End-Triassic

Definition

The end-Triassic refers to a significant geologic boundary that marks the transition from the Triassic Period to the Jurassic Period, approximately 201 million years ago. This boundary is characterized by a major mass extinction event that led to the loss of many species, particularly marine reptiles, and significant changes in terrestrial ecosystems. Understanding this period helps highlight critical shifts in Earth's biodiversity and climate that influenced subsequent geological time.

5 Must Know Facts For Your Next Test

1. The end-Triassic mass extinction event resulted in the extinction of nearly 76% of all species on Earth, drastically altering ecosystems.
2. This extinction event is believed to be linked to massive volcanic eruptions in what is now the Central Atlantic Magmatic Province, contributing to climate change and ocean acidification.
3. The end-Triassic marks a pivotal point in the history of dinosaurs, as it set the stage for their dominance during the Jurassic period following the extinction of many competitors.
4. Fossil evidence shows that after the end-Triassic extinction, ecosystems quickly rebounded and diversified, paving the way for new groups of organisms.
5. The changes at the end-Triassic had long-lasting effects on global biodiversity, influencing evolutionary trajectories that shaped future life forms.

Review Questions

• Discuss how the end-Triassic extinction impacted both marine and terrestrial ecosystems.
  • The end-Triassic extinction had profound effects on both marine and terrestrial ecosystems. In marine environments, it led to the loss of dominant groups such as ammonites and certain marine reptiles, allowing other species to fill these ecological roles over time. On land, many archosaurs faced extinction, clearing the way for dinosaurs to evolve and dominate during the Jurassic. This reshaping of life forms initiated significant ecological changes that would define Mesozoic ecosystems.
• Evaluate the potential causes of the end-Triassic mass extinction and their significance for understanding climate change.
  • The end-Triassic mass extinction is thought to have been caused primarily by massive volcanic eruptions that released large amounts of carbon dioxide into the atmosphere. This led to global warming, altered precipitation patterns, and ocean acidification, creating harsh conditions for many species. Understanding these causes highlights how natural geological events can trigger rapid climate changes with far-reaching impacts on biodiversity, a crucial lesson given current anthropogenic climate change.
• Analyze how the aftermath of the end-Triassic extinction influenced evolutionary paths leading into the Jurassic Period.
  • After the end-Triassic extinction, ecosystems underwent rapid recovery and diversification, which played a critical role in shaping evolutionary paths. The extinction of many established species allowed for new groups to emerge and flourish, particularly dinosaurs and mammals. This evolutionary transition set up a dynamic environment where traits favored survival could rapidly evolve, leading to significant innovations in anatomy and behavior among surviving taxa. This period is essential for understanding how life adapts after mass extinction events.

Related terms

Mass Extinction: A rapid and widespread 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, spanning from approximately 252 to 201 million years ago, known for the emergence of dinosaurs and the diversification of reptiles.

Jurassic Period: The second period of the Mesozoic Era, following the Triassic, lasting from about 201 to 145 million years ago, known for the dominance of dinosaurs and significant advancements in plant life.