The origin of life refers to the time period in Earth's history before the appearance of the first forms of life. Its study is an interdisciplinary scientific field, ranging from the geological to the biophysical. It is concerned with the biological and physical processes that brought about the formation of the first living systems from non-living matter. Current scientific understanding suggests that this occurred as a complex network of chemical reactions, sometime in the range of 4.2 – 3.8 billion years ago. It remains one of the fundamental questions in the field of astrobiology.

See also: abiogenesis, evolutionary psychology, emergence, cambrian explosion, evolution