Tag: darwin's theory of evolution

Lamarck was French naturalist who proposed the theory of individual acquire characters to explain the process of natural selection. According to the inheritance of acquired characters, individual acquire characters under influence of needs as posed as changing environmental conditions; these characters are inherited. He explained evolution the long-necked giraffes from short-necked giraffes on the basis of his theory. Thus, the correct answer is option B.

Lamarck is best known for his, 'Theory of Inheritance of Acquired Characteristics', first presented in 1801 (Darwin's first book dealing with natural selection was published in 1859): If an organism changes during life in order to adapt to its environment, those changes are passed on to its offspring. He said that change is made by what the organisms want or need. For example- Lamarck believed that elephants all used to have short trunks. When there was no food or water that they could reach with their short trunks, they stretched their trunks to reach the water and branches, and their offspring inherited long trunks. Lamarck also said that body parts that are not being used, such as the human appendix and little toes are gradually disappearing. Eventually, people will be born without these parts. Lamarck also believed that evolution happens according to a predetermined plan and that the results have already been decided.

Philosophie zoologique is an 1809 book by Jean-Baptiste Lamarck in which he outlines his theory of evolution now known as Lamarckism. In the book, Lamarck named two supposed laws that would enable animal species to acquire characteristics under the influence of their environment. The two laws are as followed :

Lamarck has suggested the theory of use and disuse of organs. According to this theory, if any organ is used to its maximum optimum levels it's size increases gradually because of it's repeated use. On the contrary, the size of organs that are used goes on reducing considerably. This is because of their constant disuse. 

The snakes have been evolved from lizard like ancestors, which were having two pairs of limbs and there is absence of limbs in snakes, it is explained by Lamarckism.

the famous theory of acquired characters was put forward by Lamarck. Lamarck suggested that if any changes take place in the life of organisms, that changes lead to change in their genetic character. This happens so that the organism can adapt better to their environment. These changes or adaptations are then passed on to subsequent generations. Thus they acquire these characters too.