![chimpanzee hand like feet chimpanzee hand like feet](https://i.pinimg.com/originals/19/8e/e3/198ee30ca890db61af9de5b67a1cf2f4.jpg)
The early human ancestral lineage(s) has, therefore, commonly been evaluated with respect to the extant chimpanzee. With the advent of genome-wide molecular studies, chimpanzees have been shown to be genetically the most similar, and phylogenetically closest, to humans (and equally so is the bonobo). This accords with the known fossil evidence, including the recently reported hominin fossils which have been dated to 4.4 million years ago. In hominins, a separate adaptation, involving the neural separation of the big toe, apparently occurred with bipedality.
#CHIMPANZEE HAND LIKE FEET MANUAL#
This early adaptation laid the foundation for the evolution of manual dexterity, which was preserved and enhanced in hominins. These observations suggest that the brain circuits for the hand had advanced beyond simple grasping, whereas our primate ancestors were still general arboreal quadrupeds. Humans, by contrast, had an independent neurological representation of the big toe (hallux), suggesting association with bipedal locomotion. In the monkeys, the somatotopic representation of the toes was fused, showing that the digits function predominantly as a unit in general grasping. The neural mapping of the subjects’ toes differed, however. This reflects the ability to use each digit independently, as required for the complex manipulation involved in tool use. In both humans and monkeys, we found that each finger was represented separately in the primary sensorimotor cortex just as they are physically separated in the hand. Contrary to the ‘hand-in-glove’ notion outlined above, our results suggest that adaptations underlying tool use evolved independently of those required for human bipedality. In this study, we sought to shed new light on the origins of manual dexterity and bipedalism by mapping the neural representations in the brain of the fingers and toes of living people and monkeys. Either way, it is commonly thought that one led to the other.
![chimpanzee hand like feet chimpanzee hand like feet](http://3.bp.blogspot.com/-Xz6mMoyjEr4/Tgodm_jLLTI/AAAAAAAAByo/y3_X_KlN9Ls/s400/michele-bachmann-bikini.png)
People have long speculated whether the evolution of bipedalism in early hominins triggered tool use (by freeing their hands) or whether the necessity of making and using tools encouraged the shift to upright gait.