Paleontology

Paleontology, sometimes spelled palaeontology (/ˌpeɪliɒnˈtɒlədʒi, ˌpæli-, -ən-/) is the scientific study of life that existed prior to, and sometimes including, the start of the Holocene Epoch (roughly 11,700 years before present). It includes the study of fossils to determine organisms' evolution and interactions with each other and their environments (their paleoecology). Paleontological observations have been documented as far back as the 5th century BC. The science became established in the 18th century as a result of Georges Cuvier's work on comparative anatomy, and developed rapidly in the 19th century. The term itself originates from Greek παλαιός, palaios, "old, ancient", ὄν, on (gen. ontos), "being, creature" and λόγος, logos, "speech, thought, study".[1]

Paleontology lies on the border between biology and geology, but differs from archaeology in that it excludes the study of anatomically modern humans. It now uses techniques drawn from a wide range of sciences, including biochemistry, mathematics, and engineering. Use of all these techniques has enabled paleontologists to discover much of the evolutionary history of life, almost all the way back to when Earth became capable of supporting life, about 3.8 billion years ago. As knowledge has increased, paleontology has developed specialised sub-divisions, some of which focus on different types of fossil organisms while others study ecology and environmental history, such as ancient climates.

Body fossils and trace fossils are the principal types of evidence about ancient life, and geochemical evidence has helped to decipher the evolution of life before there were organisms large enough to leave body fossils. Estimating the dates of these remains is essential but difficult: sometimes adjacent rock layers allow radiometric dating, which provides absolute dates that are accurate to within 0.5%, but more often paleontologists have to rely on relative dating by solving the "jigsaw puzzles" of biostratigraphy (arrangement of rock layers from youngest to oldest). Classifying ancient organisms is also difficult, as many do not fit well into the Linnaean taxonomy classifying living organisms, and paleontologists more often use cladistics to draw up evolutionary "family trees". The final quarter of the 20th century saw the development of molecular phylogenetics, which investigates how closely organisms are related by measuring the similarity of the DNA in their genomes. Molecular phylogenetics has also been used to estimate the dates when species diverged, but there is controversy about the reliability of the molecular clock on which such estimates depend.

Joda paleontologist
A paleontologist at work at John Day Fossil Beds National Monument

Overview

The simplest definition of "paleontology" is "the study of ancient life".[2] The field seeks information about several aspects of past organisms: "their identity and origin, their environment and evolution, and what they can tell us about the Earth's organic and inorganic past".[3]

A historical science

Europasaurus Praeparation
The preparation of the fossilised bones of Europasaurus holgeri

Paleontology is one of the historical sciences, along with archaeology, geology, astronomy, cosmology, philology and history itself:[4] it aims to describe phenomena of the past and reconstruct their causes.[5] Hence it has three main elements: description of past phenomena; developing a general theory about the causes of various types of change; and applying those theories to specific facts.[4] When trying to explain the past, paleontologists and other historical scientists often construct a set of hypotheses about the causes and then look for a smoking gun, a piece of evidence that strongly accords with one hypothesis over the others. Sometimes the smoking gun is discovered by a fortunate accident during other research. For example, the discovery by Luis and Walter Alvarez of iridium, a mainly extraterrestrial metal, in the CretaceousTertiary boundary layer made asteroid impact the most favored explanation for the Cretaceous–Paleogene extinction event, although the contribution of volcanism continues to be debated.[5]

The other main type of science is experimental science, which is often said to work by conducting experiments to disprove hypotheses about the workings and causes of natural phenomena. This approach cannot prove a hypothesis, since some later experiment may disprove it, but the accumulation of failures to disprove is often compelling evidence in favor. However, when confronted with totally unexpected phenomena, such as the first evidence for invisible radiation, experimental scientists often use the same approach as historical scientists: construct a set of hypotheses about the causes and then look for a "smoking gun".[5]

Related sciences

Paleontology lies between biology and geology since it focuses on the record of past life, but its main source of evidence is fossils in rocks.[6][7] For historical reasons, paleontology is part of the geology department at many universities: in the 19th and early 20th centuries, geology departments found fossil evidence important for dating rocks, while biology departments showed little interest.[8]

Paleontology also has some overlap with archaeology, which primarily works with objects made by humans and with human remains, while paleontologists are interested in the characteristics and evolution of humans as a species. When dealing with evidence about humans, archaeologists and paleontologists may work together – for example paleontologists might identify animal or plant fossils around an archaeological site, to discover what the people who lived there ate; or they might analyze the climate at the time of habitation.[9]

In addition, paleontology often borrows techniques from other sciences, including biology, osteology, ecology, chemistry, physics and mathematics.[2] For example, geochemical signatures from rocks may help to discover when life first arose on Earth,[10] and analyses of carbon isotope ratios may help to identify climate changes and even to explain major transitions such as the Permian–Triassic extinction event.[11] A relatively recent discipline, molecular phylogenetics, compares the DNA and RNA of modern organisms to re-construct the "family trees" of their evolutionary ancestors. It has also been used to estimate the dates of important evolutionary developments, although this approach is controversial because of doubts about the reliability of the "molecular clock".[12] Techniques from engineering have been used to analyse how the bodies of ancient organisms might have worked, for example the running speed and bite strength of Tyrannosaurus,[13][14] or the flight mechanics of Microraptor.[15] It is relatively commonplace to study the internal details of fossils using X-ray microtomography.[16] Paleontology, biology, archaeology, and paleoneurobiology combine to study endocranial casts (endocasts) of species related to humans to clarify the evolution of the human brain.[17]

Paleontology even contributes to astrobiology, the investigation of possible life on other planets, by developing models of how life may have arisen and by providing techniques for detecting evidence of life.[18]

Subdivisions

As knowledge has increased, paleontology has developed specialised subdivisions.[19] Vertebrate paleontology concentrates on fossils from the earliest fish to the immediate ancestors of modern mammals. Invertebrate paleontology deals with fossils such as molluscs, arthropods, annelid worms and echinoderms. Paleobotany studies fossil plants, algae, and fungi. Palynology, the study of pollen and spores produced by land plants and protists, straddles paleontology and botany, as it deals with both living and fossil organisms. Micropaleontology deals with microscopic fossil organisms of all kinds.[20]

Fossil Tyranausaurus Rex at the Royal Tyrell Museum, Alberta, Canada
Analyses using engineering techniques show that Tyrannosaurus had a devastating bite, but raise doubts about its running ability.

Instead of focusing on individual organisms, paleoecology examines the interactions between different ancient organisms, such as their food chains, and the two-way interactions with their environments.[21]  For example, the development of oxygenic photosynthesis by bacteria caused the oxygenation of the atmosphere and hugely increased the productivity and diversity of ecosystems.[22] Together, these led to the evolution of complex eukaryotic cells, from which all multicellular organisms are built.[23]

Paleoclimatology, although sometimes treated as part of paleoecology,[20] focuses more on the history of Earth's climate and the mechanisms that have changed it[24] – which have sometimes included evolutionary developments, for example the rapid expansion of land plants in the Devonian period removed more carbon dioxide from the atmosphere, reducing the greenhouse effect and thus helping to cause an ice age in the Carboniferous period.[25]

Biostratigraphy, the use of fossils to work out the chronological order in which rocks were formed, is useful to both paleontologists and geologists.[26] Biogeography studies the spatial distribution of organisms, and is also linked to geology, which explains how Earth's geography has changed over time.[27]

Sources of evidence

Body fossils

Marrella (fossil)
This Marrella specimen illustrates how clear and detailed the fossils from the Burgess Shale lagerstätte are.

Fossils of organisms' bodies are usually the most informative type of evidence. The most common types are wood, bones, and shells.[28] Fossilisation is a rare event, and most fossils are destroyed by erosion or metamorphism before they can be observed. Hence the fossil record is very incomplete, increasingly so further back in time. Despite this, it is often adequate to illustrate the broader patterns of life's history.[29] There are also biases in the fossil record: different environments are more favorable to the preservation of different types of organism or parts of organisms.[30] Further, only the parts of organisms that were already mineralised are usually preserved, such as the shells of molluscs. Since most animal species are soft-bodied, they decay before they can become fossilised. As a result, although there are 30-plus phyla of living animals, two-thirds have never been found as fossils.[31]

Occasionally, unusual environments may preserve soft tissues. These lagerstätten allow paleontologists to examine the internal anatomy of animals that in other sediments are represented only by shells, spines, claws, etc. – if they are preserved at all. However, even lagerstätten present an incomplete picture of life at the time. The majority of organisms living at the time are probably not represented because lagerstätten are restricted to a narrow range of environments, e.g. where soft-bodied organisms can be preserved very quickly by events such as mudslides; and the exceptional events that cause quick burial make it difficult to study the normal environments of the animals.[32] The sparseness of the fossil record means that organisms are expected to exist long before and after they are found in the fossil record – this is known as the Signor–Lipps effect.[33]

Trace fossils

Trace fossils consist mainly of tracks and burrows, but also include coprolites (fossil feces) and marks left by feeding.[28][34] Trace fossils are particularly significant because they represent a data source that is not limited to animals with easily fossilised hard parts, and they reflect organisms' behaviours. Also many traces date from significantly earlier than the body fossils of animals that are thought to have been capable of making them.[35] Whilst exact assignment of trace fossils to their makers is generally impossible, traces may for example provide the earliest physical evidence of the appearance of moderately complex animals (comparable to earthworms).[34]

Geochemical observations

Geochemical observations may help to deduce the global level of biological activity at a certain period, or the affinity of certain fossils. For example, geochemical features of rocks may reveal when life first arose on Earth,[10] and may provide evidence of the presence of eukaryotic cells, the type from which all multicellular organisms are built.[36] Analyses of carbon isotope ratios may help to explain major transitions such as the Permian–Triassic extinction event.[11]

Classifying ancient organisms

Biological classification L Pengo
Levels in the Linnaean taxonomy.

Naming groups of organisms in a way that is clear and widely agreed is important, as some disputes in paleontology have been based just on misunderstandings over names.[38] Linnaean taxonomy is commonly used for classifying living organisms, but runs into difficulties when dealing with newly discovered organisms that are significantly different from known ones. For example: it is hard to decide at what level to place a new higher-level grouping, e.g. genus or family or order; this is important since the Linnaean rules for naming groups are tied to their levels, and hence if a group is moved to a different level it must be renamed.[39]

Paleontologists generally use approaches based on cladistics, a technique for working out the evolutionary "family tree" of a set of organisms.[38] It works by the logic that, if groups B and C have more similarities to each other than either has to group A, then B and C are more closely related to each other than either is to A. Characters that are compared may be anatomical, such as the presence of a notochord, or molecular, by comparing sequences of DNA or proteins. The result of a successful analysis is a hierarchy of clades – groups that share a common ancestor. Ideally the "family tree" has only two branches leading from each node ("junction"), but sometimes there is too little information to achieve this and paleontologists have to make do with junctions that have several branches. The cladistic technique is sometimes fallible, as some features, such as wings or camera eyes, evolved more than once, convergently – this must be taken into account in analyses.[37]

Evolutionary developmental biology, commonly abbreviated to "Evo Devo", also helps paleontologists to produce "family trees", and understand fossils.[40] For example, the embryological development of some modern brachiopods suggests that brachiopods may be descendants of the halkieriids, which became extinct in the Cambrian period.[41]

Estimating the dates of organisms

Common index fossils used to date rocks in North-East USA.
Pecten gibbus
Calyptraphorusvelatus
Perisphinctestiziani
Trophitessubbullatus
Leptodusamericanus
Cactocrinusmultibrachiatus
Dictyoclostusamericanus
Mucrospinifermucronatus
Cystiphyllumniagarense
Bathyurus extans
Neptunea tabulata
Venericardiaplanicosta
Inoceramuslabiatus
Nerinea trinodosa
Monotissubcircularis
Parafusilinabosei
Lophophyllidiumproliferum
Prolecanites gurleyi
Palmatolepusunicornis
Hexamocaras hertzeri
Tetragraptus fructicosus
Billingsella corrugata
Index fossils blank 01
Common index fossils used to date rocks in North-East USA.
Index fossils blank 01

Paleontology seeks to map out how living things have changed through time. A substantial hurdle to this aim is the difficulty of working out how old fossils are. Beds that preserve fossils typically lack the radioactive elements needed for radiometric dating. This technique is our only means of giving rocks greater than about 50 million years old an absolute age, and can be accurate to within 0.5% or better.[42] Although radiometric dating requires very careful laboratory work, its basic principle is simple: the rates at which various radioactive elements decay are known, and so the ratio of the radioactive element to the element into which it decays shows how long ago the radioactive element was incorporated into the rock. Radioactive elements are common only in rocks with a volcanic origin, and so the only fossil-bearing rocks that can be dated radiometrically are a few volcanic ash layers.[42]

Consequently, paleontologists must usually rely on stratigraphy to date fossils. Stratigraphy is the science of deciphering the "layer-cake" that is the sedimentary record, and has been compared to a jigsaw puzzle.[43] Rocks normally form relatively horizontal layers, with each layer younger than the one underneath it. If a fossil is found between two layers whose ages are known, the fossil's age must lie between the two known ages.[44] Because rock sequences are not continuous, but may be broken up by faults or periods of erosion, it is very difficult to match up rock beds that are not directly next to one another. However, fossils of species that survived for a relatively short time can be used to link up isolated rocks: this technique is called biostratigraphy. For instance, the conodont Eoplacognathus pseudoplanus has a short range in the Middle Ordovician period.[45] If rocks of unknown age are found to have traces of E. pseudoplanus, they must have a mid-Ordovician age. Such index fossils must be distinctive, be globally distributed and have a short time range to be useful. However, misleading results are produced if the index fossils turn out to have longer fossil ranges than first thought.[46] Stratigraphy and biostratigraphy can in general provide only relative dating (A was before B), which is often sufficient for studying evolution. However, this is difficult for some time periods, because of the problems involved in matching up rocks of the same age across different continents.[47]

Family-tree relationships may also help to narrow down the date when lineages first appeared. For instance, if fossils of B or C date to X million years ago and the calculated "family tree" says A was an ancestor of B and C, then A must have evolved more than X million years ago.

It is also possible to estimate how long ago two living clades diverged – i.e. approximately how long ago their last common ancestor must have lived – by assuming that DNA mutations accumulate at a constant rate. These "molecular clocks", however, are fallible, and provide only a very approximate timing: for example, they are not sufficiently precise and reliable for estimating when the groups that feature in the Cambrian explosion first evolved,[48] and estimates produced by different techniques may vary by a factor of two.[12]

History of life

Runzelmarken
This wrinkled "elephant skin" texture is a trace fossil of a non-stromatolite microbial mat. The image shows the location, in the Burgsvik beds of Sweden, where the texture was first identified as evidence of a microbial mat.[49]

Earth formed about 4,570 million years ago and, after a collision that formed the Moon about 40 million years later, may have cooled quickly enough to have oceans and an atmosphere about 4,440 million years ago.[50] There is evidence on the Moon of a Late Heavy Bombardment by asteroids from 4,000 to 3,800 million years ago. If, as seems likely, such a bombardment struck Earth at the same time, the first atmosphere and oceans may have been stripped away.[51]

Paleontology traces the evolutionary history of life back to over 3,000 million years ago, possibly as far as 3,800 million years ago.[52] The oldest clear evidence of life on Earth dates to 3,000 million years ago, although there have been reports, often disputed, of fossil bacteria from 3,400 million years ago and of geochemical evidence for the presence of life 3,800 million years ago.[10][53] Some scientists have proposed that life on Earth was "seeded" from elsewhere,[54] but most research concentrates on various explanations of how life could have arisen independently on Earth.[55]

For about 2,000 million years microbial mats, multi-layered colonies of different bacteria, were the dominant life on Earth.[56] The evolution of oxygenic photosynthesis enabled them to play the major role in the oxygenation of the atmosphere[57] from about 2,400 million years ago. This change in the atmosphere increased their effectiveness as nurseries of evolution.[58] While eukaryotes, cells with complex internal structures, may have been present earlier, their evolution speeded up when they acquired the ability to transform oxygen from a poison to a powerful source of metabolic energy. This innovation may have come from primitive eukaryotes capturing oxygen-powered bacteria as endosymbionts and transforming them into organelles called mitochondria.[52][59] The earliest evidence of complex eukaryotes with organelles (such as mitochondria) dates from 1,850 million years ago.[23]

Opabinia BW2
Opabinia sparked modern interest in the Cambrian explosion.

Multicellular life is composed only of eukaryotic cells, and the earliest evidence for it is the Francevillian Group Fossils from 2,100 million years ago,[60] although specialisation of cells for different functions first appears between 1,430 million years ago (a possible fungus) and 1,200 million years ago (a probable red alga). Sexual reproduction may be a prerequisite for specialisation of cells, as an asexual multicellular organism might be at risk of being taken over by rogue cells that retain the ability to reproduce.[61][62]

The earliest known animals are cnidarians from about 580 million years ago, but these are so modern-looking that must be descendants of earlier animals.[63] Early fossils of animals are rare because they had not developed mineralised, easily fossilized hard parts until about 548 million years ago.[64] The earliest modern-looking bilaterian animals appear in the Early Cambrian, along with several "weird wonders" that bear little obvious resemblance to any modern animals. There is a long-running debate about whether this Cambrian explosion was truly a very rapid period of evolutionary experimentation; alternative views are that modern-looking animals began evolving earlier but fossils of their precursors have not yet been found, or that the "weird wonders" are evolutionary "aunts" and "cousins" of modern groups.[65] Vertebrates remained a minor group until the first jawed fish appeared in the Late Ordovician.[66][67]

Yanoconodon BW
At about 13 centimetres (5.1 in) the Early Cretaceous Yanoconodon was longer than the average mammal of the time.[68]

The spread of life from water to land required organisms to solve several problems, including protection against drying out and supporting themselves against gravity.[69][70][71][72] The earliest evidence of land plants and land invertebrates date back to about 476 million years ago and 490 million years ago respectively.[71][73] The lineage that produced land vertebrates evolved later but very rapidly between 370 million years ago and 360 million years ago;[74] recent discoveries have overturned earlier ideas about the history and driving forces behind their evolution.[75] Land plants were so successful that their detritus caused an ecological crisis in the Late Devonian, until the evolution of fungi that could digest dead wood.[25]

House sparrow04
Birds are the only surviving dinosaurs.[76]

During the Permian period, synapsids, including the ancestors of mammals, may have dominated land environments,[77] but this ended with the Permian–Triassic extinction event 251 million years ago, which came very close to wiping out all complex life.[78] The extinctions were apparently fairly sudden, at least among vertebrates.[79] During the slow recovery from this catastrophe a previously obscure group, archosaurs, became the most abundant and diverse terrestrial vertebrates. One archosaur group, the dinosaurs, were the dominant land vertebrates for the rest of the Mesozoic,[80] and birds evolved from one group of dinosaurs.[76] During this time mammals' ancestors survived only as small, mainly nocturnal insectivores, which may have accelerated the development of mammalian traits such as endothermy and hair.[81] After the Cretaceous–Paleogene extinction event 66 million years ago[82] killed off all the dinosaurs except the birds, mammals increased rapidly in size and diversity, and some took to the air and the sea.[83][84][85]

Fossil evidence indicates that flowering plants appeared and rapidly diversified in the Early Cretaceous between 130 million years ago and 90 million years ago.[86] Their rapid rise to dominance of terrestrial ecosystems is thought to have been propelled by coevolution with pollinating insects.[87] Social insects appeared around the same time and, although they account for only small parts of the insect "family tree", now form over 50% of the total mass of all insects.[88]

Humans evolved from a lineage of upright-walking apes whose earliest fossils date from over 6 million years ago.[89] Although early members of this lineage had chimp-sized brains, about 25% as big as modern humans', there are signs of a steady increase in brain size after about 3 million years ago.[90] There is a long-running debate about whether modern humans are descendants of a single small population in Africa, which then migrated all over the world less than 200,000 years ago and replaced previous hominine species, or arose worldwide at the same time as a result of interbreeding.[91]

Mass extinctions

CambrianOrdovicianSilurianDevonianCarboniferousPermianTriassicJurassicCretaceousPaleogeneNeogene
Marine extinction intensity during the Phanerozoic
%
Millions of years ago
CambrianOrdovicianSilurianDevonianCarboniferousPermianTriassicJurassicCretaceousPaleogeneNeogene
Apparent extinction intensity, i.e. the fraction of genera going extinct at any given time, as reconstructed from the fossil record (graph not meant to include recent epoch of Holocene extinction event)

Life on earth has suffered occasional mass extinctions at least since 542 million years ago. Despite their disastrous effects, mass extinctions have sometimes accelerated the evolution of life on earth. When dominance of an ecological niche passes from one group of organisms to another, this is rarely because the new dominant group outcompetes the old, but usually because an extinction event allows new group to outlive the old and move into its niche.[92][93]

The fossil record appears to show that the rate of extinction is slowing down, with both the gaps between mass extinctions becoming longer and the average and background rates of extinction decreasing. However, it is not certain whether the actual rate of extinction has altered, since both of these observations could be explained in several ways:[94]

  • The oceans may have become more hospitable to life over the last 500 million years and less vulnerable to mass extinctions: dissolved oxygen became more widespread and penetrated to greater depths; the development of life on land reduced the run-off of nutrients and hence the risk of eutrophication and anoxic events; marine ecosystems became more diversified so that food chains were less likely to be disrupted.[95][96]
  • Reasonably complete fossils are very rare: most extinct organisms are represented only by partial fossils, and complete fossils are rarest in the oldest rocks. So paleontologists have mistakenly assigned parts of the same organism to different genera, which were often defined solely to accommodate these finds – the story of Anomalocaris is an example of this.[97] The risk of this mistake is higher for older fossils because these are often unlike parts of any living organism. Many "superfluous" genera are represented by fragments that are not found again, and these "superfluous" genera are interpreted as becoming extinct very quickly.[94]
Phanerozoic biodiversity as shown by the fossil record
All genera
"Well-defined" genera
Trend line
"Big Five" mass extinctions
Other mass extinctions
Million years ago
Thousands of genera
Phanerozoic biodiversity blank 01
Phanerozoic biodiversity as shown by the fossil record
Phanerozoic biodiversity blank 01

Biodiversity in the fossil record, which is

"the number of distinct genera alive at any given time; that is, those whose first occurrence predates and whose last occurrence postdates that time"[98]

shows a different trend: a fairly swift rise from 542 to 400 million years ago, a slight decline from 400 to 200 million years ago, in which the devastating Permian–Triassic extinction event is an important factor, and a swift rise from 200 million years ago to the present.[98]

History

Cuvier elephant jaw
This illustration of an Indian elephant jaw and a mammoth jaw (top) is from Cuvier's 1796 paper on living and fossil elephants.

Although paleontology became established around 1800, earlier thinkers had noticed aspects of the fossil record. The ancient Greek philosopher Xenophanes (570–480 BC) concluded from fossil sea shells that some areas of land were once under water.[99] During the Middle Ages the Persian naturalist Ibn Sina, known as Avicenna in Europe, discussed fossils and proposed a theory of petrifying fluids on which Albert of Saxony elaborated in the 14th century.[100] The Chinese naturalist Shen Kuo (1031–1095) proposed a theory of climate change based on the presence of petrified bamboo in regions that in his time were too dry for bamboo.[101]

In early modern Europe, the systematic study of fossils emerged as an integral part of the changes in natural philosophy that occurred during the Age of Reason. In the Italian Renaissance, Leonardo Da Vinci made various significant contributions to the field as well depicted numerous fossils. Leonardo's contributions are central to the history of paleontology because he established a line of continuity between the two main branches of paleontology—ichnology and body fossil paleontology.[102][103][104] He identified the following:[102]

  1. The biogenic nature of ichnofossils, i.e. ichnofossils were structures left by living organisms;
  2. The utility of ichnofossils as paleoenvironmental tools—certain ichnofossils show the marine origin of rock strata;
  3. The importance of the neoichnological approach—recent traces are a key to understanding ichnofossils;
  4. The independence and complementary evidence of ichnofossils and body fossils—ichnofossils are distinct from body fossils, but can be integrated with body fossils to provide paleontological information

At the end of the 18th century Georges Cuvier's work established comparative anatomy as a scientific discipline and, by proving that some fossil animals resembled no living ones, demonstrated that animals could become extinct, leading to the emergence of paleontology.[105] The expanding knowledge of the fossil record also played an increasing role in the development of geology, particularly stratigraphy.[106]

The first half of the 19th century saw geological and paleontological activity become increasingly well organised with the growth of geologic societies and museums[107][108] and an increasing number of professional geologists and fossil specialists. Interest increased for reasons that were not purely scientific, as geology and paleontology helped industrialists to find and exploit natural resources such as coal.[109]

This contributed to a rapid increase in knowledge about the history of life on Earth and to progress in the definition of the geologic time scale, largely based on fossil evidence. In 1822 Henri Marie Ducrotay de Blanville, editor of Journal de Physique, coined the word "palaeontology" to refer to the study of ancient living organisms through fossils.[110] As knowledge of life's history continued to improve, it became increasingly obvious that there had been some kind of successive order to the development of life. This encouraged early evolutionary theories on the transmutation of species.[111] After Charles Darwin published Origin of Species in 1859, much of the focus of paleontology shifted to understanding evolutionary paths, including human evolution, and evolutionary theory.[111]

Haikouichthys4
Haikouichthys, from about 518 million years ago in China, may be the earliest known fish.[112]

The last half of the 19th century saw a tremendous expansion in paleontological activity, especially in North America.[113] The trend continued in the 20th century with additional regions of the Earth being opened to systematic fossil collection. Fossils found in China near the end of the 20th century have been particularly important as they have provided new information about the earliest evolution of animals, early fish, dinosaurs and the evolution of birds.[114] The last few decades of the 20th century saw a renewed interest in mass extinctions and their role in the evolution of life on Earth.[115] There was also a renewed interest in the Cambrian explosion that apparently saw the development of the body plans of most animal phyla. The discovery of fossils of the Ediacaran biota and developments in paleobiology extended knowledge about the history of life back far before the Cambrian.[65]

Increasing awareness of Gregor Mendel's pioneering work in genetics led first to the development of population genetics and then in the mid-20th century to the modern evolutionary synthesis, which explains evolution as the outcome of events such as mutations and horizontal gene transfer, which provide genetic variation, with genetic drift and natural selection driving changes in this variation over time.[116] Within the next few years the role and operation of DNA in genetic inheritance were discovered, leading to what is now known as the "Central Dogma" of molecular biology.[117] In the 1960s molecular phylogenetics, the investigation of evolutionary "family trees" by techniques derived from biochemistry, began to make an impact, particularly when it was proposed that the human lineage had diverged from apes much more recently than was generally thought at the time.[118] Although this early study compared proteins from apes and humans, most molecular phylogenetics research is now based on comparisons of RNA and DNA.[119]

See also

References

  1. ^ "paleontology". Online Etymology Dictionary. Archived from the original on 2013-03-07.
  2. ^ a b Cowen, R. (2000). History of Life (3rd ed.). Blackwell Science. p. xi. ISBN 0-632-04444-6.
  3. ^ Laporte, L.F. (October 1988). "What, after All, Is Paleontology?". PALAIOS. 3 (5): 453. Bibcode:1988Palai...3..453L. doi:10.2307/3514718. JSTOR 3514718.
  4. ^ a b Laudan, R. (1992). "What's so Special about the Past?". In Nitecki, M.H.; Nitecki, D.V. (eds.). History and Evolution. SUNY Press. p. 58. ISBN 0-7914-1211-3.
  5. ^ a b c Cleland, C.E. (September 2002). "Methodological and Epistemic Differences between Historical Science and Experimental Science". Philosophy of Science. 69 (3): 474–496. doi:10.1086/342453. Archived from the original on October 3, 2008. Retrieved September 17, 2008.
  6. ^ "paleontology | science". Encyclopædia Britannica. Archived from the original on 2017-08-24. Retrieved 2017-08-24.
  7. ^ McGraw-Hill Encyclopedia of Science & Technology. McGraw-Hill. 2002. p. 58. ISBN 0-07-913665-6.
  8. ^ Laudan, R. (1992). "What's so Special about the Past?". In Nitecki, M.H.; Nitecki, D.V. (eds.). History and Evolution. SUNY Press. p. 57. ISBN 0-7914-1211-3.
  9. ^ "How does paleontology differ from anthropology and archaeology?". University of California Museum of Paleontology. Archived from the original on September 16, 2008. Retrieved September 17, 2008.
  10. ^ a b c Brasier, M.; McLoughlin, N.; Green, O. & Wacey, D. (June 2006). "A fresh look at the fossil evidence for early Archaean cellular life" (PDF). Philosophical Transactions of the Royal Society B. 361 (1470): 887–902. doi:10.1098/rstb.2006.1835. PMC 1578727. PMID 16754605. Archived (PDF) from the original on September 11, 2008. Retrieved August 30, 2008.
  11. ^ a b Twitchett RJ; Looy CV; Morante R; Visscher H; Wignall PB (2001). "Rapid and synchronous collapse of marine and terrestrial ecosystems during the end-Permian biotic crisis". Geology. 29 (4): 351–354. Bibcode:2001Geo....29..351T. doi:10.1130/0091-7613(2001)029<0351:RASCOM>2.0.CO;2.
  12. ^ a b Peterson, Kevin J. & Butterfield, N.J. (2005). "Origin of the Eumetazoa: Testing ecological predictions of molecular clocks against the Proterozoic fossil record". Proceedings of the National Academy of Sciences. 102 (27): 9547–52. Bibcode:2005PNAS..102.9547P. doi:10.1073/pnas.0503660102. PMC 1172262. PMID 15983372.
  13. ^ Hutchinson, J. R. & Garcia, M. (28 February 2002). "Tyrannosaurus was not a fast runner". Nature. 415 (6875): 1018–1021. Bibcode:2002Natur.415.1018H. doi:10.1038/4151018a. PMID 11875567. Summary in press release No Olympian: Analysis hints T. rex ran slowly, if at all Archived 2008-04-15 at the Wayback Machine
  14. ^ Meers, M.B. (August 2003). "Maximum bite force and prey size of Tyrannosaurus rex and their relationships to the inference of feeding behavior". Historical Biology. 16 (1): 1–12. doi:10.1080/0891296021000050755. Archived from the original on 2008-07-05.
  15. ^ "The Four Winged Dinosaur: Wind Tunnel Test". NOVA. Retrieved June 5, 2010.
  16. ^ Garwood, Russell J.; Rahman, Imran A.; Sutton, Mark D. A. (2010). "From clergymen to computers: the advent of virtual palaeontology". Geology Today. 26 (3): 96–100. doi:10.1111/j.1365-2451.2010.00753.x. Retrieved June 16, 2015.
  17. ^ Bruner, Emiliano (November 2004). "Geometric morphometrics and palaeoneurology: brain shape evolution in the genus Homo". Journal of Human Evolution. 47 (5): 279–303. doi:10.1016/j.jhevol.2004.03.009. PMID 15530349.
  18. ^ Cady, S.L. (April 1998). "Astrobiology: A New Frontier for 21st Century Paleontologists". PALAIOS. 13 (2): 95–97. Bibcode:1998Palai..13...95C. doi:10.2307/3515482. JSTOR 3515482. PMID 11542813.
  19. ^ Plotnick, R.E. "A Somewhat Fuzzy Snapshot of Employment in Paleontology in the United States". Palaeontologia Electronica. Coquina Press. 11 (1). ISSN 1094-8074. Archived from the original on May 18, 2008. Retrieved September 17, 2008.
  20. ^ a b "What is Paleontology?". University of California Museum of Paleontology. Archived from the original on August 3, 2008. Retrieved September 17, 2008.
  21. ^ Kitchell, J.A. (1985). "Evolutionary Paleocology: Recent Contributions to Evolutionary Theory". Paleobiology. 11 (1): 91–104. doi:10.1017/S0094837300011428. Archived from the original on August 3, 2008. Retrieved September 17, 2008.
  22. ^ Hoehler, T.M.; Bebout, B.M. & Des Marais, D.J. (19 July 2001). "The role of microbial mats in the production of reduced gases on the early Earth". Nature. 412 (6844): 324–327. doi:10.1038/35085554. PMID 11460161.
  23. ^ a b Hedges, S.B.; Blair, J.E; Venturi, M.L. & Shoe, J.L. (January 2004). "A molecular timescale of eukaryote evolution and the rise of complex multicellular life". BMC Evolutionary Biology. 4: 2. doi:10.1186/1471-2148-4-2. PMC 341452. PMID 15005799.
  24. ^ "Paleoclimatology". Ohio State University. Archived from the original on November 9, 2007. Retrieved September 17, 2008.
  25. ^ a b Algeo, T.J. & Scheckler, S.E. (1998). "Terrestrial-marine teleconnections in the Devonian: links between the evolution of land plants, weathering processes, and marine anoxic events". Philosophical Transactions of the Royal Society B. 353 (1365): 113–130. doi:10.1098/rstb.1998.0195. PMC 1692181.
  26. ^ "Biostratigraphy: William Smith". Archived from the original on July 24, 2008. Retrieved September 17, 2008.
  27. ^ "Biogeography: Wallace and Wegener (1 of 2)". University of California Museum of Paleontology and University of California at Berkeley. Archived from the original on May 15, 2008. Retrieved September 17, 2008.
  28. ^ a b "What is paleontology?". University of California Museum of Paleontology. Archived from the original on September 16, 2008. Retrieved September 17, 2008.
  29. ^ Benton MJ; Wills MA; Hitchin R (2000). "Quality of the fossil record through time". Nature. 403 (6769): 534–7. Bibcode:2000Natur.403..534B. doi:10.1038/35000558. PMID 10676959.
    Non-technical summary Archived 2007-08-09 at the Wayback Machine
  30. ^ Butterfield, N.J. (2003). "Exceptional Fossil Preservation and the Cambrian Explosion". Integrative and Comparative Biology. 43 (1): 166–177. doi:10.1093/icb/43.1.166. PMID 21680421. Archived from the original on September 5, 2008. Retrieved June 28, 2008.
  31. ^ Cowen, R. (2000). History of Life (3rd ed.). Blackwell Science. p. 61. ISBN 0-632-04444-6.
  32. ^ Butterfield, N.J. (2001). "Ecology and evolution of Cambrian plankton". The Ecology of the Cambrian Radiation. New York: Columbia University Press: 200–216. Retrieved September 27, 2007.
  33. ^ Signor, P.W. (1982). "Sampling bias, gradual extinction patterns and catastrophes in the fossil record". Geological Implications of Impacts of Large Asteroids and Comets on the Earth. Boulder, CO: Geological Society of America: 291–296. A 84–25651 10–42. Retrieved January 1, 2008.
  34. ^ a b Fedonkin, M.A.; Gehling, J.G.; Grey, K.; Narbonne, G.M.; Vickers-Rich, P. (2007). The Rise of Animals: Evolution and Diversification of the Kingdom Animalia. JHU Press. pp. 213–216. ISBN 978-0-8018-8679-9.
  35. ^ e.g. Seilacher, A. (1994). "How valid is Cruziana Stratigraphy?". International Journal of Earth Sciences. 83 (4): 752–758. Bibcode:1994GeoRu..83..752S. doi:10.1007/BF00251073.
  36. ^ Brocks, J.J.; Logan, G.A.; Buick, R. & Summons, R.E. (1999). "Archaean molecular fossils and the rise of eukaryotes". Science. 285 (5430): 1033–1036. doi:10.1126/science.285.5430.1033. PMID 10446042.
  37. ^ a b Cowen, R. (2000). History of Life (3rd ed.). Blackwell Science. pp. 47–50. ISBN 0-632-04444-6.
  38. ^ a b Brochu, C.A & Sumrall, C.D. (July 2001). "Phylogenetic Nomenclature and Paleontology". Journal of Paleontology. 75 (4): 754–757. doi:10.1666/0022-3360(2001)075<0754:PNAP>2.0.CO;2. ISSN 0022-3360. JSTOR 1306999.
  39. ^ Ereshefsky, M. (2001). The Poverty of the Linnaean Hierarchy: A Philosophical Study of Biological Taxonomy. Cambridge University Press. p. 5. ISBN 0-521-78170-1.
  40. ^ Garwood, Russell J.; Sharma, Prashant P.; Dunlop, Jason A.; Giribet, Gonzalo (2014). "A Paleozoic Stem Group to Mite Harvestmen Revealed through Integration of Phylogenetics and Development". Current Biology. 24 (9): 1017–1023. doi:10.1016/j.cub.2014.03.039. PMID 24726154. Retrieved April 17, 2014.
  41. ^ Cohen, B. L.; Holmer, L. E. & Luter, C. (2003). "The brachiopod fold: a neglected body plan hypothesis" (PDF). Palaeontology. 46 (1): 59–65. doi:10.1111/1475-4983.00287. Archived (PDF) from the original on October 3, 2008. Retrieved August 7, 2008.
  42. ^ a b Martin, M.W.; Grazhdankin, D.V.; Bowring, S.A.; Evans, D.A.D.; Fedonkin, M.A.; Kirschvink, J.L. (May 5, 2000). "Age of Neoproterozoic Bilaterian Body and Trace Fossils, White Sea, Russia: Implications for Metazoan Evolution". Science (abstract). 288 (5467): 841–5. Bibcode:2000Sci...288..841M. doi:10.1126/science.288.5467.841. PMID 10797002.
  43. ^ Pufahl, P.K.; Grimm, K.A.; Abed, A.M. & Sadaqah, R.M.Y. (October 2003). "Upper Cretaceous (Campanian) phosphorites in Jordan: implications for the formation of a south Tethyan phosphorite giant". Sedimentary Geology. 161 (3–4): 175–205. Bibcode:2003SedG..161..175P. doi:10.1016/S0037-0738(03)00070-8.
  44. ^ "Geologic Time: Radiometric Time Scale". U.S. Geological Survey. Archived from the original on September 21, 2008. Retrieved September 20, 2008.
  45. ^ Löfgren, A. (2004). "The conodont fauna in the Middle Ordovician Eoplacognathus pseudoplanus Zone of Baltoscandia". Geological Magazine. 141 (4): 505–524. Bibcode:2004GeoM..141..505L. doi:10.1017/S0016756804009227.
  46. ^ Gehling, James; Jensen, Sören; Droser, Mary; Myrow, Paul; Narbonne, Guy (March 2001). "Burrowing below the basal Cambrian GSSP, Fortune Head, Newfoundland". Geological Magazine. 138 (2): 213–218. Bibcode:2001GeoM..138..213G. doi:10.1017/S001675680100509X.
  47. ^ e.g. Gehling, James; Jensen, Sören; Droser, Mary; Myrow, Paul; Narbonne, Guy (March 2001). "Burrowing below the basal Cambrian GSSP, Fortune Head, Newfoundland". Geological Magazine. 138 (2): 213–218. Bibcode:2001GeoM..138..213G. doi:10.1017/S001675680100509X.
  48. ^ Hug, L.A. & Roger, A.J. (2007). "The Impact of Fossils and Taxon Sampling on Ancient Molecular Dating Analyses". Molecular Biology and Evolution. 24 (8): 889–1897. doi:10.1093/molbev/msm115. PMID 17556757.
  49. ^ Manten, A.A. (1966). "Some problematic shallow-marine structures". Marine Geol. 4 (3): 227–232. Bibcode:1966MGeol...4..227M. doi:10.1016/0025-3227(66)90023-5. Archived from the original on October 21, 2008. Retrieved June 18, 2007.
  50. ^ * "Early Earth Likely Had Continents And Was Habitable". 2005-11-17. Archived from the original on 2008-10-14.
    * Cavosie, A. J.; J. W. Valley, S. A., Wilde & E.I.M.F. (July 15, 2005). "Magmatic δ18O in 4400–3900 Ma detrital zircons: A record of the alteration and recycling of crust in the Early Archean". Earth and Planetary Science Letters. 235 (3–4): 663–681. Bibcode:2005E&PSL.235..663C. doi:10.1016/j.epsl.2005.04.028.CS1 maint: Multiple names: authors list (link)
  51. ^ Dauphas, N.; Robert, F. & Marty, B. (December 2000). "The Late Asteroidal and Cometary Bombardment of Earth as Recorded in Water Deuterium to Protium Ratio". Icarus. 148 (2): 508–512. Bibcode:2000Icar..148..508D. doi:10.1006/icar.2000.6489.
  52. ^ a b Garwood, Russell J. (2012). "Patterns In Palaeontology: The first 3 billion years of evolution". Palaeontology Online. 2 (11): 1–14. Archived from the original on June 26, 2015. Retrieved June 25, 2015.
  53. ^ Schopf, J. (2006). "Fossil evidence of Archaean life". Philos Trans R Soc Lond B Biol Sci. 361 (1470): 869–85. doi:10.1098/rstb.2006.1834. PMC 1578735. PMID 16754604.
  54. ^ *Arrhenius, S. (1903). "The Propagation of Life in Space". Die Umschau. 7: 32. Bibcode:1980qel..book...32A. Reprinted in Goldsmith, D. (ed.). The Quest for Extraterrestrial Life. University Science Books. ISBN 0-19-855704-3.
    * Hoyle, F. & Wickramasinghe, C. (1979). "On the Nature of Interstellar Grains". Astrophysics and Space Science. 66: 77–90. Bibcode:1979Ap&SS..66...77H. doi:10.1007/BF00648361.
    * Crick, F. H.; Orgel, L. E. (1973). "Directed Panspermia". Icarus. 19 (3): 341–348. Bibcode:1973Icar...19..341C. doi:10.1016/0019-1035(73)90110-3.
  55. ^ Peretó, J. (2005). "Controversies on the origin of life" (PDF). Int. Microbiol. 8 (1): 23–31. PMID 15906258. Archived from the original (PDF) on August 24, 2015. Retrieved October 7, 2007.
  56. ^ Krumbein, W.E.; Brehm, U.; Gerdes, G.; Gorbushina, A.A.; Levit, G. & Palinska, K.A. (2003). "Biofilm, Biodictyon, Biomat Microbialites, Oolites, Stromatolites, Geophysiology, Global Mechanism, Parahistology". In Krumbein, W.E.; Paterson, D.M. & Zavarzin, G.A. (eds.). Fossil and Recent Biofilms: A Natural History of Life on Earth (PDF). Kluwer Academic. pp. 1–28. ISBN 1-4020-1597-6. Archived from the original (PDF) on January 6, 2007. Retrieved July 9, 2008.
  57. ^ Hoehler, T.M.; Bebout, B.M. & Des Marais, D.J. (July 19, 2001). "The role of microbial mats in the production of reduced gases on the early Earth". Nature. 412 (6844): 324–327. doi:10.1038/35085554. PMID 11460161.
  58. ^ Nisbet, E.G. & Fowler, C.M.R. (December 7, 1999). "Archaean metabolic evolution of microbial mats". Proceedings of the Royal Society B. 266 (1436): 2375. doi:10.1098/rspb.1999.0934. PMC 1690475.
  59. ^ Gray MW; Burger G; Lang BF (March 1999). "Mitochondrial evolution". Science. 283 (5407): 1476–81. Bibcode:1999Sci...283.1476G. doi:10.1126/science.283.5407.1476. PMC 3428767. PMID 10066161.
  60. ^ El Albani, Abderrazak; Bengtson, Stefan; Canfield, Donald E.; Bekker, Andrey; Macchiarelli, Reberto; Mazurier, Arnaud; Hammarlund, Emma U.; Boulvais, Philippe; et al. (July 2010). "Large colonial organisms with coordinated growth in oxygenated environments 2.1 Gyr ago". Nature. 466 (7302): 100–104. Bibcode:2010Natur.466..100A. doi:10.1038/nature09166. PMID 20596019.
  61. ^ Butterfield, N.J. (September 2000). "Bangiomorpha pubescens n. gen., n. sp.: implications for the evolution of sex, multicellularity, and the Mesoproterozoic/Neoproterozoic radiation of eukaryotes". Paleobiology. 26 (3): 386–404. doi:10.1666/0094-8373(2000)026<0386:BPNGNS>2.0.CO;2. ISSN 0094-8373. Archived from the original on 2007-03-07. Retrieved 2008-09-02.
  62. ^ Butterfield, N.J. (2005). "Probable Proterozoic fungi". Paleobiology. 31 (1): 165–182. doi:10.1666/0094-8373(2005)031<0165:PPF>2.0.CO;2. ISSN 0094-8373. Archived from the original on 2009-01-29. Retrieved 2008-09-02.
  63. ^ Chen, J.-Y.; Oliveri, P.; Gao, F.; Dornbos, S.Q.; Li, C-W.; Bottjer, D.J. & Davidson, E.H. (August 2002). "Precambrian Animal Life: Probable Developmental and Adult Cnidarian Forms from Southwest China" (PDF). Developmental Biology. 248 (1): 182–196. doi:10.1006/dbio.2002.0714. PMID 12142030. Archived from the original (PDF) on September 11, 2008. Retrieved September 3, 2008.
  64. ^ Bengtson, S. (2004). Lipps, J.H.; Waggoner, B.M. (eds.). "Neoproterozoic — Cambrian Biological Revolutions" (PDF). Paleontological Society Papers. 10: 67–78. doi:10.1017/S1089332600002345. Archived from the original (PDF) on 2017-02-11. Retrieved July 18, 2008.
  65. ^ a b Marshall, C.R. (2006). "Explaining the Cambrian "Explosion" of Animals". Annu. Rev. Earth Planet. Sci. 34: 355–384. Bibcode:2006AREPS..34..355M. doi:10.1146/annurev.earth.33.031504.103001.
  66. ^ Conway Morris, S. (August 2, 2003). "Once we were worms". New Scientist. 179 (2406): 34. Archived from the original on July 25, 2008. Retrieved September 5, 2008.
  67. ^ Sansom I.J., Smith, M.M. & Smith, M.P. (2001). "The Ordovician radiation of vertebrates". In Ahlberg, P.E. (ed.). Major Events in Early Vertebrate Evolution. Taylor and Francis. pp. 156–171. ISBN 0-415-23370-4.CS1 maint: Multiple names: authors list (link)
  68. ^ Luo, Z.; Chen, P.; Li, G. & Chen, M. (March 2007). "A new eutriconodont mammal and evolutionary development in early mammals". Nature. 446 (7133): 288–293. Bibcode:2007Natur.446..288L. doi:10.1038/nature05627. PMID 17361176.
  69. ^ Russell Garwood & Gregory Edgecombe (2011). "Early terrestrial animals, evolution and uncertainty". Evolution: Education and Outreach. 4 (3): 489–501. doi:10.1007/s12052-011-0357-y.
  70. ^ Selden, P.A. (2001). "Terrestrialization of Animals". In Briggs, D.E.G.; Crowther, P.R. (eds.). Palaeobiology II: A Synthesis. Blackwell. pp. 71–74. ISBN 0-632-05149-3.
  71. ^ a b Kenrick, P. & Crane, P.R. (September 1997). "The origin and early evolution of plants on land" (PDF). Nature. 389 (6646): 33. Bibcode:1997Natur.389...33K. doi:10.1038/37918. Archived (PDF) from the original on 2010-12-17.
  72. ^ Laurin, M. (2010). How Vertebrates Left the Water. Berkeley, California, USA.: University of California Press. ISBN 978-0-520-26647-6.
  73. ^ MacNaughton, R.B.; Cole, J.M.; Dalrymple, R.W.; Braddy, S.J.; Briggs, D.E.G. & Lukie, T.D. (May 2002). "First steps on land: Arthropod trackways in Cambrian-Ordovician eolian sandstone, southeastern Ontario, Canada". Geology. 30 (5): 391–394. Bibcode:2002Geo....30..391M. doi:10.1130/0091-7613(2002)030<0391:FSOLAT>2.0.CO;2. ISSN 0091-7613. Archived from the original on 2006-02-13.
  74. ^ Gordon, M.S; Graham, J.B. & Wang, T. (September–October 2004). "Revisiting the Vertebrate Invasion of the Land". Physiological and Biochemical Zoology. 77 (5): 697–699. doi:10.1086/425182.
  75. ^ Clack, J.A. (November 2005). "Getting a Leg Up on Land". Scientific American. Retrieved September 6, 2008.
  76. ^ a b Padian, Kevin. (2004). "Basal Avialae". In Weishampel, David B.; Dodson, Peter; Osmólska, Halszka (eds.). The Dinosauria (Second ed.). Berkeley: University of California Press. pp. 210–231. ISBN 0-520-24209-2.
  77. ^ Sidor, C.A.; O'Keefe, F.R.; Damiani, R.; Steyer, J.S.; Smith, R.M.H.; Larsson, H.C.E.; Sereno, P.C.; Ide, O & Maga, A. (April 2005). "Permian tetrapods from the Sahara show climate-controlled endemism in Pangaea". Nature. 434 (7035): 886–889. Bibcode:2005Natur.434..886S. doi:10.1038/nature03393. PMID 15829962.
  78. ^ Benton M.J. (2005). When Life Nearly Died: The Greatest Mass Extinction of All Time. Thames & Hudson. ISBN 978-0-500-28573-2.
  79. ^ Ward, P.D.; Botha, J.; Buick, R.; Kock, M.O.; et al. (2005). "Abrupt and gradual extinction among late Permian land vertebrates in the Karoo Basin, South Africa" (PDF). Science. 307 (5710): 709–714. Bibcode:2005Sci...307..709W. doi:10.1126/science.1107068. PMID 15661973. Archived (PDF) from the original on 2012-08-13.
  80. ^ Benton, M.J. (March 1983). "Dinosaur Success in the Triassic: a Noncompetitive Ecological Model" (PDF). Quarterly Review of Biology. 58 (1): 29–55. doi:10.1086/413056. Archived from the original (PDF) on September 11, 2008. Retrieved September 8, 2008.
  81. ^ Ruben, J.A. & Jones, T.D. (2000). "Selective Factors Associated with the Origin of Fur and Feathers". American Zoologist. 40 (4): 585–596. doi:10.1093/icb/40.4.585. Archived from the original on 2008-09-06.
  82. ^ Renne, Paul R.; Deino, Alan L.; Hilgen, Frederik J.; Kuiper, Klaudia F.; Mark, Darren F.; Mitchell, William S.; Morgan, Leah E.; Mundil, Roland; Smit, Jan (7 February 2013). "Time Scales of Critical Events Around the Cretaceous-Paleogene Boundary". Science. 339 (6120): 684–687. Bibcode:2013Sci...339..684R. doi:10.1126/science.1230492. PMID 23393261.
  83. ^ Alroy J. (March 1999). "The fossil record of North American mammals: evidence for a Paleocene evolutionary radiation". Systematic Biology. 48 (1): 107–18. doi:10.1080/106351599260472. PMID 12078635.
  84. ^ Simmons, N.B.; Seymour, K.L.; Habersetzer, J. & Gunnell, G.F. (February 2008). "Primitive Early Eocene bat from Wyoming and the evolution of flight and echolocation" (PDF). Nature. 451 (7180): 818–821. Bibcode:2008Natur.451..818S. doi:10.1038/nature06549. PMID 18270539.
  85. ^ J. G. M. Thewissen; S. I. Madar & S. T. Hussain (1996). "Ambulocetus natans, an Eocene cetacean (Mammalia) from Pakistan". Courier Forschungsinstitut Senckenberg. 191: 1–86.
  86. ^ Crane, P.R.; Friis, E.M. & Pedersen, K.R. (2000). "The Origin and Early Diversification of Angiosperms". In Gee, H. (ed.). Shaking the Tree: Readings from Nature in the History of Life. University of Chicago Press. pp. 233–250. ISBN 0-226-28496-4.
  87. ^ Crepet, W.L. (November 2000). "Progress in understanding angiosperm history, success, and relationships: Darwin's abominably "perplexing phenomenon"". Proceedings of the National Academy of Sciences. 97 (24): 12939–12941. Bibcode:2000PNAS...9712939C. doi:10.1073/pnas.97.24.12939. PMC 34068. PMID 11087846.
  88. ^ Wilson, E.O. & Hölldobler, B. (September 2005). "Eusociality: Origin and consequences". Proceedings of the National Academy of Sciences. 102 (38): 13367–13371. Bibcode:2005PNAS..10213367W. doi:10.1073/pnas.0505858102. PMC 1224642. PMID 16157878.
  89. ^ Brunet M., Guy; F., Pilbeam; D., Mackaye, H.T.; et al. (July 2002). "A new hominid from the Upper Miocene of Chad, Central Africa". Nature. 418 (6894): 145–151. doi:10.1038/nature00879. PMID 12110880.CS1 maint: Multiple names: authors list (link)
  90. ^ De Miguel, C. & M. Henneberg, M. (2001). "Variation in hominid brain size: How much is due to method?". HOMO: Journal of Comparative Human Biology. 52 (1): 3–58. doi:10.1078/0018-442X-00019.
  91. ^ Leakey, Richard (1994). The Origin of Humankind. Science Masters Series. New York, NY: Basic Books. pp. 87–89. ISBN 0-465-05313-0.
  92. ^ Benton, M.J. (2004). "6. Reptiles Of The Triassic". Vertebrate Palaeontology. Blackwell. ISBN 0-04-566002-6. Retrieved November 17, 2008.
  93. ^ Van Valkenburgh, B. (1999). "Major patterns in the history of xarnivorous mammals". Annual Review of Earth and Planetary Sciences. 27: 463–493. Bibcode:1999AREPS..27..463V. doi:10.1146/annurev.earth.27.1.463.
  94. ^ a b MacLeod, Norman (2001-01-06). "Extinction!". Archived from the original on April 4, 2008. Retrieved September 11, 2008.
  95. ^ Martin, R.E. (1995). "Cyclic and secular variation in microfossil biomineralization: clues to the biogeochemical evolution of Phanerozoic oceans". Global and Planetary Change. 11 (1): 1. Bibcode:1995GPC....11....1M. doi:10.1016/0921-8181(94)00011-2.
  96. ^ Martin, R.E. (1996). "Secular increase in nutrient levels through the Phanerozoic: Implications for productivity, biomass, and diversity of the marine biosphere". PALAIOS. 11 (3): 209–219. Bibcode:1996Palai..11..209M. doi:10.2307/3515230. JSTOR 3515230.
  97. ^ Gould, S.J. (1990). Wonderful Life: The Burgess Shale and the Nature of History. Hutchinson Radius. pp. 194–206. ISBN 0-09-174271-4.
  98. ^ a b Rohde, R.A. & Muller, R.A. (March 2005). "Cycles in fossil diversity" (PDF). Nature. 434 (7030): 208–210. Bibcode:2005Natur.434..208R. doi:10.1038/nature03339. PMID 15758998. Archived (PDF) from the original on October 3, 2008. Retrieved September 22, 2008.
  99. ^ Rudwick, Martin J.S. (1985). The Meaning of Fossils (2nd ed.). The University of Chicago Press. p. 39. ISBN 0-226-73103-0.
  100. ^ Rudwick, Martin J.S. (1985). The Meaning of Fossils (2nd ed.). The University of Chicago Press. p. 24. ISBN 0-226-73103-0.
  101. ^ Needham, Joseph (1986). Science and Civilization in China: Volume 3, Mathematics and the Sciences of the Heavens and the Earth. Caves Books Ltd. p. 614. ISBN 0-253-34547-2.
  102. ^ a b Baucon, A. 2010. Leonardo da Vinci, the founding father of ichnology. Palaios 25. Abstract available from the author's webpage
  103. ^ Baucon A., Bordy E., Brustur T., Buatois L., Cunningham T., De C., Duffin C., Felletti F., Gaillard C., Hu B., Hu L., Jensen S., Knaust D., Lockley M., Lowe P., Mayor A., Mayoral E., Mikulas R., Muttoni G., Neto de Carvalho C., Pemberton S., Pollard J., Rindsberg A., Santos A., Seike K., Song H., Turner S., Uchman A., Wang Y., Yi-ming G., Zhang L., Zhang W. 2012. A history of ideas in ichnology. In: Bromley R.G., Knaust D. Trace Fossils as Indicators of Sedimentary Environments. Developments in Sedimentology, vol. 64. Tracemaker.com
  104. ^ Baucon, A. 2010. Da Vinci’s Paleodictyon: the fractal beauty of traces. Acta Geologica Polonica, 60(1). Accessible from the author's homepage
  105. ^ McGowan, Christopher (2001). The Dragon Seekers. Persus Publishing. pp. 3–4. ISBN 0-7382-0282-7.
  106. ^ Palmer, D. (2005). Earth Time: Exploring the Deep Past from Victorian England to the Grand Canyon. Wiley. ISBN 9780470022214.
  107. ^ Greene, Marjorie; David Depew (2004). The Philosophy of Biology: An Episodic History. Cambridge University Press. pp. 128–130. ISBN 0-521-64371-6.
  108. ^ Bowler, Peter J.; Iwan Rhys Morus (2005). Making Modern Science. The University of Chicago Press. pp. 168–169. ISBN 0-226-06861-7.
  109. ^ Rudwick, Martin J.S. (1985). The Meaning of Fossils (2nd ed.). The University of Chicago Press. pp. 200–201. ISBN 0-226-73103-0.
  110. ^ Rudwick, Martin J.S. (2008). Worlds Before Adam: The Reconstruction of Geohistory in the Age of Reform. The University of Chicago Press. p. 48. ISBN 978-0-226-73128-5.
  111. ^ a b Buckland W & Gould SJ (1980). Geology and Mineralogy Considered With Reference to Natural Theology (History of Paleontology). Ayer Company Publishing. ISBN 978-0-405-12706-9.
  112. ^ Shu, D. G.; Morris, S. C.; Han, J.; Zhang, Z. F.; Yasui, K.; Janvier, P.; Chen, L.; Zhang, X. L.; Liu, J. N.; Li, Y.; Liu, H. -Q. (2003), "Head and backbone of the Early Cambrian vertebrate Haikouichthys", Nature, 421 (6922): 526–529, Bibcode:2003Natur.421..526S, doi:10.1038/nature01264, PMID 12556891, archived from the original on 2015-11-24
  113. ^ Everhart, Michael J. (2005). Oceans of Kansas: A Natural History of the Western Interior Sea. Indiana University Press. p. 17. ISBN 0-253-34547-2.
  114. ^ Gee, H., ed. (2001). Rise of the Dragon: Readings from Nature on the Chinese Fossil Record. Chicago, Ill. ;London: University of Chicago Press. p. 276. ISBN 0-226-28491-3.
  115. ^ Bowler, Peter J. (2003). Evolution:The History of an Idea. University of California Press. pp. 351–352. ISBN 0-520-23693-9.
  116. ^ Bowler, Peter J. (2003). Evolution:The History of an Idea. University of California Press. pp. 325–339. ISBN 0-520-23693-9.
  117. ^ Crick, F.H.C. (1955). "On degenerate templates and the adaptor hypothesis" (PDF). Archived from the original (PDF) on October 1, 2008. Retrieved October 4, 2008.
  118. ^ Sarich V.M. & Wilson A.C. (December 1967). "Immunological time scale for hominid evolution". Science. 158 (3805): 1200–1203. Bibcode:1967Sci...158.1200S. doi:10.1126/science.158.3805.1200. PMID 4964406.
  119. ^ Page, R.D.M & Holmes, E.C. (1998). Molecular Evolution: A Phylogenetic Approach. Oxford: Blackwell Science. p. 2. ISBN 0-86542-889-1.

External links

Diplodocus

Diplodocus (, , or ) is a genus of diplodocid sauropod dinosaurs whose fossils were first discovered in 1877 by S. W. Williston. The generic name, coined by Othniel Charles Marsh in 1878, is a neo-Latin term derived from Greek διπλός (diplos) "double" and δοκός (dokos) "beam", in reference to the double-beamed chevron bones located in the underside of the tail, which were then considered unique. It is now common scientific opinion that Seismosaurus hallorum is a species of Diplodocus.

This genus of dinosaurs lived in what is now mid-western North America at the end of the Jurassic period. Diplodocus is one of the more common dinosaur fossils found in the middle to upper Morrison Formation, between about 154 and 152 million years ago, during the late Kimmeridgian age. The Morrison Formation records an environment and time dominated by gigantic sauropod dinosaurs, such as Apatosaurus, Barosaurus, Brachiosaurus, Brontosaurus, and Camarasaurus. Its great size may have been a deterrent to the predators Allosaurus and Ceratosaurus: their remains have been found in the same strata, which suggests that they coexisted with Diplodocus.

Diplodocus is among the most easily identifiable dinosaurs, with its typical sauropod shape, long neck and tail, and four sturdy legs. For many years, it was the longest dinosaur known.

Fossilworks

Fossilworks is a portal which provides query, download, and analysis tools to facilitate access to the Paleobiology Database, a large relational database assembled by hundreds of paleontologists from around the world.

History of paleontology

The history of paleontology traces the history of the effort to understand the history of life on Earth by studying the fossil record left behind by living organisms. Since it is concerned with understanding living organisms of the past, paleontology can be considered to be a field of biology, but its historical development has been closely tied to geology and the effort to understand the history of Earth itself.

In ancient times, Xenophanes (570–480 BC), Herodotus (484–425 BC), Eratosthenes (276–194 BC), and Strabo (64 BC-24 AD) wrote about fossils of marine organisms, indicating that land was once under water. During the Middle Ages, fossils were discussed by Persian naturalist Ibn Sina (known as Avicenna in Europe) in The Book of Healing (1027), which proposed a theory of petrifying fluids that Albert of Saxony would elaborate on in the 14th century. The Chinese naturalist Shen Kuo (1031–1095) would propose a theory of climate change based on evidence from petrified bamboo.

In early modern Europe, the systematic study of fossils emerged as an integral part of the changes in natural philosophy that occurred during the Age of Reason. The nature of fossils and their relationship to life in the past became better understood during the 17th and 18th centuries, and at the end of the 18th century, the work of Georges Cuvier had ended a long running debate about the reality of extinction, leading to the emergence of paleontology- in association with comparative anatomy- as a scientific discipline. The expanding knowledge of the fossil record also played an increasing role in the development of geology, and stratigraphy in particular.

In 1822, the word "paleontology" was used by the editor of a French scientific journal to refer to the study of ancient living organisms through fossils, and the first half of the 19th century saw geological and paleontological activity become increasingly well organized with the growth of geologic societies and museums and an increasing number of professional geologists and fossil specialists. This contributed to a rapid increase in knowledge about the history of life on Earth, and progress towards definition of the geologic time scale largely based on fossil evidence. As knowledge of life's history continued to improve, it became increasingly obvious that there had been some kind of successive order to the development of life. This would encourage early evolutionary theories on the transmutation of species. After Charles Darwin published Origin of Species in 1859, much of the focus of paleontology shifted to understanding evolutionary paths, including human evolution, and evolutionary theory.The last half of the 19th century saw a tremendous expansion in paleontological activity, especially in North America. The trend continued in the 20th century with additional regions of the Earth being opened to systematic fossil collection, as demonstrated by a series of important discoveries in China near the end of the 20th century. Many transitional fossils have been discovered, and there is now considered to be abundant evidence of how all classes of vertebrates are related, much of it in the form of transitional fossils. The last few decades of the 20th century saw a renewed interest in mass extinctions and their role in the evolution of life on Earth. There was also a renewed interest in the Cambrian explosion that saw the development of the body plans of most animal phyla. The discovery of fossils of the Ediacaran biota and developments in paleobiology extended knowledge about the history of life back far before the Cambrian.

Journal of Paleontology

The Journal of Paleontology is a peer-reviewed scientific journal covering the field of paleontology. It is published by the Paleontological Society.

Journal of Vertebrate Paleontology

The Journal of Vertebrate Paleontology is a bimonthly peer-reviewed scientific journal that was established in 1980 by Jiri Zidek (University of Oklahoma). It covers all aspects of vertebrate paleontology, including vertebrate origins, evolution, functional morphology, taxonomy, biostratigraphy, paleoecology, paleobiogeography, and paleoanthropology. The journal is published by Taylor & Francis on behalf of the Society of Vertebrate Paleontology. According to the Journal Citation Reports, the journal has a 2017 impact factor of 2.190.

La Brea Tar Pits

La Brea Tar Pits are a group of tar pits around which Hancock Park was formed in urban Los Angeles. Natural asphalt (also called asphaltum, bitumen, pitch, or tar—brea in Spanish) has seeped up from the ground in this area for tens of thousands of years. The tar is often covered with dust, leaves, or water. Over many centuries, the tar preserved the bones of trapped animals. The George C. Page Museum is dedicated to researching the tar pits and displaying specimens from the animals that died there. La Brea Tar Pits are a registered National Natural Landmark.

List of years in paleontology

The following entries cover events related to the study of paleontology which occurred in the listed year.

1600s - 1700s - 1800s - 1900s- 2000s

Neontology

Neontology is a part of biology that, in contrast to paleontology, deals with living (or, more generally, recent) organisms. It is the study of extant taxa (singular: extant taxon): taxa (such as species, genera and families) with members still alive, as opposed to (all) being extinct. For example:

The moose (Alces alces) is an extant species, and the dodo (Raphus cucullatus) is an extinct species.

In the group of molluscs known as the cephalopods, as of 1987 there were approximately 600 extant species and 7,500 extinct species.A taxon can be classified as extinct if it is broadly agreed or certified that no members of the group are still alive. Conversely, an extinct taxon can be reclassified as extant if there are new discoveries of extant species ("Lazarus species"), or if previously-known extant species are reclassified as members of the taxon.

Most biologists, zoologists, and botanists are in practice neontologists, and the term neontologist is used largely by paleontologists referring to non-paleontologists. Stephen Jay Gould said of neontology:

All professions maintain their parochialisms, and I trust that nonpaleontological readers will forgive our major manifestation. We are paleontologists, so we need a name to contrast ourselves with all you folks who study modern organisms in human or ecological time. You therefore become neontologists. We do recognize the unbalanced and parochial nature of this dichotomous division.

Neontological evolutionary biology has a temporal perspective between 100 to 1000 years. Neontology's fundamental basis relies on models of natural selection as well as speciation. Neontology's methods, when compared to evolutionary paleontology, has a greater emphasis on experiments. There are more frequent discontinuities present in paleontology than in neontology, because paleontology involves extinct taxa. Neontology has organisms actually present and available to sample and perform research on. Neontology's research method uses cladistics to examine morphologies and genetics. Neontology data has more emphasis on genetic data and the population structure than paleontology does.

Old Red Sandstone

The Old Red Sandstone is an assemblage of rocks in the North Atlantic region largely of Devonian age. It extends in the east across Great Britain, Ireland and Norway, and in the west along the northeastern seaboard of North America. It also extends northwards into Greenland and Svalbard. In Britain it is a lithostratigraphic unit (a sequence of rock strata) to which stratigraphers accord supergroup status and which is of considerable importance to early palaeontology. For convenience the short version of the term, ORS is often used in literature on the subject. The term was coined to distinguish the sequence from the younger New Red Sandstone which also occurs widely throughout Britain.

Paleobiology Database

The Paleobiology Database is an online resource for information on the distribution and classification of fossil animals, plants, and microorganisms.

Paleobotany

Paleobotany, also spelled as palaeobotany, is the branch of botany dealing with the recovery and identification of plant remains from geological contexts, and their use for the biological reconstruction of past environments (paleogeography), and the evolutionary history of plants, with a bearing upon the evolution of life in general. A synonym is paleophytology. It is a component of paleontology and paleobiology. The prefix palaeo- means "ancient, old", and is derived from the Greek adjective παλαιός, palaios. Paleobotany includes the study of terrestrial plant fossils, as well as the study of prehistoric marine photoautotrophs, such as photosynthetic algae, seaweeds or kelp. A closely related field is palynology, which is the study of fossilized and extant spores and pollen.

Paleobotany is important in the reconstruction of ancient ecological systems and climate, known as paleoecology and paleoclimatology respectively; and is fundamental to the study of green 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.

The emergence of paleobotany as a scientific discipline can be seen in the early 19th century, especially in the works of the German palaeontologist Ernst Friedrich von Schlotheim, the Czech (Bohemian) nobleman and scholar Kaspar Maria von Sternberg, and the French botanist Adolphe-Théodore Brongniart.

Paleoecology

Paleoecology (also spelled palaeoecology) is the study of interactions between organisms and/or interactions between organisms and their environments across geologic timescales. As a discipline, paleoecology interacts with, depends on and informs a variety of fields including paleontology, ecology, climatology and biology.

Paleoecology emerged from the field of paleontology in the 1950s, though paleontologists have conducted paleoecological studies since the creation of paleontology in the 1700s and 1800s. Combining the investigative approach of searching for fossils with the theoretical approach of Charles Darwin and Alexander von Humboldt, paleoecology began as paleontologists began examining both the ancient organisms they discovered and the reconstructed environments in which they lived. Visual depictions of past marine and terrestrial communities has been considered an early form of paleoecology.

Paleontology in Colorado

Paleontology in Colorado refers to paleontological research occurring within or conducted by people from the U.S. state of Colorado.

The geologic column of Colorado spans about one third of Earth's history. Fossils can be found almost everywhere in the state but are not evenly distributed among all the ages of the state's rocks. During the early Paleozoic, Colorado was covered by a warm shallow sea that would come to be home to creatures like brachiopods, conodonts, ostracoderms, sharks and trilobites. This sea withdrew from the state between the Silurian and early Devonian leaving a gap in the local rock record. It returned during the Carboniferous. Areas of the state not submerged were richly vegetated and inhabited by amphibians that left behind footprints that would later fossilize. During the Permian, the sea withdrew and alluvial fans and sand dunes spread across the state. Many trace fossils are known from these deposits.

The sea returned during the Triassic, while exposed areas were a richly vegetated coastal plain that was home to dinosaurs. Colorado was again submerged by a sea during the Cretaceous period that was home to plesiosaurs up to 70 feet long. During the early part of the Cenozoic era, rainforests grew in Colorado. Later, another rich flora and fauna would come to be preserved in the Florissant beds, where both rhinoceroses and uintatheres lived. More recently the state's modern prairies began to form and the state was home to creatures like bison, camels, horses, and mammoths. Local Native Americans have devised myths to explain local fossil bones and dinosaur footprints. By the late 19th century, local fossils had attracted the attention of formally trainer scientists. Major finds include the Late Jurassic dinosaurs of the Morrison Formation and the Cenozoic plants and mammals of the Florissant beds. The Jurassic plated dinosaur Stegosaurus armatus is the Colorado state fossil. Stegosaurus is also the state dinosaur of Colorado.

Paleontology in the United States

Paleontology in the United States refers to paleontological research occurring within or conducted by people from the United States. Paleontologists have found that at the start of the Paleozoic era, what is now "North" America was actually in the southern hemisphere. Marine life flourished in the country's many seas. Later the seas were largely replaced by swamps, home to amphibians and early reptiles. When the continents had assembled into Pangaea drier conditions prevailed. The evolutionary precursors to mammals dominated the country until a mass extinction event ended their reign.

The Mesozoic era followed and the dinosaurs began their rise to dominance, spreading into the country before Pangaea split up. During the latter Jurassic Morrison Formation dinosaurs lived in the western states. During the Cretaceous, the Gulf of Mexico expanded until it split North America in half. Plesiosaurs and mosasaurs swam in its waters. Later it began to withdraw and the western states were home to the Hell Creek dinosaurs. Another mass extinction ended the reign of the dinosaurs.

The Cenozoic era began afterward. The inland sea of the Cretaceous vanished and mammals came to dominate the land. The western states were home to primitive camels and horses as well as the carnivorous creodonts. Soon mammals had entered the oceans and the early whale Basilosaurus swam the coastal waters of the southeast. Rhino-like titanotheres dominated Oligocene South Dakota. From this point on the climate in the United States cooled until the Pleistocene, when glaciers spread. Saber-toothed cats, woolly mammoths, mastodons, and dire wolves roamed the land. Humans arrived across a land bridge between Siberia and Alaska and may have played a role in hunting these animals into extinction.

Native Americans have been familiar with fossils for thousands of years, but the first major fossil discovery to attract the attention of formally trained scientists were the Ice Age fossils of Kentucky's Big Bone Lick. These fossils were studied by eminent intellectuals like France's George Cuvier and local statesmen like Benjamin Franklin, Thomas Jefferson, and George Washington. By the beginning of the 19th century, Dinosaur footprints were discovered near the country's east coast. Later in the century, as more dinosaur fossils were uncovered, eminent paleontologists Edward Drinker Cope and Othniel Charles Marsh were embroiled in a bitter rivalry to collect the most fossils and name the most new species.

Early in the 20th century major finds continued, such as the Ice Age mammals of the La Brea Tar Pits. Mid-to-late twentieth-century discoveries in the United States triggered the Dinosaur Renaissance as the discovery of the bird-like Deinonychus overturned misguided notions of dinosaurs as plodding lizard-like animals, highlighting their sophisticated physiology and apparent relationship with birds. Other notable finds in the United States include Maiasaura, which provided early evidence for parental care in dinosaurs and "Seismosaurus", the largest known dinosaur.

Paleornithology

Paleornithology also known as Avian Paleontology is the scientific study of bird evolution and fossil birds. It is a mix of ornithology and paleontology. Paleornithology began with the discovery of Archaeopteryx. The reptilian relationship of birds and their ancestors, the theropod dinosaurs, are important aspects of paleornithological research. Other areas of interest to paleornithologists are the early sea-birds Ichthyornis, Hesperornis, and others. Notable paleornithologists are Storrs L. Olson, Alexander Wetmore, Alan Feduccia, Cécile Mourer-Chauviré, Philip Ashmole, Pierce Brodkorb, Trevor H. Worthy, Zhou Zhonghe, Yevgeny Kurochkin, Bradley C. Livezey, Gareth J. Dyke, Luis M. Chiappe, Gerald Mayr and David Steadman.

Royal Tyrrell Museum of Palaeontology

The Royal Tyrrell Museum is a Canadian tourist attraction and a centre of palaeontological research known for its collection of more than 130,000 fossils.Located 6 km (4 mi) northwest from Drumheller, Alberta and 135 km (84 mi) northeast from Calgary, the museum is situated in the middle of the fossil-bearing strata of the Late Cretaceous Horseshoe Canyon Formation and holds numerous specimens from the Alberta badlands, Dinosaur Provincial Park and the Devil's Coulee Dinosaur Egg Site.The Royal Tyrrell Museum is operated by Alberta's Ministry of Culture.

Treatise on Invertebrate Paleontology

The Treatise on Invertebrate Paleontology (or TIP) published by the Geological Society of America and the University of Kansas Press, is a definitive multi-authored work of some 50 volumes, written by more than 300 paleontologists, and covering every phylum, class, order, family, and genus of fossil and extant (still living) invertebrate animals. The prehistoric invertebrates are described as to their taxonomy, morphology, paleoecology, stratigraphic and paleogeographic range. However, genera with no fossil record whatsoever have just a very brief listing.

Publication of the decades-long Treatise on Invertebrate Paleontology is a work-in-progress; and therefore it is not yet complete: For example, there is no volume yet published regarding the post-Paleozoic era caenogastropods (a molluscan group including the whelk and periwinkle). Furthermore, every so often, previously published volumes of the Treatise are revised.

Triceratops

Triceratops is a genus of herbivorous ceratopsid dinosaur that first appeared during the late Maastrichtian stage of the late Cretaceous period, about 68 million years ago (mya) in what is now North America. It is one of the last known non-avian dinosaur genera, and became extinct in the Cretaceous–Paleogene extinction event 66 million years ago. The name Triceratops, which literally means "three-horned face", is derived from the Ancient Greek words τρί- (tri-) meaning "three", κέρας (kéras) meaning "horn", and ὤψ (ōps) meaning "face".

Triceratops has been documented by numerous remains collected since the genus was first described in 1889 by Othniel Charles Marsh. Specimens representing life stages from hatchling to adult have been found. As the archetypal ceratopsid, Triceratops is one of the most popular dinosaurs, and has been featured in film, postal stamps, and many other types of media.

Bearing a large bony frill and three horns on the skull, and its large four-legged body possessing similarities with the modern rhinoceros, Triceratops is one of the most recognizable of all dinosaurs and the best known ceratopsid. It was also one of the largest, up to nine metres long and twelve tonnes in weight. It shared the landscape with and was probably preyed upon by Tyrannosaurus, though it is less certain that the two did battle in the manner often depicted in museum displays and popular images. The functions of the frills and three distinctive facial horns on its head have long inspired debate. Traditionally, these have been viewed as defensive weapons against predators. More recent interpretations find it probable that these features were primarily used in species identification, courtship and dominance display, much like the antlers and horns of modern species.

Triceratops was traditionally placed within the "short-frilled" ceratopsids but modern cladistic studies show it to be a member of the Chasmosaurinae which usually have long frills. Two species, T. horridus and T. prorsus, are considered valid today, from the seventeen species that have ever been named. Research published in 2010 concluded that the contemporaneous Torosaurus, a ceratopsid long regarded as a separate genus, represents Triceratops in its mature form. This view was immediately disputed with examination of more fossil evidence needed to settle the debate.

Tyrannosaurus

Tyrannosaurus is a genus of coelurosaurian theropod dinosaur. The species Tyrannosaurus rex (rex meaning "king" in Latin), often called T. rex or colloquially T-Rex, is one of the most well-represented of the large theropods. Tyrannosaurus lived throughout what is now western North America, on what was then an island continent known as Laramidia. Tyrannosaurus had a much wider range than other tyrannosaurids. Fossils are found in a variety of rock formations dating to the Maastrichtian age of the upper Cretaceous Period, 68 to 66 million years ago. It was the last known member of the tyrannosaurids, and among the last non-avian dinosaurs to exist before the Cretaceous–Paleogene extinction event.

Like other tyrannosaurids, Tyrannosaurus was a bipedal carnivore with a massive skull balanced by a long, heavy tail. Relative to its large and powerful hind limbs, Tyrannosaurus forelimbs were short but unusually powerful for their size and had two clawed digits. The most complete specimen measures up to 12.3 m (40 ft) in length though T. rex could grow to lengths of over 12.3 m (40 ft), up to 3.66 meters (12 ft) tall at the hips, and according to most modern estimates 8.4 metric tons (9.3 short tons) to 14 metric tons (15.4 short tons) in weight. Although other theropods rivaled or exceeded Tyrannosaurus rex in size, it is still among the largest known land predators and is estimated to have exerted the strongest bite force among all terrestrial animals. By far the largest carnivore in its environment, Tyrannosaurus rex was most likely an apex predator, preying upon hadrosaurs, armored herbivores like ceratopsians and ankylosaurs, and possibly sauropods. Some experts have suggested the dinosaur was primarily a scavenger. The question of whether Tyrannosaurus was an apex predator or a pure scavenger was among the longest debates in paleontology. Most paleontologists today accept that Tyrannosaurus was both an active predator and a scavenger.

More than fifty major specimens of Tyrannosaurus rex have been identified, some of which are nearly complete skeletons. Soft tissue and proteins have been reported in at least one of these specimens. The abundance of fossil material has allowed significant research into many aspects of its biology, including its life history and biomechanics. The feeding habits, physiology and potential speed of Tyrannosaurus rex are a few subjects of debate. Its taxonomy is also controversial, as some scientists consider Tarbosaurus bataar from Asia to be a second Tyrannosaurus species while others maintain Tarbosaurus is a separate genus. Several other genera of North American tyrannosaurids have also been synonymized with Tyrannosaurus.

As the archetypal theropod, Tyrannosaurus has been one of the best-known dinosaurs since the early 20th century, and has been featured in film, advertising, postal stamps, and many other media.

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