A new Darwinian hypothesis goes like this: “As human ancestors went from swinging through trees to walking on two legs, they may have received a boost from an unlikely source: ancient supernovas.
These powerful stellar explosions may have showered Earth with enough energy to shift the planet's climate, bathing Earth in electrons and sparking powerful, lightning-filled storms, according to a new hypothesis.
Lightning then could have kindled raging wildfires that scorched African landscapes. As savanna replaced the forest habitat, early humans that lived there may have been pushed to walk on two legs, the new study suggest."
But then live science tells us that we should not jump to conclusions just then. As it tells us, the evolution of bipedalism is could have occurred earlier.