The Paleontology ( ancient Greek παλαιός Palaios "old" ὤν ON , Gen. ὄντος ontos "being" and -logie ) is the science of living things and liver worlds of the geological past . The subject of paleontological research is fossils ( Latin fossilis "excavated"), that is, physical remains found in sedimentary rocks as well as other legacies and testimonies of living beings that are more than 10,000 years old.
The French zoologist and anatomist Henri de Blainville introduced the term palaeontology in 1825 , which gradually replaced the older terms oryctology (Greek ὀρυκτός oryktós "excavated") and petrefacts (Latin petrefactum "petrified").
The French natural scientist Georges Cuvier (1769–1832) is considered to be the founder of modern paleontology, which works according to scientific criteria . The British geologist Charles Lyell (1797–1875), who contributed to the theory of the ice age , disproved his view that catastrophes completely wiped out life on earth and that humans were only created after the last ice age. At the same time, the French amateur archaeologist Jacques Boucher de Perthes (1788–1868) was the first to recognize human creations in stone artifacts.
The French Marcellin Boule (1881–1942) created the possibility of distinguishing human tools from naturally created forms with his eolite experiment from 1905. The Swiss doctor Otto Hauser (1874–1932) made the professional introduction to cave and excavation research in France ( Le Moustier ) . There he encountered resistance from local research.
The first German paleontologist to represent Darwin's theory of descent was Ernst Haeckel (1834–1919). He was a zoologist and brought the development of humans to research through hominids. His opponent was Rudolf Virchow , who called him the "monkey professor". Haeckel's suggestions were taken up by the Dutch anatomist, geologist and military doctor Eugène Dubois (1858–1940) and the German paleontologist Gustav Heinrich Ralph von Koenigswald (1902–1982).
Since 1997, 21 palaeontology professorships have been given up in Germany, and eight of 27 university locations have been completely deleted.
- The paleozoology includes
- the paleontology of invertebrates , a sub-area is paleoentomology , the study of fossil insects.
- the vertebrate paleontology , it can in paleontology of fish ( Paläoichthyologie ) of amphibians and reptiles ( Paläoherpetologie ), the Birds ( paleornithology ) and that of mammals ( Paläomammalogie ) are divided.
- The Paläobotanik dedicated to the fossil plants and includes among others the palynology , the study of fossil pollen and spores .
The paleontology of macrofossils differs in its methodology from micropaleontology , which examines microfossils and the even smaller nannofossils with the aid of various microscopy techniques . Microfossils can be the remains of microorganisms as well as microscopic evidence of larger living things.
Paleontologists examine fossils and fossil groups of organisms from a variety of points of view and questions. A division into geologically and biologically oriented sub-areas is made:
- The theory of fossilization (taphonomy) describes the path from the death of an individual to the finished fossil . It also explains the formation of so-called fossil deposits , in which the remains of fossil living beings are particularly numerous ( concentrate deposits ) or particularly completely preserved ( preservation deposits ).
- The temporal classification and the relation (correlation) of sedimentary rock formations and their strata based on their fossil content is the subject of biostratigraphy . For this purpose, among other things, special key fossils are selected by the biostratigraphers .
- The biofacies analysis tries to characterize the formation area of a sedimentary rock based on its fossil organisms and traces of life.
- With the help of comparative anatomy , fossil living beings are classified in the system of organisms. The biological system is used.
- The phylogenetic studies the relationships of fossil organisms. She creates family trees ( dendrograms ). The tribal histories of fossil animal and plant groups have been increasingly analyzed since the 1980s with the help of so-called cladistics , a method that allows the degrees of kinship to be quantified .
- The functional morphology interprets the appearance of fossil living beings in terms of their function ( paleobiology ). Such analyzes are supplemented by references to the physical and biochemical life processes of fossil organisms, which paleophysiology is concerned with. Paleopathology (this term is also used in archeology when examining human remains) is the study of dysfunction and disease .
- The growth and development ( ontogenesis ) of primeval creatures are examined using animal skeletons ( sclerochronology ; bone histology ) or the shoot axes of fossil plants ( dendrochronology ). Growth rates as well as internal and external influencing factors that control the development of an individual can thereby be determined. The dendrochronology of young wood remains is used to determine the age of archaeological sites.
- The way of life of fossil organisms, their relationships to the animate and inanimate environment ( palaeoenvironment ) as well as primeval populations and communities are the subject of research in paleo- ecology . In order to understand prehistoric ecosystems , it is necessary to consider the sedimentology of fossil-bearing rocks.
- The paleobiogeography examines the change of the distribution areas and the migration routes of fossil organisms in the course of the earth's history . It provides information on earlier continent-ocean configurations (see also plate tectonics ) and their influence on the evolution of the biosphere .
Related branches of research
- The Geobiology is a research field that deals with the interactions between the biosphere and the abiotic deals components of the Earth system. Since indications of the change in the biosphere in the course of the earth's history are mainly available in the form of fossils, geobiological research is dependent on paleontological knowledge.
- The astrobiology explores the conditions under which on planetary simple worlds life forms, complex communities and civilizations arise. Paleontology can provide information about the origin of life on earth, the evolution of ecosystems under extreme environmental conditions, the diversification and higher development of life on earth and the biological-geological preconditions of human culture and civilization.
- Paleoclimatology : Reconstruction of (older) climate history is essentially using fossil creatures: in the carbonate skeletons of marine organisms (such as foraminifera ) are the oxygen - isotope ratios that prevailed in the primeval ocean at the time of skeletal deposition preserved. Since the isotope ratios set close to the surface depending on the water temperature, a temperature curve can be derived from the mass spectrometric measurements of these ratios. In addition to climate-indicative sediments such as moraine deposits or reef limestone , fossils also provide information on the previous location of climatic zones . So eco-zones can be traced with the help of plant (micro) fossils.
- The Paleogeography can to reconstruct the former location of continents and oceans, the geographical distribution of fossil creatures ( palaeobiogeography consult).
- The palaeochemistry deals u. a. with the chemical investigation of fossil finds.
- The Paleoanthropology deals with the human evolution . As part of anthropology, it is an auxiliary science of prehistory and early history and is taught as part of it.
The targeted search for fossils in a paleontological excavation is preceded by the geological mapping of the (presumably) fossil-bearing sedimentary rocks. The aim is to find new find points to clarify the situation of the already known horizons Fund to adjacent layers and rock units and the depositional environment sedimentological further characterize, were formed as whether sediments in a lake or a sea. Such an overview map is not necessary if the age, the stratigraphic classification and the lithology of the fossil-bearing rocks are already sufficiently known.
A systematic paleontological excavation is carried out layer by layer from the hanging wall , that is, starting with the youngest layer on top, to the lying , that is, in the direction of the older layers below. Accompanying the search for fossils, the geology of the stripped layers must be precisely described . The horizons are numbered consecutively. The numbering is transferred to the fossil finds so that they can be precisely assigned to the horizons.
If larger remains of organisms (such as dinosaur skeletons) are the target of the excavation, the position of individual bones and skeletal parts within a layer must be precisely documented with the aid of a grid laid over it. This is important to e.g. B. to reconstruct dying attitudes or deposition and transport processes and to distinguish bones of different individuals.
For the extraction of microfossils, rock samples are taken from the individual horizons and later processed in the laboratory.
Preparation and preparation
Crumbly fossil remains are glued on site or fixed with alcohol-soluble chemicals for later preparation . Plaster of paris may also be required to protect bone finds . If fossils are spread over several rock slabs, they are often stuck together again at the break point.
The later preparation of the fossils in the laboratory is mostly done mechanically, i.e. with a scalpel and dissecting needles (compressed air chisel / airtool) under a magnifying glass or using a stereomicroscope . With the help of X-rays , fossil parts hidden by the rock can be localized. Damage during preparation is avoided in this way.
Often microfossils can be removed from the rock with the help of acid etching or other wet chemical processes (see micropalaeontology ).
Documentation, description, classification
For the further analysis of the fossils it is important to use different methods, i. H. graphically, photographically and, if necessary, to make filigree structures visible with a scanning electron microscope .
The photographic and / or graphic documentation forms the basis for the description and interpretation of a fossil find and its systematic classification . A new taxon can also be named within this framework .
From the fossil drawing, the original skeletal context (in animals) or organ context (e.g. in plants) can be reconstructed, taking into account known specimens and / or representatives of related groups. A reconstruction of the life picture can then take place. Interpretations of the function, way of life and mode of locomotion of fossil living beings are incorporated. If necessary, the death process of the animal is also reconstructed.
Palecological evaluation of the terrain data
Since the fossil contents of all layers of the find are precisely documented , an analysis of the fauna and flora composition and then a reconstruction of the food web can take place in the event that the respective organism remains were not transported from different places of origin, but come from the same ecosystem . The sedimentological description provides additional information on the transport and deposition processes that led to the formation of the fossil-bearing rock.
Conversely, fossils provide geologists with information on the nature of the sedimentation space, for example if the predominant fossil groups only under very specific environmental conditions (e.g. on the sea floor in clear water at temperatures between 18 and 20 ° C and a salinity of <2.5%) occurred.
The vertical sequence of horizons corresponds to a temporal one: By comparing the communities of different horizons, conclusions can be drawn about the development history of a prehistoric ecosystem.
If the samples are large enough, that is, enough individuals of a species have been found and documented in a horizon, they can be examined as an equivalent to a natural population with regard to the variability of body characteristics. The composition of the ecosystem can also be recorded quantitatively (e.g. predator-prey ratios).
The chemistry of water bodies can influence the composition of skeletons and housings. Often times of the year and time of day fluctuations in the chemical and isotope composition can be recorded in accretionary growing hard parts . Some of these can be interpreted climatically (see also paleoclimatology ).
The microscopic analysis of thin sections made of bones or housings provides information on the growth and earlier tissue properties of the respective hard parts. They sometimes contain important clues about the physiology and ontogeny of the hard part creator.
If the skeletons are fully preserved, the movements of fossil animals can be simulated in the form of computer models. In this way, it is possible to rule out certain behavior and lifestyles or to accept them as likely.
Relationships and family trees of fossil groups of organisms are now mainly determined using computer-aided cladistics methods . Combinations of characteristics of the fossil species to be examined are compared with one another and family trees are calculated in the form of branching schemes ( cladograms ) based on the principle of economy. Accordingly, the results of these analyzes represent the presumed course of evolution under the assumption of as few evolutionary steps as possible.
Stratigraphic relationship (correlation)
All fossil species that a site produces occur in a certain relatively narrow geological period. If these species are also known from other localities, a possible common formation period of the different find layers follows.
The comparison of several sedimentary rock sequences containing certain fossils and volcanic rocks (such as tuffs ) that can be dated by geochronological methods enables the assignment of more accurate ages (i.e. those with lower margins of error).
- Michael J. Benton : Paleontology of the vertebrates . Publishing house Dr. Friedrich Pfeil, Munich 2007, ISBN 978-3-89937-072-0 .
- Michael J. Benton, David AT Harper: Basic Palaeontology. Pearson, Harlow 1997, ISBN 0-582-22857-3 .
- Patrick J. Brenchley, David AT Harper: Palaeoecology. Ecosystems, environments and evolution. Chapman & Hall, London 1998, ISBN 0-412-43450-4 .
- Zoë Lescaze: Paleo-Art. Representations of prehistory . Taschen, Cologne 2017, ISBN 978-3-8365-6584-4 . The publisher also published the same book in English, French and Spanish.
- Jörg Mutterlose, Bernhard Ziegler: Introduction to Paleobiology I: General Paleontology. 6th revised and supplemented edition. Schweizerbart, Stuttgart 2018, ISBN 978-3-510-65415-4 .
- Arno Hermann Müller: Textbook of paleozoology. Volume 1: General Basics. 5th edition. Fischer, Jena 1992, ISBN 3-334-60378-4 .
- Hans D. Pflug: The trace of life - paleontology viewed chemically. Springer, Berlin 1984, ISBN 0-387-13465-4 .
- Derek Turner: Paleontology: A Philosophical Introduction. Cambridge University Press 2011, ISBN 978-0-521-13332-6 , Alan C. Love: Review , Notre Dame Philosophical Reviews (NDPR) December 18, 2011.
- Introduction to Paleontology - Website of the Austrian Paleontological Society
- Geology, Palaeontology and Geobiology for Students, Teachers and Everybody - Interesting facts about palaeontology and closely related geosciences (domain operated by Reihold Leinfelder, currently hosted on the server of the FU Berlin; partly German, partly English)
- Teaching Documents about Palaeontology and Palaeoecology - List of links to websites, web pages of media platforms and literature (recommendations) on the subject of palaeontology (English)
- The Paleobiology Database - Scientific database, which aims to record the fossil record of animals and plants as completely as possible (English)