(from Greek: παλαιό (palaio)
, "old, ancient"; όν (on)
, "being"; and logos
, "speech, thought") is the study of prehistoric
life forms on Earth through the examination of fossils
. This includes the study of body fossils
, tracks (ichnites
, cast-off parts, fossilised faeces
and chemical residues.
Modern paleontology sets ancient life in its context by studying how long-term physical changes of global geography paleogeography and climate paleoclimate have affected the evolution of life, how ecosystems have responded to these changes and have adapted the planetary environment in turn and how these mutual responses have affected today's patterns of biodiversity. Hence, paleontology overlaps with geology (the study of rocks and rock formations) as well as with botany, biology, zoology and ecology – fields concerned with life forms and how they interact.
The major subdivisions of paleontology include paleozoology (animals), paleobotany (plants) and micropaleontology (microfossils). Paleozoologists may specialise in invertebrate paleontology, which deals with animals without backbones or in vertebrate paleontology, dealing with fossils of animals with backbones, including fossil hominids (paleoanthropology). Micropaleontologists study microscopic fossils, including organic-walled microfossils whose study is called palynology.
There are many developing specialties such as paleobiology, paleoecology, ichnology (the study of tracks and burrows) and taphonomy (the study of what happens to organisms after they expire). Major areas of study include the correlation of rock strata with their geologic ages and the study of evolution of lifeforms.