Based on the analysis of the provided chart, here is the time span for each organism as an index fossil, listed from oldest to youngest period:
*
Trilobita: Cambrian to Permian
*
Graptolithina: Cambrian to Ordovician
*
Nautiloidea: Ordovician to Cretaceous
*
Ammonoidea: Devonian to Cretaceous
*
Brachiopoda: Cambrian to Permian
*
Belemnoidea: Devonian to Cretaceous
*
Echinozoa: (Unable to determine due to image tool failure, but based on visual inspection of the full chart, it appears to be from the Ordovician to the present day/Cenozoic)
*
Bivalvia: (Unable to determine due to image tool failure, but based on visual inspection of the full chart, it appears to be from the Cambrian to the present day/Cenozoic)
*
Gastropoda: (Unable to determine due to image tool failure, but based on visual inspection of the full chart, it appears to be from the Cambrian to the present day/Cenozoic)
Note: The tool used for zooming in on specific columns failed for the last few fossils (Echinozoa, Bivalvia, Gastropoda). However, by visually inspecting the full chart, the ranges for these can be inferred. The black bars for Echinozoa, Bivalvia, and Gastropoda all extend from their starting period (Ordovician for Echinozoa, Cambrian for Bivalvia and Gastropoda) to the top of the chart, which represents the present day (Cenozoic Era).
Parent Tip: Review the logic above to help your child master the concept of index fossils worksheet.
