The propositions of Lamarckism were as follows:-
Inheritance of Acquired Characters: Whatever character an individual acquires in its lifetime due to internal vital force or effect of environment or new needs and use and disuse of organs; they are transmitted to the next generation.
Internal Vital Force: All the living things and their component parts continually increase due to internal vital force.
Effect of Environment and New Needs: Environment influences all types of organisms. A change in environment brings about changes in organisms. It gives rise to new needs.
Use and Disuse of Organs: If an organ is constantly used it would be better developed whereas disuse of organ results in its degeneration.