Question

. Explain how paleontologists use trilobite fossils as index fossils for various geologic time periods.

Answer 1

Trilobites were rapidly evolving and widespread marine organisms that spanned a number of geologic time periods. Certain types of trilobites only appeared in specific segments of geologic time; therefore, when one of these trilobites is found, you can be certain that the rock layer it is found in is of a certain geologic age.