Many organic skeletons act as maximum thermometer s when heated, with irreversible physical and chemical changes that provide measurements of the temperature history of their host rocks. On the applied side, most paleontologists are hired by consultants and by companies in the petroleum industry. This is because the origin, time of formation and distribution of oil, involves detailed knowledge of biostratigraphy and ancient environ ments. Paleontologists identify fossils for use in stratigraphy, in studying sedimentary processes and in the study of temperature alterations of sediments. Most paleontologists with doctoral degrees are found in universities, consulting companies, federa l and provincial surveys, and working in museums.
Paleontologists normally specialise in the four following areas.
Inver tebrates and microfossils are most abundantly represented in the fossil record. They are most widely used for dating rocks and therefore most useful in geological applications. Many vertebrate paleontologists and paleobotanists graduate from biology progr ammes or through combined geology-biology majors. A four-year undergraduate programme followed by a M.Sc. degree is the minimum requirement for paleontology. Students would normally take courses in sedimentology and stratigraphy and some programmes would enable the student to take specialised pale ontology courses at a more advanced level, for example, in micropaleontology.