How our species evolved is a matter of great interest to academicians and lay persons. How, when and why we parted ways, genetically speaking, from our nearest cousins-the chimpanzees and bonobos, is a mystery waiting to be solved. Thirty hypotheses have been proposed for the possible reasons why we became bipedal and far less for the emergence of sclera (the white of your eyes), loss of baculum (penis bone found in many placental mammals), loss of estrus and emergence of concealed ovulation, the three-fold increase in brain size, the loss of body hair and, above all, the emergence of cognitive thinking.
Recently, one of the oldest and most complete skeletons of humankind’s ancestors was unveiled in South Africa. With great pride and perseverance, the team of researchers unveiled a near-complete fossil hominid skeleton (over 3 million years old) at the Evolutionary Studies Institute vault at the University of the Witswatersrand in Johannesburg, South Africa. This article seeks to present the significance of ‘Little Foot’- the name given to the small foot bones discovered by Professor Ron Clarke in 1994 when he was sorting through bones obtained from a cave system in South Africa.
The structure of the four ankle bones indicated that the owner was able to walk upright. Due to the small size of the bones, they were dubbed “Little Foot”. The rest of Little Foot was found embedded in the calcified ancient cave and the recovery of the bones proved extremely difficult because they were completely embedded in concrete-like rock. The team spent more than 20 years excavating, cleaning and putting together the skeleton of Little Foot.
The fossil is of Australopithecus species — the diminutive, ape-like human ancestors that roamed this part of Africa millions of years ago. This would mean Little Foot was alive about 500,000 years before Lucy, the famous skeleton of an ancient human relative found in Ethiopia. Both Little Foot and Lucy belong to the same genus – Australopithecus – but they are different species. It means our ancient ancestors were more widely scattered across Africa than previously thought. It also suggests there were a diverse number of species. Little Foot was discovered in the Sterkfontein caves, north-west of South Africa’s main city Johannesburg. It is thought that she was a young girl who fell down a shaft of one of the caves. The full skeleton of Little Foot, as she is known, proves that she is more like us than an ape, with shorter arms and small hands. To avoid predators she probably slept in trees (similar to today’s living chimpanzees and gorillas that make sleeping nests). She walked upright but searched for food in the trees during the day with the help of grasping movements by her foot made possible due to the still opposable big toe. How she fits into our family tree is still a work in progress.
If she was walking upright while still having a tree-based habitat, it implies that all the hypotheses of why we became bipedal need to be revisited. It takes us to another part of the globe, the Primate Research Institue, Kyoto University, Japan.
In 2013, two researchers Tomoko Imura and Masaki Tomonaga presented a paper on the differences between chimpanzees and humans in visual processing. Their conclusion: the ability to integrate local visual information into a global whole is among the unique characteristics of humans. In other words, humans have a superior ability to integrate spatially separate visual information into an entire image. The findings suggest that humans exhibit global precedence while chimpanzees exhibit local precedence. Global precedence occurs when an individual more readily identifies the global feature when presented with a stimulus containing both global and local features: local precedence occurs in the opposite. Put simply, it means we see the forest first while the chimpanzees see the trees(or the bananas!) first. Does this feature of visual processing offer any leads to solve the mystery of how we evolved. Any clues here, Mr Detective?
(The author is serving as the Spl. DGP in the Police Headquarters, Jammu.)