LAMARCKISMAND NEO-LAMARCKISM.When seeing the history of evolution, the first personto propose theories about it was Jean Baptiste Lamarck.
He in his book philosophie zoologique, proposed thefollowing,1. Allorganisms will tend to grow or increase in size2. Neworgans will be developed when there is a need.3.
Theorgans that are constantly used will increase in size and the organs that arenot used will degenerate (use and disuse theory)4. Thecharacters that are acquired by the organism in its life time will be inheritedin the forthcoming generations.He also quoted examples for all his theories and hencehe gained many supported. The basis of his theory was, whenever the environmentchanged, there was an urge within the animal to adopt to the environment andhence it developed new characters or organs. The obtainedtrait was passes on to the next generations. his first two law were notobjected, but many criticised the 3rd and 4th laws.Scientists said that ear piercing, circumcision, exercising and developingmuscle and getting scars during the life time are acquired characters. But, theoffspring are not found to be born with those character.
August Weismanndisproved Lamarck’s idea of inheriting acquired character by cutting the tailof white mice for several generations and mating them. But, all the offspringwere born with tail. Hence, he concluded that changes that occur in the gameticcells are inherited and not those changes that happen in the somatic cells.Lamarck also failed to explain about the evolutionary aspect of speciation.But Lamarck’s effort to relate fossils and theadaptation of organisms was welcomed by many scientists and he gained many supporters.They were called as Neo-Lamarckian. They also proposed many theories to supportLamarck. Some of them are · Alpheus Spring Packard – said that cave dwellinganimals don’t need to see, hence their eyes degenerated.
· Edward drinker cope- said that fossilrecords were well explained by Lamarck than by Darwin· Ernts Haeckel, Theodor Eimer, Samuel butleralso supported Lamarck.· Michurin, Lysenko also worked with theacclimatization of plants in varied climate and said that the resistanceacquired in the cytoplasm was transferred through generations.· The experiments done by Charles-Édouard Brownand Gaston Bonnier to support Lamarckism were also opposed and rejected.Thus, neo-Lamarckian theories were considered to beloose without any cohesion and concrete basis. But the experiment by Gustav Tornierin gold fish and the embryo of frog and William Lawrence in potato beetle areserving as evidenced for the inheritance of acquired character. Thus, theLamarck’s theory cannot be completely objected as the recent genetic studiesreveal that both germplasm and somatoplasm are needed for a character to appearand get transferred.