| A | B |
|---|
| fossil | !0,000 year-old preserved evidence (structure or trace) of life |
| fossil record | all of the structural and trace fossils we have |
| extinct | an entire species, family, or other group having no remaining living members |
| relative dating | the science of determining age and order of past life/events based upon their positions in relation to one another in rock layers |
| index fossil | preserved evidence of an organism that lived for a short time in a wide geographical range |
| absolute dating | the science of measuring specific physical aspects of a sample to calculate its age |
| radioactive dating | a form of absolute dating that examines levels of decay in radioactive atoms contained within a sample to determine the age of the sample |
| half life | the amount of time tht it takes for a particular radioactive atom to decay by 50% |
| structural fossil | a preserved body part |
| trace fossil | preserved evidence of an organism that is not the organism itself |
