Paleontology has its roots in biology and geology. It deals with the remains of living organisms from past geological eras (fossils) and their application to such diverse questions as determining the age of rock layers, evolution and biodiversity research, the biology of extinct groups of organisms, as well as climate research and the reconstruction of habitats and deposits. But it is also used in practice, e.g. in the exploration of hydrocarbons and other raw materials or in geological mapping.