Zoological Philosophy by Jean-Baptiste Lamarck The environment affects the shape
ID: 212325 • Letter: Z
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Zoological Philosophy by Jean-Baptiste Lamarck The environment affects the shape and organization of animals, that is to say that when the he vironment becomes very different, it produces in course of time corresponding modifications in t shape and organization of animals. If a new environment, which has become permanent for some race of animals, induces new habits in these animals, that is to say, leads them into new activities which become habitual, the result will be the use of some one part in preference to some other part, and in some cases the total disuse of some part no longer necessary 2. Nothing of all this can be considered as hypothesis or private opinion; on the contrary, they are truths which, in order to be made clear, only require attention and the observation of facts. Snakes have adopted the habit of crawling on the ground and hiding in the grass; so that their body, as a result of continually repeated efforts at elongation for the purpose of passing through narrow spaces, has acquired a considerable length, quite out of proportion to its size. Now, legs would have been quite useless to these animals and consequently unused. Long legs would have interfered with their need of crawling, and very short legs would have been incapable of moving their body, since they could only have had four. The disuse of these parts thus became permanent in the various races of these animals, and resulted in the complete disappearance of these same parts, although legs really belong to the plan or organization of the animals of this class. The frequent use of any organ, when confirmed by habit, increases the functions of that organ, leads to its development, and endows it with a size and power that it does not possess in animals which 3. exercise it less. We have seen that the disuse of any organ modifies, reduces, and finally extinguishes it. I shall now prove that the constant use of any organ, accompanied by efforts to get the most out of it, strengthens and enlarges that organ, or creates new ones to carry on the functions that have become necessary 4. The bird which is drawn to the water by its need of finding there the prey on which it lives, separates digits at their base acquires the habit of being stretched by these continually repeated digits of its feet in trying to strike the water and move about on the surface. The skin which unites these separations of the digits; thus in course of time there are formed large webs which unite the digits of peculiar shape and size of the giraffe; this animal, the largest of the mammals, is known to live in the maintained in all its race, it has resulted that the animal's fore-legs have become longer than its hind se, etc. as we actually find them. It is interesting to observe the result of habit in the interior of Africa in places where the soil is nearly always arid and barren, so that it is obliged to browse on the leaves of trees and to make constant efforts to reach them. From this habit long egs, and that its neck is lengthened to such a degree that the giraffe, without standing up on its hind legs, attains a height of six meters (nearly twenty feet). Philosophic Zoologique. Paris 1809. Translated by H. Elliott, Macmillan Company, London 1914. What is the role of the environment in Lamarck's explanation? What scientific approach is suggested by Lamarck's statement: "Nothing of all this can be considered as hypothesis or private opinion; on the contrary, they are truths which, in order to be made clear, only require attention and the observation of facts Was Lamarck's explanation scientific? Why or why not? Can you propose any other explanations for Lamarck's observations about the disuse and use of organs?Explanation / Answer
lamarck gave lamarkism that talks about heritability of acquired characteristics,the idea was the use and the organs which are not use according to the circumstances like snakes thaey are belived to be evolved in sea but later on they come to the dry land where fins are not in use and with the passing time they loose there fins and few organs in human body(appendix) are example of it. simply the individual loose the characteristics which are not in use, the aquired traits are inharitable.
it is hypothesis,
at first the human body was well covered with hairs but now you can see less hairs on the human body as compare to the monkey.
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