Final answer:
The evolutionary relationship between walking, running, speed, and bipedalism is influenced by anatomical changes over time. Bipedal hominins have undergone changes such as angling of the femur, spinal curves, foot arch evolution, and realignment of the big toe. Homo erectus was efficient at bipedal locomotion.
Step-by-step explanation:
The evolutionary relationship between walking, running, speed, and bipedalism is complex and influenced by various factors. Bipedal locomotion, where organisms move using two legs, has evolved through anatomical changes over time.
One important anatomical change is the angling of the femur inward, which positions the knees and feet under the center of the pelvis. Bipedal hominins have also developed spinal curves that help balance the weight of the upper body, the evolution of the arch in the foot, and the realignment of the big toe parallel to the other toes.
As speed of locomotion increases, the time that both feet are on the ground decreases, with running involving both feet leaving the ground. Homo erectus, an early Homo species, was nearly as efficient at bipedal locomotion as modern humans, with a broader pelvis, longer legs, and arched feet.