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Biological extinction in earth history
1Department of the Geophysical Sciences, University of Chicago, IL 60637, USA.
Science (New York, N.Y.)
|March 28, 1986
Summary
Mass extinction events are crucial for life's evolution, shaping biodiversity through selective elimination of species. Understanding these events helps us deduce causes and their impact on Earth's history.
Area of Science:
- Paleontology
- Evolutionary Biology
- Earth Science
Background:
- Extinction is a fundamental process in the history of life, with virtually all species eventually perishing.
- Mass extinctions, particularly the five largest over the past 600 million years, significantly impact evolutionary trajectories.
- Extinction events can be episodic, interspersed with periods of relative stability, and often exhibit biological selectivity.
Purpose of the Study:
- To highlight the critical role of extinction in the evolution of life.
- To examine the causes and patterns of both major and minor extinction events.
- To analyze the selective nature of extinction to deduce proximal causes.
Main Methods:
- Analysis of past extinction events, focusing on the five largest mass extinctions.
- Investigation of smaller extinction events to identify patterns of biological stress.
- Comparative analysis of victims and survivors of extinction episodes.
Main Results:
- Extinction is a pervasive force, shaping life's evolution across various scales.
- Extinction events are often selective, offering insights into their underlying causes.
- Commonly cited causes include sea-level drops and climate change, with extraterrestrial impacts gaining traction.
Conclusions:
- Extinction plays a pivotal role in evolution, potentially driving constructive evolutionary change.
- Understanding extinction selectivity is key to deciphering its causes.
- Extinction events can be viewed as perturbations that eliminate susceptible organisms under rare geological stresses.
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