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
Antarctica served as climatic refuge in Earth's greatest extinction event
Space & Earth / Earth Sciences
Dec 02, 2009 |
4.6 / 5 (10) |
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A new fossil species suggests that some land animals may have survived the end-Permian extinction by living in cooler climates in Antarctica. Researchers have identified a distant relative of mammals that apparently survived ...
New technology helps scientists understand ancient fossils
Other Sciences / Archaeology & Fossils
6 hours ago |
5 / 5 (1) |
1
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
19 hours ago |
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3
(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 ...
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EPA says greenhouse gases endanger human health
14 hours ago |
2.6 / 5 (5) |
11
(AP) -- The Environmental Protection Agency took a major step Monday toward regulating greenhouses gases, concluding that climate changing pollution threatens the public health and the environment.
The last best chance: UN climate conference opens
16 hours ago |
1.8 / 5 (5) |
3
(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 last best chance for a deal to protect ...
Secret behind the composition of the varnish on Stradivari violins revealed
Chemistry / Analytical Chemistry
Dec 04, 2009 |
4.7 / 5 (21) |
3
(PhysOrg.com) -- Antonio Stradivari is the most famous instrument maker of all time. He was especially famous for his violins, which he produced in Cremona from about 1665 until his death in 1737. In particular, ...
A greener way to get electricity from natural gas
Dec 03, 2009 |
3.5 / 5 (14) |
9
(PhysOrg.com) -- A new type of natural-gas electric power plant proposed by MIT researchers could provide electricity with zero carbon dioxide emissions to the atmosphere, at costs comparable to or less than ...
A Superbright Supernova That’s the First of Its Kind
Dec 02, 2009 |
4.7 / 5 (24) |
6
(PhysOrg.com) -- An extraordinarily bright, extraordinarily long-lasting supernova named SN 2007bi, snagged in a search by a robotic telescope, turns out to be the first example of the kind of stars that first ...
A light touch: Iron complexes as efficient catalysts for the light-driven extraction of hydrogen from water
Dec 02, 2009 |
5 / 5 (4) |
3
(PhysOrg.com) -- Hydrogen is a promising alternative energy carrier that can be efficiently converted into electrical energy in fuel cells. One hurdle to the introduction of sustainable hydrogen technology is the fact that ...
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