Difference between revisions of "Paleobotany" - New World Encyclopedia
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[[Angiosperms]] ([[flowering plants]]) evolved during the [[Mesozoic]], and flowering plant pollen and leaves first appear during the Early [[Cretaceous]], approximately 130 million years ago. | [[Angiosperms]] ([[flowering plants]]) evolved during the [[Mesozoic]], and flowering plant pollen and leaves first appear during the Early [[Cretaceous]], approximately 130 million years ago. | ||
| + | '''Palynology''' is the science that studies contemporary and fossil [[palynomorph]]s, including [[pollen]], [[spores]], [[dinoflagellate]] [[cyst]]s, [[acritarchs]], [[chitinozoa]]ns and [[Scolecodonts|scolecodont]]s, together with particulate organic matter (POM) and [[kerogen]] found in [[sedimentary]] rocks and [[sediment]]s. | ||
| + | |||
| + | The term ''palynology'' was introduced by Hyde and Williams in [[1944]], following correspondence with the Swedish [[geologist]] Antevs, in the pages of the Pollen Analysis Circular (one of the first journals devoted to pollen analysis, and produced by Paul Sears in North America). Hyde and Williams chose ''palynology'' on the basis of the [[Greek language|Greek]] words ''paluno'' meaning to sprinkle, and ''pale'' meaning dust (and thus similar to the [[Latin]] word ''pollen''). | ||
| + | |||
| + | ==Paleoecology== | ||
| + | '''Paleoecology''' uses data from [[fossil]]s and subfossils to reconstruct the [[ecosystem]]s of the past. It includes the study of [[fossil]] organisms in terms of their [[life cycle]], their living interactions, their [[natural environment]], their manner of [[death]] and burial. '''Paleoecology''''s aim is therefore to build the most detailed model possible of the [[Ecology|life environment]] of those [[Biology|living organisms]] we find today as fossils; such reconstruction work involves complex interactions among environmental factors ([[temperature]], [[food]] supplies, degree of [[Sun|solar illumination]], etc.). Of course, much of this complex data has been distorted or destroyed by the post-mortem fossilization processes, adding another layer of complexity. | ||
| + | |||
| + | The environmental complexity factor is normally tackled through [[statistics|statistical]] analysis of the available numerical data (quantitative [[paleontology]] or [[paleostatistics]]), while post-mortem processes as a source of information are known as the field of taphonomy. | ||
| + | |||
| + | Much '''paleoecological''' research focuses on the last two million years (formerly known as the [[Quarternary]] period) because older environments are less well-represented in the fossil [[timeline of evolution]]. Indeed, many studies concentrate on the [[Holocene]] epoch (the last 10,000 years), or the last glacial stage of the [[Pleistocene]] epoch (the [[Wisconsin glaciation|Wisconsin/Weichsel/Devensian/Würm glaciation]] of the [[ice age]], from 50,000 to 10,000 years ago). Such studies are useful for understanding the dynamics of [[ecosystem]] change and for reconstructing pre-industrialization [[ecosystem]]s. Many [[public policy]] decision-makers have pointed to the importance of using paleoecological studies as a basis for choices made in [[conservation ecology]]. Often paleoecologists will use cores from lakes or bogs to reconstruct [[pollen]] assemblages, lithology, and to perform geochemical analysis. These tools aid in determining the species composition and climatic conditions, which can contribute to our understanding of how ecosystems change and have changed with climatic and environmental conditions. | ||
| + | |||
| + | ==Palynology== | ||
| + | Palynology is a branch of [[earth science]] ([[geology]] or geological science) and biological science ([[biology]]), particularly plant science ([[botany]]). [[stratigraphy|Stratigraphical]] palynology is a branch of [[micropaleontology|micropalaeontology]] and [[paleobotany]] which studies [[fossil]] palynomorphs from the [[Precambrian]] to the [[Holocene]]. | ||
| + | |||
| + | === Methods of study === | ||
| + | Palynomorphs are broadly defined as organic-walled [[microfossil|microfossils]] between 5 and 500 [[micrometre]]s in size. They are extracted from rocks and sediments both physically, by wet sieving, often after ultrasonic treatment, and chemically, by using chemical digestion to remove the non-organic fraction. For example, palynomorphs may be extracted using [[hydrochloric acid]] (HCl) to digest [[carbonate]] minerals, and [[hydrofluoric acid]] (HF) to digest [[silicate]] [[mineral|minerals]] in suitable fume cupboards in specialist laboratories. | ||
| + | |||
| + | Samples are then mounted on [[microscope]] slides and examined using light [[microscopy]] or [[SEM|scanning electron microscopy]]. Once the pollen grains have been identified they can be plotted on a pollen diagram which is then used for interpretation. Pollen diagrams are useful in giving evidence of past human activity (anthropogenic impact), vegetation history and climatic history. | ||
| + | |||
| + | Palynology uses many techniques from other related fields such as [[geology]], [[botany]], [[paleontology]], [[archaeology]], [[pedology (soil study)|pedology]], and [[geography]]. | ||
| + | |||
| + | === Applications === | ||
| + | Palynology is used for a diverse range of applications, related to many scientific disciplines: | ||
| + | |||
| + | * [[Biostratigraphy]] and [[geochronology]]. Geologists use palynological studies in biostratigraphy to correlate [[stratum|strata]] and determine the relative age of a given bed, horizon, formation or [[stratigraphy|stratigraphical]] sequence. | ||
| + | * [[paleoecology|Palaeoecology]] and [[climate change]]. Palynology can be used to reconstruct past [[vegetation]] (land plants) and [[ocean|marine]] and [[freshwater]] [[phytoplankton]] communities, and so infer past [[natural environment|environmental]] ([[paleoenvironment|palaeoenvironment]]al) and [[(palaeoclimate|palaeoclimatic]] conditions. | ||
| + | * [[organic compound|Organic]] palynofacies studies, which examine the preservation of the particulate organic matter and palynomorphs provides information on the depositional environment of sediments and depositional palaeoenvironments of [[sedimentary|sedimentary rocks]]. | ||
| + | * [[Geothermal alteration]] studies examine the [[color]] of [[palynomorph]]s extracted from rocks to give the thermal alteration and [[hydrocarbon|maturation]] of [[sedimentary]] sequences, which provides estimates of maximum [[paleotemperatures|palaeotemperatures]]. | ||
| + | * [[Limnology]] studies. Freshwater [[palynomorphs]] and animal and plant fragments, including the [[prasinophyte]]s and [[desmid]]s ([[green alga]]e) can be used to study past lake levels and long term [[climate change]]. | ||
| + | * [[scientific classification|Taxonomy]] and [[evolution|evolutionary studies]]. | ||
| + | * [[Forensic palynology]]- the study of [[pollen]] and other [[palynomorph]]s for evidence at a crime scene. | ||
| + | * [[Allergy]] studies. Studies of the geographic distribution and seasonal production of pollen, can help sufferers of allergies such as [[hay fever]]. | ||
| + | * Melissopalynology - the study of pollen and spores found in honey. | ||
| + | |||
| + | Because the distribution of acritarchs, chitinozoans, [[dinoflagellate]] cysts, [[pollen]] and [[spore]]s provides evidence of [[stratigraphy|stratigraphical correlation]] through [[biostratigraphy]] and [[palaeoenvironment]]al reconstruction, one common and lucrative application of palynology is in [[petroleum|oil]] and [[Natural gas|gas]] exploration. | ||
| + | |||
| + | Palynology also allows scientists to infer the climatic conditions from the vegetation present in an area [[geologic timescale|thousands or millions of years]] ago. This is a fundamental part of research into [climate change. | ||
| + | |||
| + | Literature] | ||
| + | |||
==Notable Paleobotanists== | ==Notable Paleobotanists== | ||
*[[Kaspar Maria von Sternberg]], the "father of paleobotany". | *[[Kaspar Maria von Sternberg]], the "father of paleobotany". | ||
| − | == | + | ==References== |
| − | Stewart, W.N. and Rothwell, G.W. 1993. ''Paleobotany and the evolution of plants'', Second edition. Cambridge University Press, Cambridge, UK. ISBN 0-521-38294-7 | + | * Brigitte Meyer-Berthaud, S.E. Scheckler, J. Wendt, "''Archaeopteris'' is the Earliest Modern Tree." ''Nature'', '''398''', 700-701 (22 April 1999) | doi:10.1038/19516 |
| + | * Charles H. Wellman, Peter L. Osterloff and Uzma Mohiuddin, "Fragments of the Earliest Land Plants." ''Nature'', '''425''', 282-285 (18 September 2003) | doi: 10.1038/nature01884 | ||
| + | |||
| + | *Kapp, R.O., Davis, O.K., King, J.E. 2000. ''Guide to Pollen and Spores.'' (Second edition). American Association of Stratigraphic Palynologists. ISBN 0931871050 | ||
| + | *Moore, P.D., et al. 1991. ''Pollen Analysis'' (Second Edition). Blackwell Scientific Publications. ISBN 0632021764 | ||
| + | |||
| + | *Stewart, W.N. and Rothwell, G.W. 1993. ''Paleobotany and the evolution of plants'', Second edition. Cambridge University Press, Cambridge, UK. ISBN 0-521-38294-7 | ||
| + | |||
| + | *Taylor, T. N. and E. L. Taylor. 1993. ''The Biology and Evolution of Fossil Plants'', Prentice-Hall, Inc., Englewood Cliffs, New Jersey, USA. ISBN 0-13-651589-4 | ||
| − | + | *Traverse, A. .1988. ''Paleopalynology''. Unwin Hyman ISBN 0045610010 | |
| − | ==External links== | + | == External links == |
| + | * [http://www.geo.arizona.edu/palynology/ifps.html International Federation of Palynological Societies] | ||
| + | * [http://www.palynology.org American Association of Stratigraphic Palynologists, Inc. (AASP)] | ||
| + | * [http://www.shef.ac.uk/uni/academic/N-Q/palysc/index.html Centre for Palynology, University of Sheffield, UK] | ||
| + | *[http://www.ifpindia.org/Palaeoenvironments-in-South-India.html Palynology Laboratory, French Institute of Pondicherry, India] | ||
| + | * [http://www.rbgkew.org.uk/scihort/palyn.html The Palynology Unit, Kew Gardens, UK] | ||
| + | * [http://www.paldat.org/ PalDat, palynological database hosted by the University of Vienna, Austria] | ||
| + | * [http://www.nhm.ac.uk/hosted_sites/tms/ The Micropalaeontological Society] | ||
| + | * [http://www.palynology.org/ The American Association of Stratigraphic Palynologists (AASP)] | ||
| + | * [http://www.shef.ac.uk/~cidmdp/ Commission Internationale de Microflore du Paléozoique (CIMP)], international commission for Palaeozoic palynology. | ||
| + | * [http://www.shef.ac.uk/~cidmdp/cimpsuba.html CIMP Subcommission on Acritarchs] | ||
| + | * [http://www.shef.ac.uk/~cidmdp/cimpsubc.html CIMP Chitinozoan Subcommission] | ||
| + | * [http://www.linnean.org Linnean Society Palynology Specialist Group (LSPSG)] | ||
| + | * [http://www.scirpus.ca/cap/cap.shtml Canadian Association of Palynologists] | ||
| + | * [http://www.geo.arizona.edu/palynology/polident.html Pollen and Spore Identification | ||
* [http://iop.biodiversity.org.uk/ International Organisation of Paleobotany] | * [http://iop.biodiversity.org.uk/ International Organisation of Paleobotany] | ||
* [http://www.uni-muenster.de/GeoPalaeontologie/Palaeo/Palbot/ebot.html Paleobotany Research Group, University Münster, Germany.] | * [http://www.uni-muenster.de/GeoPalaeontologie/Palaeo/Palbot/ebot.html Paleobotany Research Group, University Münster, Germany.] | ||
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* [http://www.nhm.ac.uk/paleonet/ PaleoNet - listservs and links related to paleontology] | * [http://www.nhm.ac.uk/paleonet/ PaleoNet - listservs and links related to paleontology] | ||
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{{credit|50711573}} | {{credit|50711573}} | ||
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[[Category:Life sciences]] | [[Category:Life sciences]] | ||
Revision as of 18:59, 26 July 2006
Paleobotany (from the Greek words paleon = old and botanikos = of herbs) is the branch of paleontology dealing with the recovery and identification of plant remains from geological contexts, and their use in the reconstruction of past environments and the history of life. A closely related field is palynology, the study of fossil and extant spores and pollen. Paleobotany includes the study of terrestrial plant fossils as well as the study of marine autotrophs, such as algae.
Paleobotany is important in the reconstruction of prehistoric ecological systems and climate, known as paleoecology and paleoclimatology respectively, and is fundamental to the study of plant development and evolution. Paleobotany has also become important to the field of archaeology, primarily for the use of phytoliths in relative dating and in paleoethnobotany,
Overview of the Paleobotanical Record
Macroscopic remains of true vascular plants are first found in the fossil record during the Silurian Period. Some dispersed, fragmentary fossils of disputed affinity, primarily spores and cuticles, have been found in rocks from the Ordovician Period of Oman and are thought to derive from liverwort- or moss-grade fossil plants (Wellman et. al., 2003).
An important early land plant fossil locality is the Rhynie Chert, an Early Devonian sinter (hot spring) deposit composed primarily of silica found outside the town of Rhynie in Scotland.
The Rhynie Chert is exceptional due to its preservation of several different clades of plants, from mosses and lycopods to more unusual, problematic forms. Many fossil animals, including arthropods and arachnids, are also found in the Rhynie Chert, and it offers a unique window on the history of early terrestrial life.
Plant-derived macrofossils become abundant in the Late Devonian and include tree trunks, fronds, and roots. The earliest tree is Archaeopteris, which bears simple, fern-like leaves spirally arranged on branches atop a conifer-like trunk (Meyer-Berthaud et. al., 1999).
Widespread coal swamp deposits across North America and Europe during the Carboniferous Period contain a wealth of fossils containing arborescent lycopods up to 30 meters tall, abundant seed plants, such as conifers and seed ferns, and countless smaller, herbaceous plants.
Angiosperms (flowering plants) evolved during the Mesozoic, and flowering plant pollen and leaves first appear during the Early Cretaceous, approximately 130 million years ago. Palynology is the science that studies contemporary and fossil palynomorphs, including pollen, spores, dinoflagellate cysts, acritarchs, chitinozoans and scolecodonts, together with particulate organic matter (POM) and kerogen found in sedimentary rocks and sediments.
The term palynology was introduced by Hyde and Williams in 1944, following correspondence with the Swedish geologist Antevs, in the pages of the Pollen Analysis Circular (one of the first journals devoted to pollen analysis, and produced by Paul Sears in North America). Hyde and Williams chose palynology on the basis of the Greek words paluno meaning to sprinkle, and pale meaning dust (and thus similar to the Latin word pollen).
Paleoecology
Paleoecology uses data from fossils and subfossils to reconstruct the ecosystems of the past. It includes the study of fossil organisms in terms of their life cycle, their living interactions, their natural environment, their manner of death and burial. Paleoecology's aim is therefore to build the most detailed model possible of the life environment of those living organisms we find today as fossils; such reconstruction work involves complex interactions among environmental factors (temperature, food supplies, degree of solar illumination, etc.). Of course, much of this complex data has been distorted or destroyed by the post-mortem fossilization processes, adding another layer of complexity.
The environmental complexity factor is normally tackled through statistical analysis of the available numerical data (quantitative paleontology or paleostatistics), while post-mortem processes as a source of information are known as the field of taphonomy.
Much paleoecological research focuses on the last two million years (formerly known as the Quarternary period) because older environments are less well-represented in the fossil timeline of evolution. Indeed, many studies concentrate on the Holocene epoch (the last 10,000 years), or the last glacial stage of the Pleistocene epoch (the Wisconsin/Weichsel/Devensian/Würm glaciation of the ice age, from 50,000 to 10,000 years ago). Such studies are useful for understanding the dynamics of ecosystem change and for reconstructing pre-industrialization ecosystems. Many public policy decision-makers have pointed to the importance of using paleoecological studies as a basis for choices made in conservation ecology. Often paleoecologists will use cores from lakes or bogs to reconstruct pollen assemblages, lithology, and to perform geochemical analysis. These tools aid in determining the species composition and climatic conditions, which can contribute to our understanding of how ecosystems change and have changed with climatic and environmental conditions.
Palynology
Palynology is a branch of earth science (geology or geological science) and biological science (biology), particularly plant science (botany). Stratigraphical palynology is a branch of micropalaeontology and paleobotany which studies fossil palynomorphs from the Precambrian to the Holocene.
Methods of study
Palynomorphs are broadly defined as organic-walled microfossils between 5 and 500 micrometres in size. They are extracted from rocks and sediments both physically, by wet sieving, often after ultrasonic treatment, and chemically, by using chemical digestion to remove the non-organic fraction. For example, palynomorphs may be extracted using hydrochloric acid (HCl) to digest carbonate minerals, and hydrofluoric acid (HF) to digest silicate minerals in suitable fume cupboards in specialist laboratories.
Samples are then mounted on microscope slides and examined using light microscopy or scanning electron microscopy. Once the pollen grains have been identified they can be plotted on a pollen diagram which is then used for interpretation. Pollen diagrams are useful in giving evidence of past human activity (anthropogenic impact), vegetation history and climatic history.
Palynology uses many techniques from other related fields such as geology, botany, paleontology, archaeology, pedology, and geography.
Applications
Palynology is used for a diverse range of applications, related to many scientific disciplines:
- Biostratigraphy and geochronology. Geologists use palynological studies in biostratigraphy to correlate strata and determine the relative age of a given bed, horizon, formation or stratigraphical sequence.
- Palaeoecology and climate change. Palynology can be used to reconstruct past vegetation (land plants) and marine and freshwater phytoplankton communities, and so infer past environmental (palaeoenvironmental) and palaeoclimatic conditions.
- Organic palynofacies studies, which examine the preservation of the particulate organic matter and palynomorphs provides information on the depositional environment of sediments and depositional palaeoenvironments of sedimentary rocks.
- Geothermal alteration studies examine the color of palynomorphs extracted from rocks to give the thermal alteration and maturation of sedimentary sequences, which provides estimates of maximum palaeotemperatures.
- Limnology studies. Freshwater palynomorphs and animal and plant fragments, including the prasinophytes and desmids (green algae) can be used to study past lake levels and long term climate change.
- Taxonomy and evolutionary studies.
- Forensic palynology- the study of pollen and other palynomorphs for evidence at a crime scene.
- Allergy studies. Studies of the geographic distribution and seasonal production of pollen, can help sufferers of allergies such as hay fever.
- Melissopalynology - the study of pollen and spores found in honey.
Because the distribution of acritarchs, chitinozoans, dinoflagellate cysts, pollen and spores provides evidence of stratigraphical correlation through biostratigraphy and palaeoenvironmental reconstruction, one common and lucrative application of palynology is in oil and gas exploration.
Palynology also allows scientists to infer the climatic conditions from the vegetation present in an area thousands or millions of years ago. This is a fundamental part of research into [climate change.
Literature]
Notable Paleobotanists
- Kaspar Maria von Sternberg, the "father of paleobotany".
ReferencesISBN links support NWE through referral fees
- Brigitte Meyer-Berthaud, S.E. Scheckler, J. Wendt, "Archaeopteris is the Earliest Modern Tree." Nature, 398, 700-701 (22 April 1999) | doi:10.1038/19516
- Charles H. Wellman, Peter L. Osterloff and Uzma Mohiuddin, "Fragments of the Earliest Land Plants." Nature, 425, 282-285 (18 September 2003) | doi: 10.1038/nature01884
- Kapp, R.O., Davis, O.K., King, J.E. 2000. Guide to Pollen and Spores. (Second edition). American Association of Stratigraphic Palynologists. ISBN 0931871050
- Moore, P.D., et al. 1991. Pollen Analysis (Second Edition). Blackwell Scientific Publications. ISBN 0632021764
- Stewart, W.N. and Rothwell, G.W. 1993. Paleobotany and the evolution of plants, Second edition. Cambridge University Press, Cambridge, UK. ISBN 0-521-38294-7
- Taylor, T. N. and E. L. Taylor. 1993. The Biology and Evolution of Fossil Plants, Prentice-Hall, Inc., Englewood Cliffs, New Jersey, USA. ISBN 0-13-651589-4
- Traverse, A. .1988. Paleopalynology. Unwin Hyman ISBN 0045610010
External links
- International Federation of Palynological Societies
- American Association of Stratigraphic Palynologists, Inc. (AASP)
- Centre for Palynology, University of Sheffield, UK
- Palynology Laboratory, French Institute of Pondicherry, India
- The Palynology Unit, Kew Gardens, UK
- PalDat, palynological database hosted by the University of Vienna, Austria
- The Micropalaeontological Society
- The American Association of Stratigraphic Palynologists (AASP)
- Commission Internationale de Microflore du Paléozoique (CIMP), international commission for Palaeozoic palynology.
- CIMP Subcommission on Acritarchs
- CIMP Chitinozoan Subcommission
- Linnean Society Palynology Specialist Group (LSPSG)
- Canadian Association of Palynologists
- [http://www.geo.arizona.edu/palynology/polident.html Pollen and Spore Identification
- International Organisation of Paleobotany
- Paleobotany Research Group, University Münster, Germany.
- The Biota of Early Terrestrial Ecosystems: The Rhynie Chert, University of Aberdeen, UK.
- The Sternberg Project
- Some historical reconstructions of plants
- Paleobotany - 1911 Encyclopaedia Britannica article
- PaleoNet - listservs and links related to paleontology
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Credits
New World Encyclopedia writers and editors rewrote and completed the Wikipedia article in accordance with New World Encyclopedia standards. This article abides by terms of the Creative Commons CC-by-sa 3.0 License (CC-by-sa), which may be used and disseminated with proper attribution. Credit is due under the terms of this license that can reference both the New World Encyclopedia contributors and the selfless volunteer contributors of the Wikimedia Foundation. To cite this article click here for a list of acceptable citing formats.The history of earlier contributions by wikipedians is accessible to researchers here:
The history of this article since it was imported to New World Encyclopedia:
Note: Some restrictions may apply to use of individual images which are separately licensed.
Credits
New World Encyclopedia writers and editors rewrote and completed the Wikipedia article in accordance with New World Encyclopedia standards. This article abides by terms of the Creative Commons CC-by-sa 3.0 License (CC-by-sa), which may be used and disseminated with proper attribution. Credit is due under the terms of this license that can reference both the New World Encyclopedia contributors and the selfless volunteer contributors of the Wikimedia Foundation. To cite this article click here for a list of acceptable citing formats.The history of earlier contributions by wikipedians is accessible to researchers here:
The history of this article since it was imported to New World Encyclopedia:
Note: Some restrictions may apply to use of individual images which are separately licensed.
