Life on earth has evolved through a series of transitions, each of which involved independent replicating units forming groups that reproduce cooperatively. For example, organelles evolved through the union of different unicellular organisms, multicellularity evolved by cells joining together, and multicellular organisms joined to form societies. Recent research has highlighted that these transitions in complexity have played a crucial role in overcoming ecological barriers at all levels of life, from bacteria resisting antibiotics by forming biofilms to vertebrates coping with harsh environments by living in cooperative societies. This is a significant advance, as it helps explain the way complex life has evolved and how new ecological niches are created and colonised. However, why some lineages make the transition to higher levels of cooperation while other do not, and why some lineage reverse to a less social life is unclear. To resolve this issue we have a number of projects examining the transition from solitary to cooperative living across the tree of life. Specifically, we have the following ongoing projects examining: 1. The evolution of multicellularity in green algae using comparative genomics. 2. The evolution of cooperative breeding across birds using comparative genomics. 3. The genomics of heat tolerance and cooperative breeding in ostriches, Struthio camelus.