Name: _________________________________________ Chapter F Lesson 4: Looking at Fossils QUIZ date: _______________________ Vocabulary: 1. Fossil – the trace or remains of an organism that lived long ago, most commonly preserved in sedimentary rock 2. Trace Fossil – a fossilized mark that is formed in soft sediment by the movement of an animal 3. Mold – a mark or cavity made in a sedimentary surface by a shell or other body 4. Cast – a type of fossil that forms when sediments fill in the cavity left by a decomposed organism 5. Index Fossil – a fossil that is found in the rock layers of only one geologic age and that is used to establish the age of the rock layers Things to Know: 1. Amber is hardened tree sap and petrified wood is an example of mineral replacement. 2. Preserved footprints or a mark left by a dinosaur’s tail would be examples of trace fossils. Animal tracks can tell how big the animal was that left the track. 3. Freezing temperatures will slow down an organism’s decay. 4. Marine fossils discovered on a mountaintop tell the scientists that the rock was once below the ocean’s surface. 5. Scientists can learn how life has changed and the age of certain layers of rock by studying fossils and the relationship between them. 6. Most fossils are preserved in sedimentary rock. 7. The fossil record is incomplete because most organisms never became fossils. 8. Shells and bones are more commonly preserved because of their hardness and the fact that it takes a longer time for them to break down than soft tissue. 9. Mineral replacement is a process where minerals replace tissue.