If a large decrease in temperature occurs in a short period of time the effects would be extreme for ectothermic tetrapods, that is, reptiles and amphibians (J.D. Archibald, 1996). Ectothermic organisms use environmental energy (i.e. heat) to regulate their body temperature.
Some ectothermic tetrapods could have escaped the temperature change by taking shelter in caves, cracks, between rocks etc. Some large ectotherms like dinosaurs were too large to take shelter and were therefore subjected to the cold conditions.
Endotherms are organisms that can generate their own body heat through metabolic processes. These organisms would have been less affected by the temperature changes.