tailieunhanh - Teaching About Evolution and the Nature of Science - NAP (2004) Episode 8

Tham khảo tài liệu 'teaching about evolution and the nature of science - nap (2004) episode 8', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | http catalog 96 Teaching About_ Evolution and the Nature of Science Student Sheet Zoological Philosophy Jean Lamarck 1809 The environment affects the shape and organization of animals that is to say that when the environment becomes very different it produces in course of time corresponding modifications in the 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. 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 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