The main dictate(s) of Lamarck's theory is/are
Lamarck incorporated two main postulates in his theory of evolution. The first was the idea of use and disuse of body parts or organs: he theorized that individuals lose characteristics that they do not require, over continuous disuse and develop characteristics that are useful. His second postulate was that these changes that occur in the organism, due to use or disuse, are inherited by the next generation, and offspring are born with that change. Furthermore, changes can occur in the lifetime of these offspring which are again passed onto their progeny and so on. Therefore, according to Lamarck, changes in the environment can act on both the genotype and phenotype of an organism.