Both the theories of conservative and semi-conservative mode of replication were proposed basically to explain the mode of deoxyribonucleic acid (DNA) replication. According to the conservative mode of replication, the two strands of the DNA of the parents would remain as such and two new strands that would be formed as a result of replication would pair up forming the daughter DNA helix. This model was not found to be correct.
As opposed to the conservative mode of replication, in semi-conservative mode of replication, each of the two parent strand would be used as a template for the new strands to be developed. These new strands developed would be complementary to the older ones and would be paired oppositely through the hydrogen bonds. Thus, in a semi-conservative mode of replication, there would be one new strand and one old strand in a single helix. This was the model that was proven correct on the basis of practical experiments.