1. The Fossil Record

2. Terms Paleontologist: scientist who studies fossils
Fossil record: information about past life, including the structure of organisms, what they ate, what ate them, in what environment they lived, and the order in which they lived
Extinct: the whole species has died out
Relative dating: determine the age of the fossil by looking at which layer of rock the fossil was found

3. More terms
Index fossil: distinctive fossil used to compare the relative ages of fossils
Half-life: length of time required for half of the radioactive atoms in a sample to decay
Radioactive dating: using half-lives to determine the age of a sample of rock or a fossil
Geologic time scale: scale used by paleontologists to represent the history of the Earth

4. More terms again
Era: one of the subdivisions of the time between Precambrian times and now
Paleozoic—544 to 245 million years ago
Mesozoic—245 to 65 million years ago
Cenozoic—65 million yeas ago to right NOW
AND NOW!
Period: unit of time into which eras are subdivided