| A | B |
|---|
| paleontologist | scientist who studies fossils |
| fossil record | information about past life, including the structure of organsism, what they ate, what are them, in what environment they lived, and the order in which they lived |
| extinct | term used to refer to a species that has died out |
| relative dating | method of determining the age of a fossil by comparing its placement with that of fossil in other layers of rock |
| 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 | techniqie in which scientist calculate the age of a sample based on the amount of remaining radioactive isotopes it contains |
| geologic time scale | scale used by paleontologist to represemt evolutionary time |
| era | one of the several subdivision of the time between the precambrian and the present |
| period | unit of time into which eras are subdivide |
| proteinoid microphere | tiny bubble, formed of large organic molecules, that has some characteristics of a cell |
| microsossil | microscopic fossils |
| endosymbiotic therory | theory that eukaryotic cells formed from a symbiosis among several diffrent prokaryotic organism |
