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Translational Rabbit Model of Chronic Cardiac Pacing

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Morphospace expansion paces taxonomic diversification after end Cretaceous mass extinction.

Christopher M Lowery¹, Andrew J Fraass^2,3

¹University of Texas Institute for Geophysics, Austin, TX, USA. cmlowery@utexas.edu.

Nature Ecology & Evolution

|April 10, 2019

Summary

The fossil record shows that after mass extinctions, species diversity recovery is limited by the time it takes for evolutionary innovations to rebuild ecological niches. This "morphospace reconstruction" explains delayed speciation and diversification rates.

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Area of Science:

Paleontology
Evolutionary Biology
Climate Science

Background:

Mass extinction events significantly impact global species diversity.
The fossil record indicates delayed speciation following extinctions, a phenomenon poorly understood.
The morphospace reconstruction hypothesis suggests that extinctions reduce ecological complexity, delaying recovery.

Purpose of the Study:

To test the morphospace reconstruction hypothesis using planktic foraminifer data.
To investigate the relationship between morphological complexity and species diversity recovery after the Cretaceous-Palaeogene mass extinction.
To understand the factors driving diversification rates after major extinction events.

Main Methods:

Analysis of highly resolved palaeontological records.
Examination of the morphological complexity of planktic foraminifer tests.
Correlation of morphological complexity changes with species diversity shifts.

Main Results:

Increases in morphological complexity preceded significant changes in species diversity.
Early diversification was linked to the refilling of existing ecological niches with complex forms.
Major increases in complexity were driven by evolutionary innovations, opening new niche spaces.
The rate of diversity recovery was paced by the rebuilding of morphospace.

Conclusions:

Morphospace reconstruction is a key factor limiting the speed of biosphere recovery after mass extinctions.
Evolutionary innovations that create new morphospace are essential for subsequent diversification.
There is a fundamental speed limit on diversification imposed by the time required for evolutionary innovation and niche construction.