Movebot at 17:46, 31 July 2022

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[[File:Amonite Cropped.jpg|thumb|230px|Three small [[ammonite]] fossils, each about 1.5 cm across]]
[[File:Trilobite2.jpg|thumb|230px|A fossil of a [[trilobite]] which lived about 444 million years ago]]
[[File:Stromatolites Cochabamba.jpg|thumb|right|230px| Lower [[Proterozoic]] [[stromatolites]] from [[Bolivia]], South America. These were produced by [[cyanobacteria]]. Polished vertical slice through rock]]
[[File:Insects in baltic amber.jpg|thumb|230px|A [[mosquito]] and a [[fly]] trapped in [[amber]]]]
[[File:Cretaceous Orthoptera fossil.jpg|thumb|right|230px|Fossil [[locust]] from the earliest [[Upper Cretaceous]], ~95 million years ago, [[Santana Formation]], [[Brazil]]]]

A '''fossil''' is the remains or trace of an ancient living thing.<ref>Fossil: the remains or impression of a prehistoric plant or animal, usually petrified (turned into stone) while embedded in rock". ''Concise Oxford Dictionary'', 9th ed.</ref>

Fossils of [[animal]]s, [[plant]]s, or [[protist]]s occur in [[sedimentary rock]].

In a typical fossil, the body form is retained, but the original [[molecule]]s that made up the body have been replaced by some [[Inorganic matter|inorganic]] material, such as [[calcium carbonate]] (CaCO3) or [[silica]] (SiO2). The fossil feels like, and is, made of [[Rock (geology)|rock]]. It has been [[mineralization|mineralised]] or ''petrified'' (literally, turned into rock).

A fossil may also be an ''imprint'' or ''impression'' of a living thing remaining in the fossilised [[mud]] of a long-gone age.

Some [[organism]]s fossilise well, others do not. The most common fossils are those left behind by organisms that produce hard materials. The hard, [[Calcite|calcitic]] shells of [[mollusc]]s (such as [[clam]]s and [[snail]]s) and of now-rare [[brachiopod]]s (also known as lampshells) are examples. These sea-dwelling [[shellfish]] have produced many fossiliferous (that is, fossil-bearing) [[chalk]]y [[strata|layers]] of [[limestone]] in the earth.

Soft-bodied organisms can fossilise in special circumstances: the [[Ediacaran biota]] is a good example.<ref>Levin, Harold. 2006. ''The Earth though time''. 8th ed, Wiley N.Y. Chapter 6, p117.</ref>

The best-known fossils for the general public are those of the giant, [[prehistoric]] [[dinosaur]]s. The fossilized [[bone]]s and fossilized [[Animal tracks|tracks]] of these huge, [[Ancient history|ancient]] [[reptile]]s can be seen in many [[museum]]s of [[natural history]] and [[earth science]].

The study of fossils by [[geologist]]s and [[biologist]]s is known as [[paleontology]]. If the study puts living things in their [[ecology|ecological]] context it is called [[paleobiology]].

Examples of fossils include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood, oil, coal, and DNA remnants.

== Human uses ==

Humans have found many uses for fossils. Some fossils are found and sold for money, in Morocco, fossils of ammonites, dinosaurs and sharks are examples of such. Other fossils like those in the [[Tamiami formation]] are used in the construction of roads. In some places fossils are used as a mulch- material used to cover soil. Some fossils are used as a marker to determine formation .

Some fossils are used as a source of fuel, these fossils are referred to as a [[fossil fuel]].

== Places of special preservation ==
There are some sites where fossils have been found with remarkable details, or in large numbers. Palaeontologists call these sites by the German term ''[[Lagerstätte]]n''. The [[La Brea tar pits]] in [[Los Angeles]] is such a place. So are the [[Solnhofen limestone]] [[quarry|quarries]] in [[Bavaria]].

A very important place is the [[Burgess Shale]], known for its many important finds

== Types of fossils ==
[[Microscopic]] or ''very tiny'' fossils are called "microfossils"; while larger, ''[[macroscopic]]'' fossils — such as those of [[mollusc|seashells]] and [[mammal]]s — are called "macrofossils". [[Natural]] [[stone]]s which look like fossilized [[organism]]s, but are not fossils at all, are called "pseudofossils".

Although most fossils are formed from the hard parts of organisms, there are also ''indirect'' [[signs]] of prehistoric life. Examples such as a [[worm]]'s [[trail]] or an animal's footprint are quite common. They are known as ''[[trace fossil]]s''. Fossilized [[excrement]], [[faeces]] or dung is known as a ''coprolite''. [[Chemical]] traces of prehistoric organisms is called a ''chemofossil''. Objects made by prehistoric people are called [[Artifact (archaeology)|artifacts]].

Even when the remains of soft-bodied animals are gone, there may be impressions, molds or [[carbon]] traces which remain permanently. So, in special cases, we do have fossils even of small, soft invertebrate animals.

Sometimes a fossil is produced as a result of dryness ([[desiccation]]), [[freezing]], or [[pine]] [[resin]]. [[Mummy|Mummified animals]], [[ice]]-covered wooly [[mammoth]]s, and [[insect]]-filled [[amber]] are examples of such fossils.

[[Living fossil]]s, however, are ''not'' fossils at all. Instead, they are modern-day organisms which very closely resemble their prehistoric [[ancestor]]s of many millions of years ago. The [[ginkgo]] [[tree]], the [[coelacanth]] and the [[horseshoe crab]] are good examples.

== Early notice taken of fossils ==
Many pre-scientific peoples noticed fossils, but not all thought they were the remains of living things. Perhaps the first to leave a record of his thought was the [[Ancient Greek]] [[philosopher]] [[Xenophanes]] (about 570BC–470BC).<ref>Guthrie W.K.C. 1962. ''A history of Greek philosophy''. vol 1: The earlier [[presocratic]]s and the [[pythagoreans]]. Cambridge.</ref>p387 His ideas were reported by later writers:
:"Shells [are] found in the midst of the land, and on mountains. In the [[quarry|quarries]] of [[Syracuse, Italy|Syracuse]] the impressions of a fish and seaweed have been found; on [[Paros]] the impression of a bay-leaf in the depth of a stone, and on [[Malta]] the flattened shape of sea-creatures [have been found]. These, he says, were formed when everything, long ago, was covered in mud, and the impression dried out in the mud". Guthrie p387

These ideas were rediscovered in the 17th century in Europe. [[Nicolas Steno]] in the [[Netherlands]] and [[Robert Hooke]] at the [[Royal Society]] in [[London]] both wrote and gave lectures about fossils. In the 18th century fossil-collecting began, and serious thinking on [[geology]] began to make progress. In the 19th century geology became a modern science, and fossils played a part in the theory of [[evolution]].

== Related pages ==
* [[Extinction]]
* [[Evolution]]
* [[Palaeontology]]
* [[Earth history]]
* [[List of extinction events]]
* [[Lagerstätten]]

== Other websites ==
{{Commons category|Fossils}}
* [http://en.citizendium.org/wiki/Fossil Fossil] -Citizendium

== References ==
{{Reflist}}

[[Category:Paleontology]]
[[Category:Fossils|*]]

Fossil - Revision history

Movebot at 17:46, 31 July 2022