End-Triassic

Definition

The End-Triassic refers to a major geological event that occurred approximately 201 million years ago, marking the boundary between the Triassic and Jurassic periods. This event is significant due to the mass extinction it caused, leading to the loss of many marine and terrestrial species and dramatically reshaping ecological communities. The end-Triassic event illustrates how catastrophic changes can disrupt ecosystems and pave the way for new groups of organisms to dominate in the aftermath.

5 Must Know Facts For Your Next Test

1. The end-Triassic mass extinction is estimated to have wiped out around 76% of all species on Earth, significantly altering biodiversity.
2. One major cause believed to contribute to this extinction was extensive volcanic activity, which released large amounts of CO2 and other gases, leading to climate changes.
3. The extinction event allowed dinosaurs to become the dominant terrestrial vertebrates during the Jurassic period following the End-Triassic.
4. Marine life was heavily affected, with many groups such as ammonites and certain reef builders disappearing from fossil records.
5. The recovery from the end-Triassic event took millions of years, allowing ecosystems to gradually stabilize and evolve into their new forms.

Review Questions

• How did the end-Triassic extinction impact the evolution of subsequent ecological communities?
  • The end-Triassic extinction led to significant shifts in ecological communities by eliminating many dominant species, particularly marine reptiles and certain types of plants. This created open niches that allowed for the diversification and evolution of new groups, particularly dinosaurs. With reduced competition and predation pressure, these new organisms could thrive and become more diverse in subsequent periods, illustrating how mass extinctions can reshape ecosystems dramatically.
• Evaluate the main causes of the end-Triassic mass extinction and their implications for future ecological stability.
  • The main causes of the end-Triassic mass extinction are thought to include extensive volcanic eruptions leading to climatic shifts and ocean acidification. These environmental stresses resulted in habitat loss and changes in species distributions. The implications for future ecological stability were profound; this event highlighted how quickly ecosystems could be destabilized by environmental changes, emphasizing the delicate balance within ecological communities and the importance of biodiversity for resilience.
• Synthesize information on how recovery after the end-Triassic extinction informs our understanding of resilience in ecological communities over geological time scales.
  • Recovery after the end-Triassic extinction offers valuable insights into ecological resilience, showcasing how devastated ecosystems can eventually rebound. Following this mass extinction, there was a gradual re-establishment of biodiversity, with new species evolving to fill vacant ecological roles. This process illustrates a pattern where ecosystems can adapt to change over time despite initial losses. Understanding these recovery dynamics helps frame contemporary discussions about resilience in modern ecosystems facing current environmental pressures.

Related terms

Mass Extinction: A widespread and rapid decrease in the biodiversity on Earth, characterized by the extinction of a significant percentage of all species.

Triassic Period: The first period of the Mesozoic Era, spanning from about 252 to 201 million years ago, marked by the emergence of dinosaurs and mammals.

Jurassic Period: The second period of the Mesozoic Era, occurring after the Triassic, known for a diverse range of dinosaurs and the first birds appearing.