Late Devonian

Definition

The Late Devonian is a specific time interval in the Devonian period, occurring approximately 382 to 359 million years ago, characterized by significant geological, climatic, and biological changes. This period witnessed the diversification of fish, the first appearance of amphibians, and major changes in marine ecosystems, which are pivotal for understanding the development of life on Earth during the Paleozoic Era.

5 Must Know Facts For Your Next Test

1. The Late Devonian is known for two major extinction events, which significantly affected marine life and led to the loss of many coral reefs and fish species.
2. During this time, early tetrapods began to evolve from lobe-finned fish, marking an important transition from aquatic to terrestrial life.
3. The climate during the Late Devonian was generally warm and humid, which contributed to lush vegetation and widespread forests that would later play a role in oxygen production.
4. Major reef-building organisms during this period included stromatoporoids and corals, which played essential roles in marine ecosystems.
5. The Late Devonian is often marked by the development of extensive continental deposits that indicate significant shifts in sedimentation patterns due to tectonic activity.

Review Questions

• What were some key biological developments that occurred during the Late Devonian, and how did they influence the evolution of life on Earth?
  • During the Late Devonian, one of the most significant biological developments was the evolution of early tetrapods from lobe-finned fish. This transition marked an essential step in the move from aquatic to terrestrial life, setting the stage for vertebrate diversification on land. Additionally, the period saw a remarkable diversification of fish species and marine life, which contributed to complex ecosystems that played a crucial role in shaping biological diversity.
• Analyze the impact of extinction events during the Late Devonian on marine ecosystems and biodiversity.
  • The extinction events of the Late Devonian had a profound impact on marine ecosystems and biodiversity. These events resulted in the loss of approximately 70% of all marine species, including many coral reef builders and various fish taxa. The decline in diversity altered community structures within oceans, leading to long-term effects on marine life that shaped future evolutionary paths. The collapse of these ecosystems highlighted vulnerabilities within marine environments during times of environmental change.
• Evaluate how the climatic conditions during the Late Devonian influenced both terrestrial and marine environments.
  • The climatic conditions during the Late Devonian were generally warm and humid, fostering extensive forests and diverse terrestrial vegetation. This abundance of plant life played a crucial role in increasing atmospheric oxygen levels and contributing to soil formation. In marine environments, these climatic conditions supported rich biodiversity with flourishing reef systems. However, as climate fluctuated towards cooler periods and faced increased sedimentation due to tectonic activity, both terrestrial and marine ecosystems experienced stress that would culminate in extinction events.

Related terms

Devonian Period: A geological period within the Paleozoic Era, spanning from about 419 to 359 million years ago, known as the 'Age of Fishes' due to the dominance of fish in marine environments.

Frasnian: The second stage of the Late Devonian, marked by a peak in diversity among marine organisms and significant geological changes.

Extinction Events: Major events in Earth's history where a significant percentage of species went extinct; during the Late Devonian, one of the most notable events led to a severe loss of marine biodiversity.