The biological meaning of life is reduced to the reproduction of species. Here, reproduction is considered as a barrier process leading from an adult organism to a newly formed one. Moreover, only a small part of organisms is able to reproduce almost immediately, as it appeared itself. These are the simplest bacteria that can divide within 20 minutes from the start of life. Others, in order to start multiplying, need to grow and develop.
General concept of growth and development
So, living beings inhabit the planet and live on it. A huge number of them, which cannot be counted, is reproduced during the day, weeks, months, and years. For reproduction, many do not need to acquire new functions, that is, additional to those that they received after their appearance. But most others need it. They just need to grow, that is, increase in size, and develop, that is, acquire new functions.
Growth is called the process of increasing the morphological size of the body. A newly formed living creature must grow in order to start its metabolic processes at the most active level. And only with an increase in body size can the appearance of new structures guarantee the development of certain functions. Therefore, the growth of the body and the development of the body are related processes, each of which is a consequence of each other: growth provides development, and further development increases the ability to grow.
Private understanding of development
The growth and development of the body are connected by the fact that they run parallel to each other. Previously, it was understood that the creature must first grow, and the new organs that guarantee the emergence of new functions will be located in a supposedly vacated place in the internal environment of the body. About 150 years ago, there was an opinion that growth occurs first, then development, then growth again, and so on in the cycle. Today, understanding is completely different: the concept of growth and development of an organism denotes processes that are not identical, but occur together.
It is noteworthy that in biology there are two types of growth: linear and volumetric. Linear is the increase in the length of the body and its sections, and volumetric is the expansion of the body cavity. Development also has its own differentiation. Individual and species development are distinguished. Individual means the accumulation of certain functions and skills by one organism of the species. And species development is the improvement of a new species, capable of, for example, adapting slightly to living conditions or populating previously uninhabited areas.
The ratio of growth and development in unicellular organisms
The lifespan of unicellular organisms is the period that a cell can live. In multicellular organisms this period is much longer, and that is why they develop more actively. But unicellular (bacteria and protists) are too volatile creatures. They mutate actively and can exchange genetic material with representatives of various strains of the species. Therefore, the development process (in the case of gene exchange) does not require an increase in the size of the bacterial cell, that is, its growth.
However, as soon as the cell receives new hereditary information through the exchange of plasmids, protein synthesis is required. Heredity is information about its primary structure. It is these substances that are an expression of heredity, since a new protein guarantees a new function. If a function leads to increased viability, then this hereditary information is reproduced in future generations. If it does not bear any value or even harms, then cells with such information die, because they are less viable than others.
The biological significance of human growth
Any multicellular organism is more viable than a unicellular one. In addition, it has much more functions than a single isolated cell. Therefore, the growth of the organism and the development of the organism are the most specific concepts for multicellular ones. Since the acquisition of a certain function requires the appearance of a certain structure, the processes of growth and development are as balanced as possible and are mutual "engines" of each other.
All information about the abilities to which development is possible is embedded in the genome. Each cell of a multicellular creature contains the same genetic set. In the early stages of growth and development, one cell divides multiple times. Thus, growth occurs, that is, an increase in the size necessary for development (the emergence of new functions).
Growth and development of multicellular different classes
As soon as the human body is born, the processes of growth and development are balanced among themselves until a certain period. It is called linear growth arrest. Body sizes are embedded in the gene material, as well as skin color and so on. This is an example of polygenic inheritance, the laws of which have not yet been sufficiently studied. Nevertheless, normal physiology is such that the growth of the body cannot continue indefinitely.
However, this is mainly characteristic of mammals, birds, amphibians, and some reptiles. For example, a crocodile is able to grow all its life, and its body size is limited only by the life span and some dangers that can await it in its course. Plants do grow all their lives, although, of course, there are artificially grown species in which this ability is in some way suppressed.
Features of growth and development in biological terms
The growth of the body and the development of the body are aimed at solving several problems that are related to the fundamental properties of all living things. Firstly, these processes are necessary for the implementation of hereditary material: organisms are born immature, grow, acquire the function of reproduction throughout life. Then they give posterity, and the reproduction cycle itself is repeated.
The second meaning of growth and development is the settlement of new territories. It would not be unpleasant to be aware of this, but nature in every form has a tendency towards expansion, that is, the settlement of as many territories and zones as possible. This gives rise to competition, which is the engine of species development. The human body also constantly competes for its habitat, although this is now not so noticeable. Basically, he has to deal with the natural defects of his body and the smallest pathogens.
Growth Basics
The concepts of "growth of the organism" and "development of the organism" can be considered much deeper. For example, growth is not only an increase in size, but also a multiplication of the number of cells. Each body of a multicellular organism consists of many elementary components. And in biology, the elementary units of the living are cells. And although viruses do not have cells, but are still considered living, this concept needs to be reviewed.
So, but the cell is still the smallest of all balanced systems that can live and function. In this case, an increase in the size of the cell and extracellular structures, as well as an increase in their number, is the basis of growth. This applies to both linear and volumetric growth. Development also depends on their number, because the more cells, the larger the size of the body, which means that the more spacious the organism can populate.
The social significance of human growth
If we consider the processes of growth and development only on the example of man, then a paradox appears here. Growth is important because the physical development of a person is the main driver of reproduction. Persons who are physically undeveloped are often not able to give viable offspring. And this is the positive meaning of evolution, although, as a fact, it is negatively perceived by society.
It is the presence of society that is a paradox, because under its protection even a physically undeveloped person, due to enviable intellectual abilities or other achievements, is able to marry and give birth. Of course, normal physiology does not change its principles in people who do not have diseases, but are physically less developed than others. But it is obvious that body size is a genetic dominant. Since they are smaller, it means that a person is less able than others to adapt to changing living conditions.
Human development in society
Although the person has adapted the living conditions for himself, he is still faced with adverse factors. Surviving them is a matter of fitness. But here there is another biological paradox: today man survives in society. This is a conglomerate of people that equalizes the chances of everyone to survive in certain situations.
The biological instincts of preserving the species also work here, because in the most terrifying situations, few individuals care only about themselves. Therefore, since it is beneficial for us to stay in society, it means that the development of the human body is impossible without it. Man has even developed a language for communication in society, and therefore one of the stages of personal and species development is its study.
From birth, a person is not able to speak: he only makes sounds that demonstrate his fear and irritation. Then, as he develops and finds himself in a linguistic environment, he adapts, speaks the first word, then enters into full-fledged speech contact with other people. And this is an extremely important period of its development, because without society and without adaptation to living in it, a person is least adapted to life in the current conditions.
The periods of development of the human body
Every organism, especially a multicellular one, goes through a series of stages in its development. They can be considered on the example of man. From the moment of conception and the formation of a zygote, it goes through the stages of embryogenesis and fetogenesis. The entire process of growth and development from a unicellular zygote to the body takes 9 months. After birth, the first stage of the body's life begins outside the maternal womb. It is called the neonatal period, which lasts 10 days. The next one is infancy (from 10 days to 12 months).
After infancy, early childhood begins, which lasts up to 3 years, and from 4 to 7 years, an early childhood period begins. From 8 to 12 years for boys, and for girls under 11 years, the period of late (second) childhood lasts. And from 11 years to 15 in girls and from 12 years to 16 in boys, the teenage period lasts. Boys become boys from 17 years old to 21 years old, and girls from 16 to 20 years old. This is the time when children become adults.
Adolescent and adult
By the way, from the teenage period it is wrong to call the heirs children. They are young men who from 22 to 35 years old are experiencing their first mature age. The second mature in men begins at 35 and ends at 60, and in women from 35 to 55 years. And from 60 years to 74 years old age begins . Age-related physiology very revealingly reflects the changes that occur in the human body over the course of life, but geriatrics is engaged in diseases and life features of the elderly.
Despite medical measures, mortality during this period is the highest. Since the physical development of a person here stops and tends to involution, there are more and more bodily problems. But development, that is, the acquisition of new functions, practically does not stop, if we consider it mentally. In terms of physiology, development undoubtedly also seeks involution. It reaches a maximum in the period from 75 to 90 years (senile) and continues among long-livers who have overcome the age barrier of 90 years.
Features of growth and development in periods of life
Age-related physiology reflects the characteristics of development and growth in various periods of life. She focuses on biochemical processes and important mechanisms of aging. Unfortunately, there is no way to effectively influence aging, so people are still dying due to damage accumulated over their lives. The growth of the body ends after 30 years, and, according to many physiologists, already at 25 years old. At the same time, physical development stops, which can be re-launched with hard work on oneself. At different periods of development, you should work on yourself, because this is the most effective evolutionary mechanism. After all, even strong genetic inclinations cannot be realized without training and practice.