Fossil
Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood and DNA remnants.The development of radiometric dating techniques in the early 20th century allowed scientists to quantitatively measure the absolute ages of rocks and the fossils they host.There are many examples of paleolithic stone knives in Europe, with fossil echinoderms set precisely at the hand grip, dating back to Homo heidelbergensis and Neanderthals.Pliny also makes one of the earlier known references to toadstones, thought until the 18th century to be a magical cure for poison originating in the heads of toads, but which are fossil teeth from Lepidotes, a Cretaceous ray-finned fish.[21] There is no such direct mythological connection known from prehistoric Africa, but there is considerable evidence of tribes there excavating and moving fossils to ceremonial sites, apparently treating them with some reverence.[22] In Japan, fossil shark teeth were associated with the mythical tengu, thought to be the razor-sharp claws of the creature, documented some time after the 8th century AD.One good example is the famous scholar Huang Tingjian of the Song dynasty during the 11th century, who kept a specific seashell fossil with his own poem engraved on it.[23] In his Dream Pool Essays published in 1088, Song dynasty Chinese scholar-official Shen Kuo hypothesized that marine fossils found in a geological stratum of mountains located hundreds of miles from the Pacific Ocean was evidence that a prehistoric seashore had once existed there and shifted over centuries of time.After observing the existence of seashells in mountains, the ancient Greek philosopher Xenophanes (c. 570 – 478 BC) speculated that the world was once inundated in a great flood that buried living creatures in drying mud.[15] These grew into the shepherd's crowns of English folklore, used for decoration and as good luck charms, placed by the doorway of homes and churches.Near the end of his 1796 paper on living and fossil elephants he said: All of these facts, consistent among themselves, and not opposed by any report, seem to me to prove the existence of a world previous to ours, destroyed by some kind of catastrophe.[40] Early naturalists well understood the similarities and differences of living species leading Linnaeus to develop a hierarchical classification system still in use today.When Darwin wrote On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life, the oldest animal fossils were those from the Cambrian Period, now known to be about 540 million years old.The fossil record is life's evolutionary epic that unfolded over four billion years as environmental conditions and genetic potential interacted in accordance with natural selection."[44] Molecular biologists, using phylogenetics, can compare protein amino acid or nucleotide sequence homology (i.e., similarity) to evaluate taxonomy and evolutionary distances among organisms, with limited statistical confidence.Synchrotron X-ray tomographic analysis of early Cambrian bilaterian embryonic microfossils yielded new insights of metazoan evolution at its earliest stages.Fossils of two enigmatic bilaterians, the worm-like Markuelia and a putative, primitive protostome, Pseudooides, provide a peek at germ layer embryonic development.[jargon] This research is a notable example of how knowledge encoded by the fossil record continues to contribute otherwise unattainable information on the emergence and development of life on Earth.For example, the research suggests Markuelia has closest affinity to priapulid worms, and is adjacent to the evolutionary branching of Priapulida, Nematoda and Arthropoda.[86][87][88][89] In 2014, Mary Schweitzer and her colleagues reported the presence of iron particles (goethite-aFeO(OH)) associated with soft tissues recovered from dinosaur fossils.Microfossils may either be complete (or near-complete) organisms in themselves (such as the marine plankters foraminifera and coccolithophores) or component parts (such as small teeth or spores) of larger animals or plants.Microfossils are of critical importance as a reservoir of paleoclimate information, and are also commonly used by biostratigraphers to assist in the correlation of rock units.Fossil resin (colloquially called amber) is a natural polymer found in many types of strata throughout the world, even the Arctic.[104] The main importance of subfossil vs. fossil remains is that the former contain organic material, which can be used for radiocarbon dating or extraction and sequencing of DNA, protein, or other biomolecules.[12][13]Stromatolites are layered accretionary structures formed in shallow water by the trapping, binding and cementation of sedimentary grains by biofilms of microorganisms, especially cyanobacteria.The most widely supported explanation is that stromatolite builders fell victims to grazing creatures (the Cambrian substrate revolution), implying that sufficiently complex organisms were common over 1 billion years ago.[118] While prokaryotic cyanobacteria themselves reproduce asexually through cell division, they were instrumental in priming the environment for the evolutionary development of more complex eukaryotic organisms.Cyanobacteria (as well as extremophile Gammaproteobacteria) are thought to be largely responsible for increasing the amount of oxygen in the primeval Earth's atmosphere through their continuing photosynthesis.In modern microbial mats, debris from the surrounding habitat can become trapped within the mucus, which can be cemented by the calcium carbonate to grow thin laminations of limestone.[121][122] According to one hypothesis, a Corinthian vase from the 6th century BCE is the oldest artistic record of a vertebrate fossil, perhaps a Miocene giraffe combined with elements from other species.[125] However, a subsequent study using artificial intelligence and expert evaluations reject this idea, because mammals do not have the eye bones shown in the painted monster.
Dinosaur BonesFossil (disambiguation)Fossilization (linguistics)OnychocrinusPalaeosinopaGryphaeaHarpactocarcinusClassical Latingeological ageshellsexoskeletonsmicrobespetrified woodTiktaalikCanadaPaleontologyevolutionarystratageological timescalerelative agesradiometric datingabsolute agespermineralizationauthigenic mineralizationcarbonizationmicrometredinosaursmineralizedvertebrateschitinouscalcareousinvertebratesanimal trackscoprolitestrace fossilsbiochemicalbiosignaturesTrace fossilMicrofossilFossil preparationIndex fossilList of fossilsList of fossil sitesLagerstätte fossil bedsList of transitional fossilsList of human evolution fossilsBiogeographyExtinction eventGeochronologyGeologic time scaleGeologic recordHistory of lifeOrigin of lifePaleoclimatologyTimeline of evolutionTransitional fossilAvian flightMulticellsFlagellaMammalian auditory ossiclesMosaic evolutionNervous systemsButterfliesCephalopodsCetaceansFishesHumansInsectsMammalsMolluscsPlantsReptilesSea cowsSpidersIntroduction to evolutionCommon descentPhylogenyCladisticsBiological classificationHistory of paleontologyTimeline of paleontologyBiostratigraphyIchnologyInvertebrate paleontologyMicropaleontologyMolecular paleontologyPalaeoxylologyPaleobiologyPaleobotanyPaleoecologyPaleogeneticsPaleolimnologyPaleomycologyPaleoneurobiologyPaleopathologyPaleopedologyPaleotempestologyPaleozoologyPalynologySclerochronologyTaphonomyVertebrate paleontologyevolutionhistory of life on EarthPaleontologistsspeciesDzungarian GatepaleolithicechinodermsHomo heidelbergensisNeanderthalshippopotamuscretaceousMicrasterHerodotosHyperboreagryphonsProtoceratopsAristotlevaporousexhalationsPersianAvicennapetrifyingfluidsAlbert of Saxony