Lamarck's theory (theory of acquired characters). Lakarckism includes the fourmain factors

$(i)$ Internal Vital Force All the living things and their component parts are continually increased due to the internal vital force

$(ii)$ Effect of Environment and New Needs Environment influences all the type of organisms. Any changes in environment brings about changes in organisms. It gives rise to the new needs of organisms

$(iii)$ Use and Disuse of Organs If an organ is constantly used it would be better developed whereas disuse of organ results in its degeneration

$(iv)$ Inheritance of Acquired Characters Whatever an individual acquires (to possess) characters in its life time due to internal vital forces effect of environment, new needs and use and disuse of organs, they are inherited (transmitted) to the next generations. After several generations, the variations are accumulated upto such extent that they give rise to new species

Objection in Lamarck Theory

$(i)$ Boring of pinna (external ear) and nose of women is never inherited to the next generations

$(ii)$ The wrestler's powerful muscles are not transmitted to the offspring

$(iii)$ European ladies wear tight waist garments in order to keep their waist slender but their off spring at the time of birth have normal waists

$(iv)$ Chinese women used to wear irons shoes in order to have small feet, but their children at the time of birth have always normal feet