What caused the Ordovician-Silurian extinction event?

The Ordovician-Silurian extinction event, occurring around 443 million years ago, is largely attributed to changes in sea levels. During this period, significant tectonic activity caused alterations in the distribution of continents and ocean basins, leading to fluctuations in sea levels. These changes resulted in the loss of habitats, particularly for marine species that thrived in shallow water environments.

As sea levels dropped, many coastal and shallow-water ecosystems were disrupted, leading to a decline in biodiversity. The organisms that were unable to adapt to the changing conditions or migrate to different habitats faced extinction. This event is a prime example of how geological and environmental changes can dramatically affect ecosystems and lead to mass extinctions in Earth's history.

While other potential factors like climate change and volcanic activity did play roles in shaping these ancient environments, the primary trigger for the Ordovician-Silurian extinction is well-supported by evidence linking it to the rise and fall of sea levels. Such fluctuations fundamentally altered the ecological landscape of the time, making it a crucial factor in this extinction event.