Avatarhood would have little meaning if it were not connected with the evolution. The Hindu procession of the ten Avatars is itself, as it were, a parable of evolution. First the Fish Avatar, then the amphibious animal between land and water, then the land animal, then the Man-Lion Avatar, bridging man and animal, then man as dwarf, small and undeveloped and physical but containing in himself the godhead and taking possession of existence, then the rajasic, sattwic, nirguna Avatars, leading the human development from the vital rajasic to the sattwic mental man and again the overmental superman. Krishna, Buddha and Kalki depict the last three stages, the stages of the spiritual development. Krishna opens the possibility of overmind, Buddha tries to shoot beyond to the supreme liberation but that liberation is still negative, not returning upon earth to complete positively the evolution; Kalki is to correct this by bringing the Kingdom of the Divine upon earth, destroying the opposing Asura forces. The progression is striking and unmistakable.
Though exactly not what Sri Aurobindo implied, someone else interpreted Dasavatharam as "Matsya (life in water), Koorma (amphibian), Varaha (land animal) , Narasimha (half man half animal denoting man evolving from his animal instincts), Vamana (the dwarf indicating the incompleteness of the development of man), Parasurama (uses axe so necessary to survive in forest), Sreerama (kingdom, use of bow and arrow meaning fighting from a distance rather than fighting at a close range using the axe), Balarama ( the agriculturist- man moving on to become a food producer) , Sreekrishna ( the advanced version of man - more intellectual - maybe the first known Consultant and Service provider) and yet to come saviour Kalki