Question

Write short notes based on Lamarckism.

Answer 1

Hint: Lamarckism is also known as Neo-Lamarckism and is the notion that an organism can pass physical characters to its offspring which are acquired by the parent organism through use or disuse during its lifecycle. This theory is known as the inheritance of acquired characteristics or soft inheritance.

Complete answer: The theory of Lamarckism is given by the French biologist Jean-Baptiste Lamarck as he incorporated the action of soft inheritance into the evolutionary theories as supplement to his concept of orthogenesis which is driven towards complexity. The theory of Lamarckism is the contrast with Darwinism. The studies like epigenetics, genetics and somatic hypermutation helped us to find possible inheritance of the traits which are acquired by the previous generations.

Lamarckism provided with the theory which involves the inheritance of the characteristics which are acquired by an individual in its lifetime. With the passage of time and development of the modern synthesis of theory of evolution but due to lack of evidence which demonstrate acquiring and passing on new characteristics or their heritability, theory of Lamarckism fell from favour. The scientists which feel that Lamarckism was key for the evolution of an organism were called neo-Lamarckianism. This theory of Lamarckism was supported by many scientists of that time but eventually Lamarckism theory was discarded from the evolution of an organism.

Note: Lmarck gave two ideas in the discussion of heredity. The first idea was the idea of use and disuse and the second was the idea that the acquired traits were heritable. These both ideas proposed by Lamarck were discarded when the modern evolution system was proposed.