In natural populations fitness tends to vary even more than the definitions given to fitness, which says a lot. Variation in fitness proxies among individuals controls crucial parameters such as selection, rate of adaptive evolution, population growth rate, and the probability that a population persist in the face of environmental change. Different causes underlying this variation, however, can lead to different parameter values and different consequences. It is probably too ambitious, but I will try and explain how adaptive and neutral processes can both be elusive. I will discuss how to detect differences among individuals; whether neutral or selective processes explain cyto-nuclear discordant introgression; contemporary evolution, and, if time permits, the demographic consequences of adaptation.
I did my PhD and a first post-doc at the University of Zurich, Switzerland, working on the contemporary evolution and population dynamics of a wild rodent population. I am also interested in hybridization and genetic introgression.More on the "InterWeb": https://timotheenivalis.github.io//