Life simulation or Artificial life, is about maintaining and growing a manageable population of organisms. The player is given the power to control the lives of autonomous people or creatures, sometimes over generations.
Sub-genres
God Game
The player assumes the role of a divine entity with a focus on managing tribal worshipers. Players are unable to tell specific units what to do and must utilize supernatural powers to influence the world.
Manage a population of creatures over several generations to try and achieve goals for the species as a whole. Players are able to crossbreed creatures, which have a set of genes or descriptors that define the creature's characteristics. Some games also introduce mutations due to random or environmental factors, which can benefit or harm the population as creatures reproduce.