Molecular ecology is a recently developed discipline in biology. During the midtwentieth century, ecology and molecular biology occupied almost opposite positions in biological studies. Molecular biology is the study of organisms at the molecular level mainly for DNA, RNA and proteins. The disconnection between ecology and molecular biology may have been due to the differences in the size of objects being studied and investigative procedures. Molecular biologists seldom studied individual organisms in the field and most ecologists were not aware of DNA in their studies; however, the improvement of molecular techniques and advances in theoretical studies in evolutionary ecology and population genetics enable both disciplines to be combined.