🧬 What is “fitness”?

The term “fitness” is thrown around all the time in ecology and evolutionary biology. But what does it exactly mean? This kind of question calls for a philosopher (which I am not). To get at this question, Dr. Joanna Masel and I teamed up with some philosophers to investigate! Ultimately, we propose that there are two different “types” of fitness evolutionary biologists refer to in models: (1) short-term fitness, which are summaries of vital rates (e.g., the Malthusian parameter) and (2) long-term fitness (e.g., the probability an allele fixes in a population). The below figures summarizes our view of fitness and its operationalizations. See our preprint for details.

Our “fitness” schematic. Link to article on EcoEvoRxiv

Here is a link to an excellant talk by Dr. Joanna Masel on this project and related works that elegantly summarizes many of our views.

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