a shark would not be a good index fossil
Geography · Middle School · Tue Nov 03 2020
Answered on
That's correct. Index fossils are typically used to date and correlate the age of rock layers.
Sharks have a wide distribution, and their evolutionary history spans a long time without significant changes in their basic body structure.
For an organism to be a good index fossil, it should be geographically widespread, but its existence should be limited to a relatively short geological time span.
This allows scientists to use its presence to date the rocks in whibch iut is found more precisely.