Term | Definition |
fossil | the trace or remains of an organisms that lived long ago, most commonly preserved in sedimentary rock |
petrified fossil | happens when an organism's tissues are replaced by minerals |
mold | forms when hard parts of an organism are buried in sediment, such as sand, silt, or clay |
casts | forms as the result of a mold. minerals and sediment that are left in the mold make a cast. a cast is the opposite of a mold |
carbon films | thin layer of carbon left behind can show an organism's delicate parts, like leaves on a plant |
trace fossil | is a fossilized structure that formed in sedimentary rock by animal activity on or in soft sediment |
preserved remains | remains of organisms are preserved in substances such as tar, amber, or ice |
paleontologist | scientists who study fossils |
fossil record | all the information that paleontologists have gathered about past life |
evolution | gradual change in living things over long periods of time |
extinct | no longer exists and will never again live on Earth |
uniformitarianism | geological process that happened in the past are explained by current geological processes (volcanoes) |
unconformity | is a break in the geologic record that is made when rock layers are eroded or when sediment is not deposited for a long period of time |
Rock cycle | Series of process In which rocks form, changes from one type to another, is broken down or melted, and forms again by geologic processes |
Compaction | Is a process where layers build up as pressure increases the bottom layers stick together to form solid rock |
Sedimentary Rocks | Made by compaction and cementation, forms when sediments are compacted together by pressure and are cemented together when minerals form from solutions |
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