1. Million of years ago human started moving around like any other living creature. 2. Then started developing climbing art. Climbing a tree was also evidenced fro fossil bone. 3. Man started to sit upright without taking support from arms on the base of his body weight. 4. Then human started to stand upright on the basis of knee and neck with the help of spine. 5. Lastly the humans who are known as Homo erectus learnt to walk upright.
Explanation:
Homo erectus are the first updated human species thereafter homo sapiens came. The upright movement and posture improved the early man's way of life. Million of years ago human started moving around. The they started the art of climbing, running.
After slow walk, running and climbing man became habituated with to sit on the balance of body weight without taking the help of the arms. Then man started to stand straight without to get bend on their spine. Walking, running, climbing and sitting all the postures are upright which were started from earlier age.
