These two strategies likely produced bifurcations and abrupt evolutuionary transitions to endothermy. I speculate that declining temperatures n the mid Triassic triggered endothermy in early mammal and avian lineages

When the costs and benefits of high body temperatures are combined, two strategies emerge: 1) save energy and be an ecotherm OR 2) spend as much as you need as an endotherm

I used a theoretical, energy-balance model to explore how and why an energetically expensive trait such as endothermy evolved multiple times among both plants and animals