What is ontogeny?

The ontogeny - it is the individual development of the organism since its inception (zygote) to natural death. There are two periods of ontogenesis:fetal (embryonic) and post-embryonic (poslezarodyshevy). Fetal covers conversion zygote to embryo and the development of the embryo and fetus at the time of birth. Postembryonal begins after birth.

During the life in the human body continuously occurring processes of growth and development. In different periods of lifeand intensity of these processes is not the same, resulting in specific anatomical, physiological and psychological characteristics, which are called age. According to the age characteristics of the entire life cycle of the organism of man is divided into periods. Between them there are no clear boundaries. To a certain extent they are conditional. But the allocation of tAkiho periods necessary to determine the chronological (passport) and biological age.

The chronological age - is the period (in years, months, days), lived from birth to a certain moment counted. Biological age - a collection of anatomical and physiological characteristics of the organism, respondingMac hining age norms for a particular community of people. It depends on the individual rate of growth, development and aging. The difference between chronological and biological age at maturation stage can reach five years, and at the stage of aging - up to 20 years.

The periodization of individual development based on biological, etc.Iznak or social principles. The biological characteristics include changes in growth, development and aging of the body.

The social principles of periodization age determine the periods of study: pre-preschool age - up to 3 years, pre-school - 3-6 years, school age (6-9, Jr. years, the average - 10-14, Senior - 15-17 years).

Upper specific feature of the person is considered 115-125 years. If the biological age significantly ahead of chronological, it indicates premature aging. In the biological age of the person is also influenced by the socio - economic conditions.

What are the characteristics of developmental periods?

In the chest during growth is accompanied by an increase in height and weight. During this period, the growth of the child increases by about one and a half - two times.

The child at the age of 2.5-3 months stronger neck muscles, and she begins to hold their own head. This promotes the formation of cervical curve. In a five-monthsecond child is so developed muscles of the trunk, it can sit up unaided. Thus develops chest bend. Also worth a look. At the end of the first year of the child falls into the legs. At this time, begins to form the lumbar curvature of the spine. In 1,5-2 years already fully formed all the curves of the spine.

Early Childhood. In eduring this period the growth rate slows, but in the second year is still high (10-11 cm per year), in the third year - 8 cm. At the age of two years ending teething. During this period, children are developing intensively, especially rapidly developing it, and with it the thought.

In the first period of childhood (pre-school) children for the year grow by 5-7 cm. At the age of 5-6 years, there are the first permanent teeth. In this period of development the child perceives a lot of information about the world and actively developed.

The period of the second childhood (school period) is solved in physical, mental and spiritual development. It is divided into junior, middle (youth) and senior (junior)age periods, each of which has its own characteristics. Younger school period is characterized by a slowdown in growth. A child growing up during the year by 4-5 cm. During this period, children begin to learn to master reading and writing, reading, mathematics. During training there is the development of mental abilities of students.