Final answer:
The shift to upright walking among early Homo genus members resulted in dietary changes to easier-to-digest foods, which provided the necessary energy for brain development.
Step-by-step explanation:
One of the consequences of the digestive organs moving lower and into a smaller space when members of the Homo genus began walking upright was that it led them to adopt foods that were easier to digest. The anatomic changes that came with an upright posture necessitated a change in diet from tough plants to more digestible foods like nuts, fruits, tubers, honey, and meat. This dietary shift provided the energy required by a growing brain and a more active lifestyle. Consequently, adopting a diet that included high-energy foods such as meat became advantageous for early hominins, like Homo erectus, and supported greater brain development over time according to the "expensive tissue hypothesis".