Evidence of self-organization in planktic foraminiferal evolution

Planktic foraminiferal evolutionary data was anlalyzed using techniques of nonlinear dynamics by
R. Timothy Patterson of Carleton University and Anthony D. Fowler of the University of Ottawa.
The data set comprised 196 extinction and speciation horizons from biostratigraphic ranges of 662 reliably defined species. Extinction and speciation data sets were both well characterized by power-law models.

Planktic foraminifers are floating single celled organisms. They are predominately marine and are protozoans (i.e. single celled), belonging to the subclass Sarcodina, order Foraminifera. They are characterized by a test of one to many chambers composed of calcite or of aggluginated particles. They range from the Cambrian to the present.

The analysis was interpreted to be consistent with planktic foraminiferal evolution being organized,
as opposed to randomly driven. Their data supports a model whereby "the internal organization of an ecosystem regulates the response to changes in a deterministic manner, the relative scales of disturbances and extinctions depending on the degree of interdependency within the system".

Graphs of their data showing number of species versus extinction and speciation events, are shown below.

As can be seen in the graphs , power-law distributions are apparent in both the extinction and speciation data sets, similar to the "real life" extinction events studied in tthe Phanerozoic by Raup and the computer simulated extinctions created by Ray. As well a very large set of data points, at the species level, were used which lend credibility to the findings.

Final thoughts on complexity
Complexity index