QLS Featured Seminar Series - Dr. Gregor Fussmann

Adaptive and Non-Adaptive Dynamics

Gregor Fussmann

Department of Biology, McGill University

The dogma in evolutionary biology is that the characters of organisms change over time in a way that increases organisms’ fitness. This process has been graphically compared with (and mathematically analyzed as) “climbing an adaptive hill.” There are many empirical examples for this adaptive view of evolution – particularly from experimental evolution studies in the laboratory. More recent, critical inspection of results reveals that there are also a large number of counter examples (mostly from natural environments), where organismal traits change without affording any apparent increase in fitness.

I present some examples of adaptive and non-adaptive change from my own experimental studies. I then present a simple mathematical model that might explain why we often observe non-adaptive states in nature. The solution evokes transient evolutionary dynamics that pass through non-adaptive states before they reach their final adaptive endpoint.