text: Vital effects are relevant to study because of their influence on paleoclimatic interpretations. Scientists study the isotopic composition of marine organisms’ shells that have been preserved in marine sediment in order to reconstruct past environmental conditions. The earliest example of this work is using oxygen isotopes from the calcium carbonate (CaCO) in belemnites to reconstruct paleotemperatures. It is important to understand vital effects because they affect how paleoclimatic data are interpreted, which influences how scientists predict future impacts of climate change.