Late devonian extinction

Definition

The late Devonian extinction refers to a series of extinction events that occurred during the late Devonian period, approximately 375 to 360 million years ago, resulting in the loss of around 70-80% of all species on Earth. This event significantly impacted marine life, particularly reef ecosystems, and is considered one of the five major mass extinctions in Earth's history.

5 Must Know Facts For Your Next Test

1. The late Devonian extinction unfolded over several million years and involved multiple phases of extinction rather than a single catastrophic event.
2. The extinction primarily affected marine species, particularly those living in shallow waters and reef environments, leading to a dramatic decline in biodiversity.
3. Key groups affected included brachiopods, corals, and certain fish species, with some families never recovering after the event.
4. Possible causes of the late Devonian extinction include global cooling, anoxia in ocean waters, and changes in sea levels that impacted marine habitats.
5. The late Devonian extinction had lasting effects on the evolution of surviving species, paving the way for new dominant groups in the Carboniferous period.

Review Questions

• What were the major characteristics of the late Devonian extinction and how did it impact marine biodiversity?
  • The late Devonian extinction was characterized by a gradual decline in marine species over several million years, ultimately leading to the loss of around 70-80% of all species. This event had a profound impact on marine biodiversity, particularly among shallow-water organisms and reef-building species. The decline in diversity disrupted entire ecosystems, leading to changes in food webs and habitat structures.
• Discuss the potential causes behind the late Devonian extinction and their effects on Earth's ecosystems.
  • Several potential causes have been proposed for the late Devonian extinction, including global cooling events that led to reduced temperatures and altered climate patterns. Anoxia in ocean waters created low-oxygen zones detrimental to marine life. Additionally, fluctuations in sea levels affected coastal habitats and ecosystems. These factors combined likely contributed to significant stress on marine environments, ultimately resulting in widespread extinctions.
• Evaluate the long-term implications of the late Devonian extinction on evolutionary patterns observed in subsequent geological periods.
  • The late Devonian extinction had far-reaching implications for evolutionary patterns in later geological periods. The loss of dominant groups such as certain coral and brachiopod species opened ecological niches for new organisms to evolve and thrive. Surviving groups diversified rapidly during the Carboniferous period, leading to an explosion of terrestrial life forms. This shift set the stage for future evolutionary developments, including the rise of amphibians and early reptiles, fundamentally shaping Earth's biological history.

Related terms

Devonian Period: The Devonian Period is a geologic period that lasted from about 419 to 359 million years ago, known as the 'Age of Fishes' due to the diverse fish species that evolved during this time.

mass extinction: A mass extinction is a relatively short period in geological time when a significant percentage of all life on Earth becomes extinct, usually due to catastrophic environmental changes.

Frasnian-Famennian Boundary: The Frasnian-Famennian Boundary marks the end of the Frasnian stage and the beginning of the Famennian stage within the late Devonian, coinciding with one of the most severe extinction events.