End-Triassic extinction

Definition

The end-Triassic extinction was a major event in Earth's history that occurred around 201 million years ago, marking the boundary between the Triassic and Jurassic periods. It resulted in the loss of approximately 76% of all species on Earth, significantly impacting both marine and terrestrial life and paving the way for the rise of dinosaurs during the Jurassic period.

5 Must Know Facts For Your Next Test

1. The end-Triassic extinction was one of the five major mass extinction events in Earth's history, alongside others such as the Permian-Triassic extinction and Cretaceous-Paleogene extinction.
2. The causes of the end-Triassic extinction are believed to include volcanic activity, climate change, and ocean acidification, which disrupted ecosystems both on land and in the ocean.
3. Fossil evidence shows that many groups were heavily affected by this extinction event, including large amphibians and certain marine reptiles, leading to significant shifts in biodiversity.
4. After the end-Triassic extinction, dinosaurs became the dominant terrestrial vertebrates for the remainder of the Mesozoic Era, influencing evolutionary trajectories for millions of years.
5. The recovery from the end-Triassic extinction took millions of years, but it ultimately set the stage for dramatic changes in ecosystems, allowing new species to emerge and thrive.

Review Questions

• What were some of the primary causes believed to contribute to the end-Triassic extinction, and how did they impact biodiversity?
  • The end-Triassic extinction is thought to have been caused by several factors, including extensive volcanic activity that released large amounts of CO2 into the atmosphere, leading to climate change and ocean acidification. These changes disrupted ecosystems by altering habitats and food sources. As a result, a significant portion of biodiversity was lost, with many species unable to adapt to the rapidly changing environment.
• Discuss how the end-Triassic extinction influenced the evolutionary trajectory of dinosaurs during the Jurassic period.
  • Following the end-Triassic extinction, dinosaurs emerged as the dominant terrestrial vertebrates. The reduction in competition from other reptiles allowed dinosaurs to diversify and occupy various ecological niches. This adaptive radiation resulted in numerous dinosaur lineages flourishing during the Jurassic period, leading to their eventual dominance in ecosystems for millions of years thereafter.
• Evaluate the long-term effects of the end-Triassic extinction on marine ecosystems and terrestrial life as a whole.
  • The end-Triassic extinction had profound long-term effects on both marine ecosystems and terrestrial life. In marine environments, a significant loss of species led to changes in community structure and function. Terrestrially, it allowed dinosaurs to become dominant while also facilitating the evolution of mammals and other groups in their absence. This event reshaped ecological dynamics and biodiversity patterns that would influence future evolutionary developments for millions of years.

Related terms

mass extinction: A widespread and rapid decrease in the biodiversity on Earth, typically characterized by the extinction of a large number of species in a relatively short period.

Triassic period: The first period of the Mesozoic Era, lasting from about 252 to 201 million years ago, characterized by the emergence of dinosaurs, mammals, and various reptiles.

Jurassic period: The second period of the Mesozoic Era, spanning from about 201 to 145 million years ago, known for the dominance of dinosaurs and the diversification of flora and fauna.