Preserved remains or traces of living things. Tell geologists about the life-forms and environments of Earth's past. Provide geologist with clues about events and relative age of rock layers. Most do not look like modern life forms bacause most of the organisms that turned into fossils have been extinct for a long, long time.
parts of the original organism that have been preserved. Hard parts, like shells, teeth, and bones commonly become fossil because they take much longer to decay than fleshy and soft body parts.
minerals brought in by groundwater replace the original compounds of the body part
not just parts of the body, but the entire organism. Examples: insects in amber, frozen mammoths in the tundra, La Brea tar pits of LA preserved whole skeletons.
not the actual remains but evidence of the organism that produced them. Examples: Impressions of shells, footprints, animal droppings
fossils of New York
coral and warm-water marine organisms, indicating that warm (tropical) seas once covered NY. Recent wooly mammoths and mastodonts, revealing cold, icy climate of ice age
matching rock layers (strata) in different locations to see if they formed at the same time and under the same conditions. When correlating, look for color, texture, and composition of the rock. It is helpful to use overall sequence of the rock (Ex: 1st shale, then limestone, then sandstone. Find other rock outcrops with the same order) Think of matching the overlapping sandwich layers in class.
remains of organisms as a species that existed for (A) a relatively brief period of time (B)found over a widespread geographic distribution (locations) Things to look for: in many outcrops, but only one layer (not top to bottom)
event that happened quickly and was widespread. Examples: volcanic eruptions, meteorite impacts