Fossil
hideFossils (from Latin fossus, literally "having been dug up") are the preserved remains or traces of animals, plants, and other organisms from the remote past. The totality of fossils, both discovered and undiscovered, and their placement in fossiliferous (fossil-containing) rock formations and sedimentary layers (strata) is known as the fossil record. The study of fossils across geological time, how they were formed, and the evolutionary relationships between taxa (phylogeny) are some of the most important functions of the science of paleontology. Such a preserved specimen is called a "fossil" if it is older than some minimum age, most often the arbitrary date of 10,000 years ago. Hence, fossils range in age from the youngest at the start of the Holocene Epoch to the oldest from the Archaean Eon several billion years old. The observations that certain fossils were associated with certain rock strata led early geologists to recognize a geological timescale in the 19th century. The development of radiometric dating techniques in the early 20th century allowed geologists to determine the numerical or "absolute" age of the various strata and thereby the included fossils.
Like extant organisms, fossils vary in size from microscopic, such as single bacterial cells only one micrometer in diameter, to gigantic, such as dinosaurs and trees many meters long and weighing many tons. A fossil normally preserves only a portion of the deceased organism, usually that portion that was partially mineralized during life, such as the bones and teeth of vertebrates, or the chitinous exoskeletons of invertebrates. Preservation of soft tissues is rare in the fossil record. Fossils may also consist of the marks left behind by the organism while it was alive, such as the footprint or feces (coprolites) of a reptile. These types of fossil are called trace fossils (or ichnofossils), as opposed to body fossils. Finally, past life leaves some markers that cannot be seen but can be detected in the form of biochemical signals; these are known as chemofossils or biomarkers.
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News tagged with fossil
Researchers engineer bacteria to turn carbon dioxide into liquid fuel
1hour ago |
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(PhysOrg.com) -- The genetically modified cyanobacterium consumes carbon dioxide and produces the liquid fuel isobutanol by using energy from sunlight.
Early carnivorous dinosaurs crossed continents
Other Sciences / Archaeology & Fossils
2 hours ago |
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Did the first dinosaurs wander across continents or stay put where they first evolved? The first dinosaurs evolved 230 million years ago when the continents were assembled into one landmass called Pangea. ...
Fossils shake dinosaur family tree
Other Sciences / Archaeology & Fossils
5 hours ago |
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(PhysOrg.com) -- Paleontologists have unearthed a previously unknown meat-eating dinosaur in New Mexico, settling a debate about early dinosaur evolution, revealing a period of explosive diversification and ...
Flying dinosaur controversy resolved
Other Sciences / Archaeology & Fossils
7 hours ago |
3.3 / 5 (9) |
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(PhysOrg.com) -- New research appears to have ended a scientific debate that has vexed palaeontologists for almost 100 years.
DNA study sheds new light on horse evolution
9 hours ago |
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(PhysOrg.com) -- Ancient DNA retrieved from extinct horse species from around the world has challenged one of the textbook examples of evolution - the fossil record of the horse family Equidae over the past ...
Earliest toothless bird found
Other Sciences / Archaeology & Fossils
10 hours ago |
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(PhysOrg.com) -- A new species of bird from the Cretaceous period in China has been identified. It had toothless upper and lower jaws, and provides significant information on the diversification in the evolution ...
Tropical birds waited for land crossing between North and South America: study
Dec 09, 2009 |
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Despite their ability to fly, tropical birds waited until the formation of the land bridge between North and South America to move northward, according to a University of British Columbia study published this ...
New technology helps scientists understand ancient fossils
Other Sciences / Archaeology & Fossils
Dec 07, 2009 |
5 / 5 (1) |
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Some of the world's oldest human bones and other ancient relics are studied here using some of the world's newest technologies.
192 nations at UN climate conference in Copenhagen
Dec 07, 2009 |
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(AP) -- The largest and most important U.N. climate change conference in history opened Monday, with organizers warning diplomats from 192 nations that this could be the best, last chance for a deal to protect ...
