\" \" Homo erectus specimen at the Smithsonian Natural History Museum. David H. Koch Hall of Human Origins ( CC By-SA 2.0 The reconstructed skull of aspecimen at the Smithsonian Natural History Museum. About 20 human species have roamed this planet over the past 7 million years or so, and all but one — here's looking at you! As a species, Homo erectus might have gone extinct because it simply couldn't get its act together. According to Shipton, the sheer laziness of Homo erectus can be observed in the manner in which they made their tools.