Late Devonian Extinction

Definition

The Late Devonian Extinction was a major extinction event that occurred approximately 375 to 360 million years ago, marking the end of the Devonian Period. This extinction led to significant losses in marine life, particularly among reef-building organisms and fish species, shaping the evolutionary trajectory of the Earth's biodiversity.

5 Must Know Facts For Your Next Test

1. The Late Devonian Extinction is believed to have occurred in multiple phases, with evidence suggesting that it spanned several million years rather than being a single event.
2. One of the most affected groups during this extinction was the placoderm fish, which saw a dramatic decline in species diversity.
3. Coral reefs suffered greatly during this period, leading to a major shift in marine ecosystems as they were essential for providing habitats for many species.
4. The causes of the Late Devonian Extinction are still debated but may include factors like climate change, anoxic events (lack of oxygen in oceans), and possibly asteroid impacts.
5. Following this extinction event, marine life began to recover and diversify in the subsequent Carboniferous period, highlighting the resilience of ecosystems.

Review Questions

• How did the Late Devonian Extinction affect marine ecosystems and what evidence supports these changes?
  • The Late Devonian Extinction significantly altered marine ecosystems by causing widespread loss of biodiversity, particularly among coral reefs and fish species. Evidence from fossil records shows a dramatic decline in various marine organisms and shifts in community structure. The extinction event led to the collapse of reef systems which were vital for many marine species, demonstrating how interconnected these ecosystems were and how their disruption can lead to cascading effects.
• Compare and contrast the causes and effects of the Late Devonian Extinction with another major extinction event in Earth's history.
  • While both the Late Devonian Extinction and the Permian-Triassic Extinction had profound impacts on biodiversity, their causes differed significantly. The Late Devonian Extinction may have been influenced by factors like climate change and anoxia, whereas the Permian-Triassic Extinction is often linked to massive volcanic eruptions and climate shifts. Both events resulted in substantial losses of species; however, the Late Devonian led to a decline primarily in marine life, while the Permian-Triassic saw a more extensive impact on terrestrial life as well.
• Evaluate the long-term evolutionary implications of the Late Devonian Extinction on subsequent marine life.
  • The Late Devonian Extinction set the stage for major evolutionary changes in marine life as it eliminated numerous dominant groups such as placoderm fish and certain coral types. This created ecological niches that were later filled by new organisms, fostering greater diversification during the Carboniferous period. The recovery after this extinction event allowed for the rise of modern fish lineages and complex reef structures, illustrating how extinction can drive evolutionary innovation by reshaping ecological dynamics.

Related terms

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

Biodiversity: The variety of life in a particular ecosystem or on the planet as a whole, encompassing species diversity, genetic diversity, and ecosystem diversity.

Marine Ecosystems: Aquatic environments characterized by saltwater, which are home to various organisms including fish, corals, and other marine life.