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Fossils are often formed by pseudomorphic replacement of the remains by mineral matter. Examples include petrified wood and pyritized gastropod shells. In biology, a pseudomorph is a cloud of mucus-rich ink released by many species of cephalopod. The name refers to the similarity in appearance between the cephalopod that released it and the ...
Tree remains that have undergone petrifaction, as seen in Petrified Forest National Park. In geology, petrifaction or petrification (from Ancient Greek πέτρα (pétra) 'rock, stone') is the process by which organic material becomes a fossil through the replacement of the original material and the filling of the original pore spaces with minerals.
Permineralized fossils preserve the original cell structure, which can help scientists study an organism at the cellular level. These three-dimensional fossils create permanent molds of internal structures. The mineralization process helps prevent tissue compaction, distorting organs' actual size.
Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood and DNA remnants. The totality of fossils is known as the fossil record. Though the fossil record is incomplete, numerous studies have demonstrated that there is enough information available to give a good ...
Evolutionary developmental biology, commonly abbreviated to "Evo Devo", also helps paleontologists to produce "family trees", and understand fossils. [68] For example, the embryological development of some modern brachiopods suggests that brachiopods may be descendants of the halkieriids, which became extinct in the Cambrian period. [69]
Together, the fossil pieces tell the story of a creature that defied all expectations based on the evolutionary paths of better-known animals from the time, which mostly lived closer to the equator.
The replacement of fossils with chert, for example, is often fabric-preserving, while the replacement of aragonite and calcite with dolomite is fabric-destructive. On a side note, this particular process (the replacement of aragonite and calcite with dolomite) is the most common form of recrystallization by replacement.
In some silicified sedimentary rocks, fossils of diatoms are unearthed. This suggests that diatoms frustules were sources of silica for silicification. [ 13 ] Some examples are silicified limestones of Miocene Astoria Formation in Washington, silicified ignimbrite in El Tatio Geyser Field in Chile, and Tertiary siliceous sedimentary rocks in ...