WJEC Geology GL5 Evolution & British Geology — Papers & Mark Schemes

Study the five major mass extinction events (end-Ordovician, late Devonian, end-Permian, end-Triassic, end-Cretaceous) and their proposed causes. For each, know the geological evidence (e.g., iridium anomaly at the K-Pg boundary, flood basalt provinces), the groups affected, and the evolutionary consequences. Examiners reward candidates who can explain how extinction events create ecological opportunities for surviving groups. British stratigraphy questions require knowledge of the key formations that define each Period in Britain. Know where the type sections are located: Cambrian in Wales, Silurian and Ordovician in the Welsh Borderlands, Carboniferous Limestone in the Mendips and Pennines, Jurassic along the Dorset coast, and Chalk across southern England. Link each to its depositional environment and tectonic setting. Evolutionary transition questions test your understanding of the anatomical and physiological changes involved. For the fish-to-tetrapod transition, for example, know the key intermediate fossils (Tiktaalik, Acanthostega) and the structural adaptations (weight-bearing limbs, lungs, changes to skull mobility) that enabled life on land.