Evolution and extinction can occur rapidly: a modeling approach.

Area of Science:

• Ecology
• Evolutionary Biology
• Systems Biology

Background:

• The Earth's fossil record over the last 500 million years shows evolutionary discontinuities, global extinctions, and species replacement.
• The underlying causes of these large-scale evolutionary patterns remain a subject of debate.

Purpose of the Study:

• To develop and analyze a model of evolutionary self-development for a large ecosystem.
• To investigate the potential for internal ecosystem dynamics to explain major patterns in the fossil record.

Main Methods:

• Developed a computational model of biota evolution based on universal laws of living systems.
• Incorporated principles of reproduction, density-dependent reproduction efficiency and mortality, mutational variability, and selection.
• Analyzed the model for emergent properties like bistability and transitions between states.

Main Results:

• The model demonstrates that global extinctions and biodiversity fluctuations (stasis, rapid growth) can arise from system bistability.
• Bistability was observed exclusively in model ecosystems with predominant sexual reproduction.
• Transitions between stable states are driven by the selection of the most adapted individuals.

Conclusions:

• The study suggests that major features of the Earth's fossil record can be explained by the internal dynamics of a self-organizing ecosystem.
• The emergence of sexual reproduction and associated adaptive diversification may be a critical factor in establishing ecosystem bistability.
• These findings link evolutionary mechanisms to macroevolutionary patterns observed over geological timescales.