The integration of ecology and genetics. Of main interest are the parameters that determine the function of genes at the intra-individual molecular level through to the level of ecosystem functioning and resilience. Ecological genetics considers diverse factors such as geology, climate, chemistry, physics, along with interactions among living organisms and the environments they inhabit. One unifying characteristic of living organisms is the presence of nucleic acid in cells. Information encoded in nucleic acid sequences (DNA) provides insight into the evolutionary history, or phylogeny, of natural populations. Ecological genetics uses a statistical framework for understanding origins and patterns of Earth's biodiversity. It investigates forces of diversification, adaptation, migration, and extinction in the context of the known scientific history of Earth and of human beings.