Living and the Non-Living organisms, Metabolism, Growth and Development

Living and the Non-Living

If we chemically analyse a living organism, plant or animal, we find that it is made up of carbon, hydrogen, oxygen, nitrogen and a few other elements. However, a mixture of these elements does not make a living organism. Then, how do we define life. It is difficult to arrive at a universal definition of life. Nevertheless, it is possible to characterise living things. We may say that living organisms are those characterised by the following features.

(i) Organisation All living organisms have a definite shape and size as well as physical and chemical composition inherited from their parents. This is possible because of a high degree of organisation. The molecules of which an organism is made up are organised into cells, which in turn are organised into tissues, organs and organ systems making the whole individual. This kind of complex organisation is not found in non-living things.

(ii) Metabolism Green plants obtain their nourishment from the environment in the form of water, carbon dioxide, and certain minerals which are utilised to synthesize carbohydrates during photosynthesis. Carbohydrates are in turn broken down during respiration and the energy thus released is used to synthesize other organic compounds like lipids, proteins, nucleic acids, etc. which make up the body. Animals, bacteria and fungi, on the other hand, obtain nourishment in the form of organic compounds and utilise them to synthesize compounds they need. Such reactions do not occur in non-living objects.

(iii) Growth and Development Living organisms often arise from a single cell which divides and re-divides to form a large number of cells that differentiate into the various organs of the body. These kind of phenomena are not known in the non-living world.

(iv) Reproduction Living organisms, unlike non-living, are universally recognised by their capacity to multiply their own types by means of asexual or sexual reproduction.

(v) Responsiveness All living organisms respond to stimuli, e.g., roots move towards the earth and shoots toward the sun, stomates open during the day and close during the night, and the dog wags its tail on seeing its j master. This kind of response does not occur in the non­living.

(vi) Adaptation    Organisms have the ability to adapt themselves to the needs of the environment which helps j them to survive. For example, plants growing in saline soils have a high-concentration of salts in their body and those in deserts have few leaves with thick waxy coatings. Likewise, animals living in cold climates have a thick coat of hair on the body and a chameleon can change its body colour according to its surroundings.

Growth and Development

Growth and Development

Human growth is sensitively balanced complex of processes in which body structure, physiological function and emotion each plays its indispensable role and a disturbance or deficiency of one factor can seriously affects the others. The term growth, development and maturity often are used as synonymously but they are not identical. They are interdependent processes associated with the period from fertilization of ovum to maturity.  

Growth can be defined as permanent increase in the size and form mostly accompanied by increase in weight. It is the objective manifestation of hypertrophy and hyperplasia of the organic constituent tissues determined by pre-established hereditary factors. Exogenous factors, however, can also influence this phenotypic expression of organism heredity in form of growth. Tanner (1962) considers growth as ‘Form of motion’.

Growth is complex and highly integrated process and may be defined as the production of new biochemical units through biochemical and biological synthesis. In quantitative terms, growth is the increase in living substance or protoplasm and includes one or more three processes – cell multiplication, cell enlargement and incorporation of material taken from environment. Development can be defined as the qualitative aspects of growth.

The British medical dictionary defined the growth as the progressive development of a living being or part of the organisms from its earlier stage to maturity including the attendant increase in size. In the same dictionary development is defined as the series of changes by which individual embryo become a mature organism. Growth involves a series of changes, not just the addition of material to achieve in increase in size. These changes include a specialization of various parts of the body as a whole as well as in the forms of its individual organs and system. Material such as bone or fat is added, but other material is actually subtracted, e.g. the thyrus gland which is large in the childhood gradually decreases degenerates.

Growth times include the identical destruction and death of cells and tissues, which is programmed sometimes. Growth may be involve also substitution e.g. conversion of cartilage into bone. Growth of the whole living body and growth of its parts are distinguished because not all parts of the body grow at the same rate. Nor they all stop growing simultaneously. Further, the growth of one part may be controlled by the activity of another and the degree of control depends upon the development of the controlling part. The body does not, therefore, retain the same proportions throughout the period of growth and the relative weights and sizes of given tissues and organs do not remain constant.  This differential growth also implies movement of one part relative to another. Growth does not cease when maturity is attained e.g. the lining of alimentary tract is constantly removed and nearly every tissue and organ there is recurring cycle of the growth, death and replacement.

According to Webster dictionary; growth is to increase in size by addition of material either by assimilation into the living organism or by accretion in a non- biological process. According to Swatland it is an increase in height, length, girth, and weight that occurs when a healthy young animal is given adequate food, water, and shelter. Live weight is the most important and most commonly measured of these parameters and, if recorded at regular intervals, yields a simple growth curve.

Growth and development are two interlinked and simultaneous process. When a child is growing, he / she are also developing side by side. Changing structure and function in child are inseparable.

Development refers as increase in complexity of the animal system. To set forth or make clear by degrees or in detail; to cause to grow and differentiate along lines natural to its kind; to go through a process of natural growth, differentiation, or evolution by successive changes.

According to Swatland development is the sum of growth plus differentiation, where differentiation was isolated from its histological connotations and was defined as the process in which parts of an animal change in their relative proportions.

 Growth:

1.      It is physical change and increase in size.

2.      It can be measured quantitatively.

3.      Indicators of growth include height, weight, bone size, and dentition.

4.      Growth rates vary during different stages of growth and development.

5.      The growth rate is rapid during the prenatal, neonatal, infancy and adolescent stages and slows during childhood.

6.      Physical growth is minimal during adulthood.

Development:

1.      Is an increase in the complexity of function and skill progression.

2.      It is the capacity and skill of a person to adapt to the environment.

3.      Development is the behavioral aspect of growth.