes built up in your dealing with people and things have been learned.
Reinforcement is a factor in learning. Exercise or activity is necessary for learning. It may be a motor activity, as in playing on a musical instrument. Or it may be a sensory activity as in listening to a piece of music. Whatsoever, there most be activity in some from. "We learn by doing". It is an old psychological proverb. Now it is that out activity should be repeated till we get the desired results. So the proverb should be, "We learn by doing getting results."