Section 5 Vetebrate History In Rocks Flashcards
What is a fossil ?
The hardened remains of other evidence of a living thing that existed a long time ago
Where can a fossil be imprinted
On a rock such as an animals footprint
What are other fossils?
Remains of bone, shells skeletons or other parts of living things
What type of rock are fossils mostly found in?
Sedimentary rock
What makes up sedimentary rock?
Hardened layers of sediments ( sediments contain particles of clay, sand, med or silt)
How do sediments build up into layers?
Wind blows into sand dunes or when muddy water stands still . Over a very very long time sediments can build up and harden into rock. When a plant or animal dies and is trapped in the sediments, it is sometimes preserved as a fossil
How do paleontologists infer how animals have changed over time?
By studying fossils
Fossils in which layers of rock are are younger?
Fossils in the higher level of rock are younger then the fossils in the lower levels
What other method do scientists use to determine the age of a fossil?
They use radioactive chemical elements. The radioactive elements decay over time . The more there is a decayed form of the element, the older the fossil is
Vertebrates are a subgroup of?
Chordates
Layers of clay, sand, and mud harden and become?
Sedimentary rock