Elmann Creative Corner Natural Science

The Element of Physiology. In whatever form life first because manifest on the earth these must have been embodied the peculiar principle possessed to this day by all the manifest organisms of the vegatable kingdom, and that is the ability to obtain nourishment from non-living or inorganic matter. At a later stage it was possible for one kind of creature or organism to subsist by preying on other kinds, but to begin with the only available foodstuff for building tissue and providing energy was some simple chemical substance, or a group of such substances. The peculiarity of modern vegatable organisms is their ability to subsist almost entirely water from the soil, carbon dioxide from the atmosphere and sunlight. The earliest life forms must have been as simple as this in their requirements. Water from suitably formed soil will contain traces of various chemical compounds in solution and these assist in the tissue-building process. Such compounds are returned to the soil when plants die and decompose, for their remains are then assimilated by the earth. The main body of every plant is built up the action of sunlight on its leaves, this being responsible for a process known as photosynthesis. Moisture taken in at the roots is constantly rising to the leaves where most of it is passed away as a vapour by transpiration. At the same time the leaves breathe in atmospheric carbon dioxide, converting this, with the help of sunlight and a green substance called chlorophyll, into the complex carbon compounds needed for growth. The leaves owe their green colour in chlorophyll. From the date of its first appearance animal life has been dependent upon vegetable life, because the peculiarity of an animal is that it must have food of a self-sufficient kind. Regardless of whether the sun is shining or not the animal must have heat energy and body-building substances, and consequently its food must be a ready-prepared store of all that is essential to its being. The substance of vegetable organisms and of other animals answers to this requirement, which explains why animals live by preying on plants and other animals. The term animal is here used in a very general sense and it includes birds,fishes and even insects. What such creatures need from the atmosphere is not carbon dioxide but pure oxygen, as the food they assimilate is oxidised or burnt in order to make it produce heat. A product of this oxidation is carbon dioxide, so that, whereas plants absorb this gas from the atmosphere, animals give it back again. We can see from this brief account that the entire panorama of life is made possible in the first place by the action of sunlight on green leaves. The energy of the sun breaks up a useless incombustible carbon compound and enables the carbon to enter into new compounds that are the vegetable life. These same compounds, assimilated as food by animals, undergo combustion through being combined with atmospheric, organ, and then give back as animal heat the energy that was derived in the first place from the sun. Once more cycle this compound must again be assimilated by green leaves with the help of sunlight and be re-made into vegetable tissue. Animals that subsist wholly on a vegatable diet are called herbivorous animals; horses, cattle and sheep are examples. Life is rather more complicated for animals needing a diet of animal food; examples of flesh-eating or carnivorous anaimals are wolves, lions and tigers. The human being should be termed omnivorous because his diet includes practically every kind of consumable vegetable and animal food. The relationship between all living hinted at by evolutionary hypothesis of Darwin is borne out by anatomical examination of familiar creatures, and by the identity of their life stories. In his birth, way of life and death, man is essentially the same as dog, cat or any other animal. To all the organs comprising his body there are comparable organs in the bodies of animals. Man`s only claim to superiority over other creatures seems to lie in the exceptional development of the organ called the brain. Mental processes are possible in man that are far beyond anything of which animals are capable. Nevertheless, a careful study of animals shows that they possess a rudimentary power of thought, and when the same trouble normally expended in educating human children is expended in training monkeys, dogs or other higher animals,the results are by no means negligible. A person`s education is not thought complete nowadays unless he knows something about his own body, and to conclude this book a few notes will be given on the complicated mechanism that is ourselves.