Mass extinction events have far-reaching effects on Earth’s ecosystems. Understanding their effects on biodiversity is critical for understanding how organisms adapt to changing environments and how these adaptations play a role in the evolution of new species and traits after the extinction. Studies on past ecosystems have shown that changes in diversity, body shape, abundance, and/or resource availability may determine the success of a certain group during these events.
During the Late Carboniferous geological period, just over 300 million years ago, a group of animals called amniotes evolved from amphibians. These animals differed from amphibians in that they laid a different kind of egg, called the amniotic or cleidoic egg. This special egg allowed amniotes to colonize the land as it could survive out of water, allowing these animals to expand into drier areas.
Going back in time to 252 million years ago, before the evolution of dinosaurs, birds, and mammals,the South African Karoo (Figure 1) looked very different from how it does today. Mississippi-sized rivers bordered by massive floodplains and lush vegetation traversed the land.