I like to use a meter stick and be very intentional with my spacing to model time as a scale. I also avoid using the ... a ruler to space years accordingly. An Index fossil is any animal or plant ...

The beginning and end of each chunk of time in the geologic time scale is determined by when some species appeared or disappeared from the fossil record. When many species went extinct around the same ...

The age of the fossil must be determined so it can be compared to other fossil species from the same time period ... relative ages of geological events preserved in the rock record.

The age of the fossil must be determined so it can be compared to other fossil species from the same time period ... relative ages of geological events preserved in the rock record.