Neandertals were the first evidence of caring and first basic of speech. Neanderthals lived in the ice age but they were exinct because humans could have possibly killled Neanderthals. Maybe it's because humans killed Neanderthals so humans can have more space or humans killed all the animals for food while the Neanderthals do not because humans have weapons more powerful than Neanderthals.
Who was our earliest ancestor? Why do Humans walk in 2 legs? Well Humans stand on 2 legs because about 6 million years ago human-like apes stand on 2 legs because they can see over tall grass to save energy or to hunt or carry food.
Homo Erectus, is an advanced hominid of homo habilis. Homo erectus lived 1.8 millions- 200000 years ago. They had bigger brains and bodies than homo habilis. The cause that may make the Homo habilis turn into homo erectus is climate change.