Scoliosis facilitates terrestrial feeding from grasses, trees, and bushes. Given the many benefits of bipedality which depends on a particularly formed spine, it is likely that selection for bipedalism played a large role in the development of the spine as we see it today, in spite of the potential for "scoliotic deviations". According to the fossil record, scoliosis may have been more prevalent among earlier hominids such as Australopithecus and Homo erectus, when bipedality was first emerging. Their fossils indicate that there may have been selection over time for a slight reduction in lumbar length to what we see today, favoring
Supernumerary body part Supernumerary body part Supernumerary body parts are most commonly a congenital disorder involving the growth of an additional part of the body and a deviation from the body plan. Body parts may be easily visible or hidden away, such as internal organs. Many additional body parts form by the same process as conjoined twins: the zygote begins to split but fails to completely separate. This condition may also be a symptom of repeated occurrences of continuous inbreeding in a genetic line. Specific types of additional body parts include: Vestigial structures are anatomical structures of organisms in a species which are