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 record
Ancient muscle tissue extracted from 18 million year old fossil
Other Sciences / Archaeology & Fossils
Nov 05, 2009 |
4.7 / 5 (10) |
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(PhysOrg.com) -- Scientists have extracted organically preserved muscle tissue from an 18 million years old salamander fossil. The discovery by researchers from University College Dublin, the UK and Spain, ...
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Tesla Roadster Goes 313 Miles on a Single Charge
Nov 09, 2009 |
4.4 / 5 (14) |
2
(PhysOrg.com) -- Tesla is becoming synonymous with high performance electric cars. Indeed, the Tesla car company has been making efforts to create a brand of sports car that runs on electricity, and does so ...
The last European hadrosaurs lived in the Iberian Peninsula
Other Sciences / Archaeology & Fossils
Nov 05, 2009 |
4.5 / 5 (2) |
0
Spanish researchers have studied the fossil record of hadrosaurs, the so-called 'duck-billed' dinosaurs, in the Iberian Peninsula for the purpose of determining that they were the last of their kind to inhabit ...
INL develops safer, more efficient nuclear fuel for next-gen reactors
Nov 30, 2009 |
4.5 / 5 (15) |
6
As the nation ponders its energy choices, Americans keep asking themselves: how can the country make better use of its resources and emit fewer greenhouse gases without hurting U.S. industries? A research ...
Oceans' uptake of manmade carbon may be slowing
Space & Earth / Earth Sciences
Nov 18, 2009 |
3.8 / 5 (23) |
10
The oceans play a key role in regulating climate, absorbing more than a quarter of the carbon dioxide that humans put into the air. Now, the first year-by-year accounting of this mechanism during the industrial ...
Climate experts debate strategies for reducing atmospheric carbon and future warming
Nov 25, 2009 |
2.5 / 5 (14) |
23
(PhysOrg.com) -- Reducing carbon dioxide to safe levels may require extracting carbon from the air, says Cornell climate researcher.
Advanced nuclear fuel sets global performance record
Nov 17, 2009 |
4.5 / 5 (21) |
1
(PhysOrg.com) -- Idaho National Laboratory scientists have set a new world record with next-generation particle fuel for use in high temperature gas reactors (HTGRs).
After mastodons and mammoths, a transformed landscape
Space & Earth / Earth Sciences
Nov 19, 2009 |
4.6 / 5 (12) |
1
(PhysOrg.com) -- Roughly 15,000 years ago, at the end of the last ice age, North America's vast assemblage of large animals -- including such iconic creatures as mammoths, mastodons, camels, horses, ground ...
Paleontologists find extinction rates higher in open-ocean settings during mass extinctions
Space & Earth / Earth Sciences
Nov 19, 2009 |
5 / 5 (1) |
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Arnie Miller, University of Cincinnati professor of paleontology in the McMicken College of Arts & Sciences, and co-author Michael Foote of the University of Chicago publish their research in the Nov. 20 issue ...
Male sabertoothed cats were pussycats compared to macho lions
Nov 05, 2009 |
4.2 / 5 (6) |
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Despite their fearsome fangs, male sabertoothed cats may have been less aggressive than many of their feline cousins, says a new study of male-female size differences in extinct big cats.
Warm-blooded dinosaurs worked up a sweat
Nov 11, 2009 |
5 / 5 (5) |
1
(PhysOrg.com) -- Were dinosaurs endothermic (warm-blooded) like present-day mammals and birds or ectothermic (cold-blooded) like present-day lizards? The implications of this simple-sounding question go beyond ...
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