Humans were once insignificant animals with little impact on their environment (Harari p. 4). However, the occurrence of certain revolutions resulted in humans quickly rising above all other species with large impact on nature and its ecosystem. These included the cognitive revolution, agricultural revolution, and the scientific revolution. The first of these was the cultural revolution which started 70000 years ago (Harari p. 3). The cognitive revolution is described as the time when humans first began to show cognitive traits that differentiated from other species. The result of this was a development of culture, religion, and a societal cohesiveness that allowed an unprecedented number of members of the same species to collaborate towards a common goal. The second revolution that sped up the influence and spread of humanity was the agricultural revolution which began approximately 12000 years ago (Harari p. 3). The agricultural started the shift of multiple human tribes from hunter-gatherers to farmers. This was a gradual shift in behavior that increased the number of food per territory which resulted in an exponential increase in the population of Homo sapiens (Harari p. 83).
There are several theories that explain why homo sapiens became dominant. The first is what Harari terms the “there-is-a-lion-near-the-river” theory. This describes the advantages contained in the human language in comparison to communication protocols used by other species including similar human species. Homo sapiens were capable of ingesting, storing, and communicating a prodigious amount of information about the surrounding world (Harari p. 22). This allowed homo sapiens to describe exactly where predators were seen, the time, and its surroundings which allowed the species to more efficiently determine how to handle a threat if needed. The second theory is the gossip theory which boosted the maximum number of individuals a community could contain and successfully collaborate (Harari p. 24). This mainly included information about who could be trusted and allowed homo sapiens to form larger and more stable bands (Harari p.27). The final theory described the appearance of fiction or imagined orders. This allowed even larger communities of homo sapiens to communicate together, above the previous threshold of 150 individuals (Harari p. 27). By believing in common imagined orders such as gods, nations, currency, human rights, laws, or justice a large number of strangers would be able to cooperate (Harari p. 28). This allowed sapiens to trade with currency and fight for common beliefs in human rights with individuals they have never met. By sheer numbers homo sapiens were able to eventually dominate other species that were much more limited in their ability to collaborate.