There is at least one rather specialised area in which theory offers predictions - evolution of communities. It's like, 'when true grasses appeared, they made, through having some novel features, created grasslands. They circumvented successions that would lead to preexistent plant habitats; in the beginning, they were weeds compared to the rest of vegetation. Nowadays, we have a group of species that spread widely, are considered weeds and share ecological similarity, not [relatively recent] common ancestor. We predict that in future, these weeds will form habitats through disruption of current eco networks.' Admittedly, this is hard to observe.