A Timeline of the Five Major Mass Extinctions in Earth’s History

Earth’s history is marked by several dramatic shifts in biodiversity, with five major mass extinctions reshaping life on our planet. These events drastically reduced the number of species and paved the way for new forms of life to emerge. Understanding these mass extinctions helps us appreciate the resilience and adaptability of life over millions of years.

The Ordovician-Silurian Extinction (Approximately 444 million years ago)

The first major mass extinction occurred during the late Ordovician period. Triggered by a short, intense ice age that lowered sea levels, it resulted in the loss of an estimated 85% of marine species. This event primarily affected marine invertebrates such as brachiopods and trilobites, which were abundant at that time.

The Late Devonian Extinction (About 375 million years ago)

This prolonged series of extinction pulses mainly impacted marine life over several million years during the Devonian period. Approximately 75% of species, including many fish and reef-building organisms like corals, disappeared. The causes are believed to include widespread anoxia (lack of oxygen) in oceans and climate changes.

The Permian-Triassic Extinction (Around 252 million years ago)

Known as “The Great Dying,” this was Earth’s most severe extinction event, wiping out around 96% of marine species and 70% of terrestrial vertebrate species. Possible causes include massive volcanic eruptions leading to global warming, ocean acidification, and loss of habitat stability.

The Triassic-Jurassic Extinction (Approximately 201 million years ago)

This extinction event cleared the path for dinosaurs to dominate Earth by eliminating about 80% of species including many amphibians and large reptiles. Its causes are linked to volcanic activity associated with the breakup of the supercontinent Pangaea causing climate fluctuations.

The Cretaceous-Paleogene Extinction (About 66 million years ago)

Famous for ending the reign of non-avian dinosaurs, this extinction saw nearly 75%of all species vanish from Earth. A massive asteroid impact near present-day Mexico combined with volcanic activity led to rapid environmental changes affecting both land and sea ecosystems.

These five major mass extinctions highlight Earth’s dynamic biological history shaped by natural catastrophes and environmental shifts. Studying them gives us valuable perspective on present-day biodiversity challenges and underscores our role in protecting life on Earth.

This text was generated using a large language model, and select text has been reviewed and moderated for purposes such as readability.