Ecological genetics is the study of genetics on an ecological scale. While molecular genetics studies the structure and function of genes at a molecular level, ecological genetics (and the related field of population genetics) studies wild populations of organisms.
Studies are often done on insects and other organisms that have short generation times, and thus evolve at fast rates.
Although work on natural populations had been done previously, it is acknowledged that the field was founded by the Briton E.B. Ford in the early 20th century. Ecological Genetics is the title of his 1964 'magnum opus' on the subject. Other notable ecological geneticists would include Theodosius Dobzhansky's work on Hawaiian fruit flies. Ford's genetics school at Oxford in the 1960s is famous for studies, including Bernard Kettlewell's work on the peppered moth.
However, obtaining enough data on natural populations was difficult, as was obtaining research grants for long-term projects. As a result, funding was diverted towards molecular genetics. Improved understanding of molecular genetics however, allowed the development of improved biochemical techniques during the 1980s and 1990s which in turn allowed data on natural populations to be derived.