How does Janus say that humanity emerged on Earth?

Janus said that three and a half million years ago, a cataclysm occurred that directly led to the emergence of humanity. The collision of two tectonic plates elevated the seafloor and separated the Atlantic and the Pacific. A chain reaction was set off that led to an ice age. Jungles began to shrink in West Africa. Some of the higher-order primates were driven from the trees onto the grassland. They began eating meat and their brains changed. They grew smarter and began making tools and hunting in packs. That was the beginning of humanity.