This theme seeks to connect trait evolution, trait function and gene networks to develop a “first principles” understanding of macroevolution through adaptation to drought and heat. Targeting the full range of variation between individuals and species, we compare patterns of change due to plasticity, with large-scale patterns of evolution in natural systems. Trait variation is connected with adaptation by examining associations between trait variation and climate within species (eg Themeda) and across clades (eg Eucalyptus), using field collection, common garden and glasshouse grown specimens. Theme 2 interlocks with theme 1 and 3 by exploring how key traits and mechanisms described in model species can be used in diverse clades to explain broad patterns of evolution.

Approaches vary from field collection of “soft” trait data, to experimental manipulation of plants designed to uncover recurrent patterns of trait and genetic evolution. Combinations of trait collection, physiological characterization and gene expression are used to explain the path from gene to adaptive evolution, while using phylogeny as a marker of the tempo and effectiveness of whole-plant adaptation to heat and drought.