Late Devonian

Definition

The Late Devonian is a geologic period that occurred roughly 382 to 359 million years ago, marking the final phase of the Devonian period. This era is significant for its remarkable biodiversity, especially in marine life, and is well-known for the mass extinction events that profoundly impacted ecosystems and species diversity.

5 Must Know Facts For Your Next Test

1. The Late Devonian is characterized by two major mass extinction events, one occurring at the Frasnian-Famennian boundary and another earlier in the Late Devonian.
2. These extinction events led to significant declines in coral reefs and many fish species, impacting marine ecosystems extensively.
3. During the Late Devonian, significant evolutionary changes occurred with the rise of early terrestrial plants, which helped shape land ecosystems.
4. The climate during the Late Devonian was generally warm and humid, contributing to lush vegetation on land and diverse life in oceans.
5. The Late Devonian marked an important transition for vertebrates, as early amphibians began to emerge from fish ancestors during this time.

Review Questions

• How did the Late Devonian period contribute to changes in biodiversity and marine ecosystems?
  • The Late Devonian period saw significant changes in biodiversity largely due to two mass extinction events that caused dramatic losses in marine species. These extinctions particularly affected coral reefs and various fish groups, altering food webs and ecosystem dynamics. The decrease in biodiversity during this time had lasting effects on the structure and composition of marine communities, demonstrating how extinction events can reshape ecological landscapes.
• Evaluate the impact of the Frasnian-Famennian extinction on both marine life and terrestrial ecosystems during the Late Devonian.
  • The Frasnian-Famennian extinction had a profound impact on marine life, leading to the decline or disappearance of numerous species including reef builders like corals and various fish types. This loss altered marine ecosystems significantly, reducing habitat complexity and available resources. On land, while early terrestrial plants thrived, the reduction in marine biodiversity impacted nutrient cycles and ecological interactions, highlighting the interconnectedness of terrestrial and marine environments.
• Analyze how the climatic conditions of the Late Devonian influenced evolutionary trends among terrestrial and aquatic organisms.
  • During the Late Devonian, the warm and humid climate facilitated lush vegetation growth on land, leading to increased habitat diversity for terrestrial organisms. This environment provided opportunities for early amphibians to evolve from fish ancestors as they began to exploit terrestrial habitats. Meanwhile, aquatic organisms were influenced by changing water temperatures and reduced oxygen levels due to extinction events, which pushed them toward adaptation or survival in increasingly challenging conditions. The interplay between climate and evolution during this time underscores how external factors can drive biological innovation and diversity.

Related terms

Devonian Period: A major division of the Paleozoic Era, known as the 'Age of Fishes,' where significant evolutionary advancements occurred in both marine and terrestrial environments.

Mass Extinction: A widespread and rapid decrease in biodiversity on Earth, during which a significant number of species become extinct in a relatively short period of geological time.

Frasnian-Famennian Extinction: The most notable extinction event at the end of the Late Devonian, characterized by a dramatic loss of marine species, including many reef-building organisms.