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17 terms

gen sci #7

STUDY
PLAY
types of fossils
1-molds and casts; 2-petrified remains; 3-carbonate residues; 4-impressions; 5-creatures trapped in ice; 6-creatures trapped in amber
mold
an imprint formed like the object would make if pressed into clay (like footprints)
cast
solid rock that has the same shape and surface details as the original object
petrifaction *
the conversion of organic material into stone
petrified remains
original parts either replaced bit-by-bit or preserved by being exposed to water that contains a lot of minerals (shows details within as well as on the surface)
carbonate residue
a fossil formed by the thin, filmy residue left when the liquids and gases of a creature's remains are forced out of the creature by great pressure after it has been buried in sediment
impression
the fossil resulting after the thin, filmy residue of the carbonate residue is gone and just the impression of the film remains
resin *
a sticky, liquid substance that usually hardens when exposed to air
first general feature of the fossil record
Fossils are usually found in sedimentary rock. Since most sedimentary rock is laid down by water, it follows that most fossils were laid down by water as well.
second general feature of the fossil record
The vast majority of fossils are of clams and other hard-shelled creatures. Most remaining fossils are of either water-dwelling creatures or insects. Only a tiny, tiny fraction of the fossils we find are of plants, reptiles, birds, and mammals.
third general feature of the fossil record
Many of the fossils we find are of plants and animals which are still alive today. Some of the fossils we find are of plants and animals which are now extinct.
fourth general feature of the fossil record
The fossils found in one layer of stratified rock can be considerably different than the fossils found in another layer of the same stratified rock.
extinct *
a term applied to a species of plant or animal that was once living but now is not
uniformitarianism
the view that most of earth's geological features are the result of slow, gradual processes that have been at work for millions or even billions of years
catastrophism
the view that most of earth's geological features are the result of large-scale catastrophes such as floods, volcanic eruptions, etc.
trilobrite
a creature that lived in the water and was covered in a hard outer covering
placoderm
a kind of fish that is now extinct. It was covered hard plates instead of scales