Peper 12

Why the body size of the mammals are different?

Ramin Amir mardfar


  Why the body size of the mammals are different?

Why the body size of the mammals is different? Previously we knew that there is a direct relationship between the strength of the circulatory system of animals and the largeness of animal and their bodies. The animals which have a weak circulatory system are smaller and which have a complete and strong circulatory system is bigger than the other. So, we see that there are more differences in body size of mammal. The mammals, which have complete and strong circulatory system, must have large bodies, but in fact, it has not been so, and we see small bodies among them! What is the reason? Previously we knew that small animal's whit rapid and more power of propagation, are adjusting themselves with natural changes timely, and continue to survive their generation. In fact to struggle whit the changes of nature, specially, specially the increase of gravity, the animals of each class should remain small enough to make desirable motions and to produce evolutes, whit their rapid propagation. Otherwise, if all of the animals belonged to one class were large, they will not be able to produce desirable animals in appropriate time, so they will be extinct. For example when dinosaurs existed, if all of the reptiles were large, and there were no small reptile, they wouldn't be able to evolutes their circulatory system against the increase of gravity in appropriate time and produce mammals, and they would be extinct by the increase of gravity. But the nature, by the use of suitable methods, maintain some species smaller despite their complete and strong circulatory system, so that they could have enough speed of propagation to produce desirable genes. But how does the nature do this? How can prevent the growth of the body of the animal which has strong and complete circulatory system and keep it smaller? Consider a mountainous area on which some villages are located. Some of the villages are located on the foot of the mountain and some of them are located on the heights. A railroad connects these villages to each other and the train moves on this railroad and brings food for these villages. In animals, the residents of the villages are the cells of animals' bodies. The vessels are like rail and the heart is like the engine of the train. As we knew, there are no blood vessels in insect, that is they don't have railroad, so the train is able to go to farther village and brain food for them, as a result, the residents live only in the village is near to the heart. That is, the body size of the insect must be small. In the amphibian and reptiles there is railroad and also train, but the power of the engine of the train is less and can not draw the train to upper parts so the train to upper parts so the villages have to be arranged horizontally and not to be situated in mountainous areas and high places. That is the body of the animal can't be situated vertically and it has to lie down on earth. In mammals which have both the railroad and the train whit powerful engine, the villages are able to be situated even on the top of the mountains and its residents can receive food and other requirements. That is the mammals can make their bodies larger and they can make the themselves as tall as the giraffe. But we see small bodies among the mammals, too. In their bodies there are both railroad and the train with powerful engine, so why do they have small bodies? The railroad acts like the vessels and the engine of the train acts like the heart and the heart and the train itself acts like the blood. But there are red cells in the blood containing hemoglobin which carry the oxygen. It is like this that there are boxes on the wagons of the train in which the food is being carried and when the train passes through one of villages some of these boxes are opened and the food is given to the residents of the villages. Then the train arrives at the other village and some of the boxes are opened there and the food fall in the village and the villager use them, so as the train passes through the villages, some pf the boxes are opened and the residents receive their required food. At last, when the train arrives at the last village, the boxes are opened, and the train become empty, and returns to the foot of the mountain, loads there, and repeats the operation. In the blood of the animals the red cells do an action like the action of the boxes of the train. At the time of departure, they become full of oxygen and when passing through the tissues empty their oxygen by turn and when all of them empted their oxygen they return to their initial position, and repest the operation again. But when the train passes through a village. How many of the boxes should be opened? The train arrives at the village, all of the boxes are opened there, and the foods fall there. The train moves to the other village, but there is no food to give to its residents. Although, railroad continues up to the upper villages and the engine has the power to go up, but there is no food to give to their residents, so the train returns. So the residents of the upper village die because of the lack of the lake of the food, and the village disappears. That is the body of the animal remains small. Also in the body of the animals, if all of the red cell of the blood release their oxygen in near distance such an action will occur and only the cells and tissues which are near to the heart will survive. That is the animal has to remain small and has not to get larger. In the body of a mouse such event occurs, and all of the oxygen separate from the hemoglobin whit in near distance red cells is emptied. In other animals which are larger, the oxygen attaches to the hemoglobin intensively and is emptied some farther. So according to the largeness of the body of the mammals, the force of attachment of the oxygen to hemoglobin becomes stronger, and it can course a long distance in the body of the animal. But, which factor controls the degree of the attachment of the oxygen to hemoglobin and its early or late release? Organic phosphates like DPG which exist in the combination with hemoglobin control this operation. The more the amount of combined DPG with hemoglobin is, the less the tendency to intake oxygen will be, and vice versa, the less the amount of combined DPG with hemoglobin is , the more the tendency to intake oxygen will be. In the blood of small mammals like mouse, there is a lot of DPG. So, the tendency of their hemoglobin to combine with oxygen is less. While in the body of an elephant, the hemoglobin of the blood has more tendencies to combine with oxygen. Oxygen pressure at which, the hemoglobin gives, most of its oxygen to tissues, is 45mmHg for a mouse, 42mmHa for a rat which is larger than mouse, 38mmHg for a cat, 35mmHg for a fax, 30mmHg for a sheep, 25mmHg for a horse and 22.5mmHg for an elephant which is larger than all. That is in elephant's body the boxes on the train are opened gradually when the train passes through the villages, and the food remains until the train reaches at the highest village and the residents of that village receive food. In sheep's body the boxes are opened in large number at the villages, and the food finishes at the middle of the way and the residents of the upper villages do not receive food. In mouse's body all of the boxes are opened at the first village and the train is emptied very soon and it has to return. So, the course of the train is very short. So it becomes clear that, the nature can control the body the body size of the mammals by use of an organic phosphates beside the hemoglobin and keep some of them smaller in order to more probation. Of course, more propagation needs a lot of energy. Each cell of mouse's body consumes a lot of energy at the unit of time in compare with elephant cells. Because the train inside the body of the mouse empties all of its food at one village and it is clear that each resident of the village will receive a lot of food and so they will have enough food to have more activity. But in elephant's body the food is rationed and only a little food is given for each village, so that all the villages can receive food. For this reason each of the residents of elephant's body receives a little food, so they can not have more activity. Therefore the cells of elephant's body have low metabolism in compare with mouse's cells. As a result the growth and propagation in a mouse is by far more than an elephant. The heart of an elephant, which has 3 tons weight, beats 46puls/min and the heart of a mammal which has 70kg weight beats 76pulse/min. The heart of a cat which has 1.8kg beats 240pulse/min, and the heart of a mammal which has 100g weight, beats 800pulse/min. In heart of a mammal which beats 76pulse/min, the contraction of the ventricle lasts about 0.31s and after that, it rests for 0.49s. That is, the ventricle works 9.5h in 24h, and rests for about 14.5h. In heart of a mammal with faster pulsation, the period of rest is short but the numbers of pulsations are more. In a mammal whose heart beats very fast the contraction of the ventricle is 0.024s and the period of rest is 0.036s. So the ventricle works 9.5h a day and the remainder of ther day it rests. As we see the period of work and the period of the rest of the heart during a day, in large and small mammals is almost equal. So, the result is that, the strength of heart in mammals with different size is almost equal. When the body becomes larger the rate of heart becomes low and instead, its strength becomes more. When the body becomes smaller, the rate of the heart becomes faster, but instead its strength becomes less. But eventually, the whole energy and power of the heart remains fixed. This is like the changing of the automobile's gear. In an automobile the power of the engine is fixed. When the automobile moves with heavy gear, speed is low, but the power is high. When it moves with light gear, the speed is high but the power is low. In these two cases the power of the engine does not get more or less but, the gearwheels and levers change the energy to speed and force. Also in the heart of a mammal, such an action occurs. The capabilities of heart in all mammals are almost equal and only the rate of speed and force gets more and less.

Paper 13
Paper 14
Paper 15
Paper 16

Home page

ISBN 964-7061-4-8



1 1