Dissecting global diversity patterns: examples from the Ordovician Radiation

Area of Science:

• Paleontology
• Geology
• Evolutionary Biology

Background:

• Life's history shows intermittent radiation events, but causes may not be globally uniform.
• Major diversity increases can result from combined mechanisms acting at various scales.

Purpose of the Study:

• To review ongoing research on the Ordovician Radiation's manifestations across multiple scales.
• To explore the interplay of geographic, environmental, and intrinsic factors during this diversification interval.

Main Methods:

• Review of outcrop-based research, particularly in North America.
• Analysis of stratigraphic records, focusing on the Great Basin.
• Examination of diversity patterns in relation to tectonic activity and environmental changes.

Main Results:

• Diversity was concentrated near mountain building and volcanic regions, indicating a link to tectonic activity.
• Tectonic activity had varied impacts, being detrimental to some life forms while beneficial to others.
• Biotic transitions in high-quality local records occurred faster than global averages, suggesting asynchronous global changes.
• Environmental and geographic ranges of Ordovician genera increased, pointing to intrinsic factors.

Conclusions:

• The Ordovician Radiation was a complex event driven by multiple factors at different scales.
• Tectonic activity and intrinsic factors played significant roles in shaping Ordovician biotic patterns.
• Global diversity patterns may mask rapid, asynchronous local diversification events.