Molecular evolution is the study of how biological molecules, particularly DNA, RNA, and proteins, change over time through processes like mutation, selection, and genetic drift. These changes can lead to variations within species and contribute to the development of new species. By analyzing these molecular changes, scientists can trace the evolutionary history of organisms and understand their relationships. Researchers use techniques such as comparative genomics and phylogenetics to examine the genetic sequences of different organisms. This helps in identifying common ancestors and understanding how specific traits have evolved. Molecular evolution provides insights into the mechanisms of evolution at a molecular level, enhancing our knowledge of biology and genetics.