Life on Earth is characterized by a profusion of diversity; Darwin’s “endless forms most beautiful and wonderful”. However, phenotypic diversity is not continuous; organismal design space exhibits a decidedly clumpy occupation. The material basis of this discontinuous phenotypic variation has been the subject of debate since the time of the Ancients, but it has been difficult to obtain general insights for lack of an integrated quantitative approach to characterizing phenotype and testing causal explanations rooted in development, evolution, function and the environment.
Here we propose a program of research that will uncover the causal bases of morphological evolution and diversity, addressing whether selection is driven towards predictable outcomes, triangulating on optimal solutions, trade-offs among optimal solutions, and/or bounded by biological constraints.
To achieve this we will (i) develop a novel computational pipeline that creates theoretical morphospaces; (ii) subject theoretical morphologies to functional analysis to obtain performance landscapes; that will (iii) be interrogated to infer which designs occupy optimal performance zones and then (iv) determine whether organisms evolve towards these optimal designs.
Our understanding of convergence and constraint is hindered by the lack of a rigorous framework for assessing causal mechanisms between clades and in deep time; our project will rectify this. We will determine the causal mechanisms of morphological diversity in three organ systems that have evolved convergently, constitute key innovations that underpin the evolutionary success of their respective clades and exhibit clear but competing functional adaptations: vertebrate jaws, animal wings, and plant leaves. Our project will develop the first rigorous organ-system wide means for documenting the causal basis of morphological form, via a computational pipeline that will be made freely available to the community.
