The Path to the Chromosome Theory of Heredity :: History Science Biology Essays

The Path to the Chromosome Theory of genetic endowment The notion of the chromosome theory of heredity is very important to the understanding of growing and genetics. There were many ideas, some correct and others not, which influenced the revolutionary discovery of chromosomal heredity. The main stones in the path to the chromosomal theory are the pangenesis hypothesis, the germ-plasm theory, and Mendels Laws.PangenesisLamarck expressed the idea that by simply using or not using certain organs they may be developed or atrophied and their offspring can then inherit these acquired characteristics. (Milner p. 375, 1993) It should be say that this theory was not widely accepted largely due to the situation that the French word that Lamarck used in the sense of must was translated as wants to, which makes it sound as though the organism decides to change its body. Further more, Lamarck provided no instrument by which this could take place. (www.ridgenet.net/do_while/sage/v1i8f.ht m) Darwin was the one to give a mechanism for Lamarcks idea. This mechanism is known as pangenesis.Darwins ideas of evolution were healthful founded in the beginning however, as his theory progressed he reverted to Lamarckian mind to explain his observations. To begin his theory he started with the observations that there is variation in offspring. He wrote, no one supposes that any the individuals of the same species inhabiting the same contain locality, are cast of the same moldI am convinced that the most experienced naturalist would be surprised at the good turn of the cases of variabilityas I have collected (Chapter 2 of strain of Species). He sees that there is a struggle for existence saying, as more individuals are produced than can possibly survive, there must in all case be a struggle for existence (Chapter 3 of downslope of Species). Finally, Darwin recognized that there is a survival of the fittest in that the organisms with the best variations for the s equel of the species live and those with variations that are not as useful to the continuation of the species break dance (Chapter 4 of Origin of Species). Darwin begins to diverge into Lamarckian thought at this point. Darwin wrote that, fairly different changes in the conditions of flavor add to the vigor and fertility of all organic beingsthe crossing of forms which have been exposed to slightly different conditions of life or which have varied, favours the size, vigor, and fertility of their offspring (Chapter 9 of Origin of Species).