Biological diversity is to a large extent a matter of variation in overall size. The study of scaling relationships in biology has inspired hypotheses regarding regularities of growth, evolutionary trends, and underlying constraints on phenotypic diversification. One example is how morphological traits often covary within and among species according to simple power laws referred to as allometry. I am interested in the evolvability of allometries and to what extent allometries represent constraints on trait evolution. I am also interested in the types of selection that cause change in allometric parameters, and to what extent different types of traits show regularities in how they scale with overall body size.
The dominating view of evolution in the fossil record is that species remain more or less unaltered during their existence, with evolution only occasionally happening during speciation events. Such lack of evolution is referred to as stasis and does not rest well with the observation of high potential for evolution in contemporary populations, evidenced by artificial selection experiments, observation of numerous estimates of non-zero trait heritabilities and that natural populations commonly experience strong selection. These contrasting observations of evolution across different time scales, often referred to as the stasis-paradox, make the long-term history of life seem almost decoupled from the evolutionary process we study on shorter time-scales. A possible solution to the paradox of stasis lies in how we interpret the fossil record, and I am involved in projects where the goal is to understand if rates of evolutionary change are truly different across time scales and modes of evolution.
Causes of macroevolution change
Drivers of macroevolutionary change are inherently difficult to study in deep time, but abiotic factors are often suggested as the main agents causing long-term evolutionary changes. I am part of a team that uses Bryozoa to study the evolutionary importance of competition. Check out the BLEED web page for more info. I am also involved in other Red Queen related projects, testing to what extent long-term evolution in specific systems is driven by abiotic or biotic factors.