Paleontology is the study of prehistoric life, including aspects as diverse as the fossil record, the history of Earth’s climate and the relatedness of DNA. It also has relevance for astrobiology and the possible development of life outside the Earth. Each of these disciplines is a separate branch of paleontology. Based on reporting self-identification, the American Geological Institute (AGI) identifies 11 different specialty codes of paleontology.
Although the AGI records have separate specialty codes for geobiology and paleobiology, they are the same branch of paleontology. Geobiologists study the interactions between the biosphere and the non-living world. This broad branch of paleontology spans the gap between geology and biology.
These three branches of paleontology study fossil records. As their names suggest, invertebrate paleontologists focus on the fossils of invertebrates, while vertebrate paleontologists specialize in the fossils of primitive fish, reptiles, and all other vertebrates, including dinosaurs. In general, micropaleontologists study the fossils of microscopic organisms, regardless of their exact taxonomy.
A related area of study, taphonomy, is sometimes listed as a separate branch of paleontology. Taphonomy is the study of decay, preservation and the formation of fossils. Although a specialization in human paleontology is also possible, this branch of study is more commonly classified under anthropology.
This branch of paleontology also studies the fossil record, this time with a specialization in fossil plants. It also includes the study of larger fossil algae and fungi. However, the study of fossil cyanobacteria (blue-green algae) and other microscopic algae and fungi is usually included under micropaleontology.
Paleoecology and paleoclimatology
These paleolontogists specialize in the ecology and climate of the distant past. The environmental and climate change debates have ensured that these directions of research are the hottest trends in paleontology today.
Based on self-reporting at the time of writing, the 2 divisions are still grouped together by the AGI. This represents the state of the field roughly a decade ago, when these professional paleontologists would have completed their educations. However, the rapid expansion and breadth of the field has ensured that each division is becoming a distinct branch of paleontology in its own right.
Paleoecologists focus on ecosystems and the interactions between different organisms during different periods in the Earth’s history. Special attention is often given to the oxygenation of the Earth’s atmosphere and various subsequent oxygen crisis events, especially as that information may apply to possible future oxygen crisis events.
Paleoclimatologists concentrate on the history of Earth’s climate. The current emphasis of most paleoclimatological research is on how climate has been influenced by changes in the Earth’s biosphere.
Also known as biostratigraphy, this branch of paleontology correlates the fossil record with the relative ages of rock strata, which establishes overall chronology and dating horizons for use in other fields of study. This is still the branch of paleontology which is most employed by the gas and oil industry, although the commercial need for paleostratigraphers is much lower today than it used to be.
Palynologists study the organic and inorganic contents of dust, including living and fossil pollen and spores. The contents and classification of dust, correlated against the location from which the dust sample was obtained, can give clues about the earliest life forms on land and the conditions under which they lived.
This branch of paleontology represents the practical application of quantitative analysis to paleolotogical methods. It is the cross-disciplinary study where analytical mathematics and paleontology meet.
A few paleontologists self-identify as general paleontologists. Generalists are most likely to work in museums or as the lone paleontologist on an otherwise geologically-oriented team.