Late Devonian

Definition

The Late Devonian is the final stage of the Devonian period, spanning from approximately 383 to 359 million years ago. This time is marked by significant geological, climatic, and biological changes, including the diversification of fish, the emergence of early amphibians, and substantial shifts in marine environments, leading to one of the largest mass extinctions in Earth's history.

5 Must Know Facts For Your Next Test

1. The Late Devonian was characterized by the appearance of early amphibians, marking a critical transition from water to land vertebrates.
2. Marine life flourished during this period, especially with diverse fish species like placoderms and lobe-finned fishes, which are crucial for understanding vertebrate evolution.
3. One of the most notable events of the Late Devonian was the Late Devonian extinction event, which caused massive loss of marine species, including many reef-building organisms.
4. Changes in sea level and climate during the Late Devonian had a profound impact on both terrestrial and marine ecosystems.
5. The Late Devonian also saw extensive development of terrestrial plant life, contributing to changes in soil composition and atmosphere due to increased photosynthesis.

Review Questions

• How did the biological developments during the Late Devonian contribute to evolutionary transitions in vertebrates?
  • During the Late Devonian, significant biological developments occurred with the emergence of early amphibians from lobe-finned fish. This transition was crucial as it marked a movement from aquatic environments to terrestrial habitats. The diversification of these early amphibians helped establish a lineage that would lead to modern amphibians and eventually other land vertebrates, showcasing the interconnectedness of evolutionary pathways.
• Discuss the factors that led to the Late Devonian extinction event and its impact on marine biodiversity.
  • The Late Devonian extinction event was influenced by various factors such as climate change, anoxic events in oceans, and fluctuations in sea levels. These conditions created hostile environments for many marine species, leading to significant losses in biodiversity. The extinction particularly affected reef ecosystems and several fish groups, reshaping marine communities and paving the way for new evolutionary paths in subsequent periods.
• Evaluate the long-term consequences of ecological changes during the Late Devonian on subsequent geological periods.
  • The ecological changes during the Late Devonian had profound long-term consequences that shaped subsequent geological periods. The loss of marine biodiversity set a precedent for ecological recovery and adaptation in later periods. Additionally, the rise of terrestrial plants and early amphibians during this time laid foundational elements for land ecosystems that would flourish in future eras. As new ecological niches developed post-extinction, they facilitated evolutionary experimentation that influenced life forms throughout Earth's history.

Related terms

Mass Extinction: A widespread and rapid decrease in biodiversity on Earth, often characterized by the loss of a significant percentage of species in a relatively short geological timeframe.

Devonian Period: A major division of the geologic time scale that lasted from about 419 to 359 million years ago, known as the 'Age of Fishes' due to the diversity and dominance of fish species during this time.

Frasnian: The second-to-last stage of the Devonian period, occurring before the Late Devonian, recognized for significant biological and geological developments that set the stage for later changes.