Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
11 Cards in this Set
- Front
- Back
|
Mummification |
Preserves life form with some tissue or skin intact. Bones very fragile. Not true fossilization. |
|
|
External Molds |
Imprints of the organism embedded in rocks. |
|
|
Casts |
These are formed when external molds are filled with sediment. |
|
|
Internal molds |
These occur when sediment fills the shell of a deceased organism, such as a bivalve or a gastropod. These remain after the organism's remains decompose to show the internal features of the organism |
|
|
Petrification/Petrifaction/Silicification |
These occur when minerals slowly replace the various organic tissues of an organism with minerals. The most common mineral to cause petrification is silicon, but other minerals will also work. |
|
|
Carbonization/Coalification |
These occur when over time all parts of the original organism except the carbon are removed from the fossil over time. The remaining carbon is the same carbon that the organism was made of. |
|
|
Recrystallization |
These occur when original minerals in the fossil over time revert into more stable minerals, such as an apatite shell recrystallizing into the more thermodynamically stable calcite. |
|
|
Replacement |
This occurs when the hard parts of the organism are replaced with minerals over time. |
|
|
Trace fossils |
Trace fossils are fossils that aren't exactly part of the organism. These include footprints, burrows, eggshells, and my personal favorite, coprolite (or fossilized excrement).They give insight into an organism's behavior. |
|
|
Actual remains |
These are much rarer than other fossil types. These are still intact parts of the organism. Actual remains can be seen preserved in ice, tar, or amber. A good example is mammoth hair. It is often frozen and still preserved. |
|
|
Tar |
When organisms become trapped in tar, due to the oxygen deprived environment, it allows for the rapid burial of body parts which are well preserved. A good example is the La Brea tar pits in Los Angeles. |
