A new 3-part documentary from the BBC pinpoints a commonly-asked question; how we, humans, came to be? what makes you who you are?
The documentary is presented and narrated by Dr. Alice Roberts who travels to Africa and to other high-tech modern laboratories to tell a story many of us are eager to listen to. Most of the time Dr. Roberts bring up comparisons of us against our closest relatives; chimpanzees. We share almost 99% of our genes with that family, and although we are not direct descendants from it, both of us are direct descendants of a common ancestor.
The first part of the series, titled BONES, Dr. Roberts tells us why our human physique is fundamentally different from that of apes. We have longer lower limbs and shorter arms. We can run fast, but we cannot climb trees. We can hold objects by one hand, while apes can hardly do that. The differences are evident in that they appear to be evolved in response to apes leaving the forests and heading to open plains. And why this happened in the first place is explained by a purely geological reason; Africa was getting drier and drier, and forests were diminishing, so apes were obliged to survive in the open fields of the savannah. Subtle, but critical, changes to the human body includes evolution and development of the gluteus muscles, especially the gluteus maximus, a muscle vital for running; our ankle joints no longer permit dorsiflexion to the levels seen in chimpanzees; our thumbs became more versatile, enabling us to hold objects easily with one hand, freeing the other hand for tool use.
The second part is titled GUTS. Most prior research has speculated that early homo species largely depended on meat for survival, and that was the reason their brains have become larger and larger over time. However, no definite evidence backs up this theory. Dr. Roberts does a comparison of a chimpanzee jaw and a replica of her own jaw. Her replica has shown that it could cut more efficiently through meat, as the teeth of humans appear to be narrower and thus sharper. On the other hand, another test demonstrated that human saliva has 6 times more amylase than that of chimpanzees; amylase is a crucial enzyme in starch digestion that initially occurs in the mouth. So, it seems that humans evolved to be as proficient carnivores as herbivores. However, the question still remains; which type of food was their primary source? To answer this question, Dr. Roberts travels to East Africa to meet an indigenous group living a primitive life. Those people are called Hadza, and Dr. Roberts thinks that their lifestyle is largely similar to that of early humans. After staying with them for a day, Dr. Roberts concludes that their hunter-gatherer lifestyle, the one early human speculated to had been, tends to lean towards the gatherer side. It’s realistic after all, because hunting large animals is not easy as it seems.
The final part is titled BRAINS. It’s obvious that our developed brains shape the way we behave as humans. But why would our brains develop so much, quadrupling in size in comparison with our earliest human ancestor, when such increase in size would demand excessive energy consumption? The answer lies in the fact that our early human ancestors faced a very tough environment to tackle. And it happened that each single brain development in the face of an obstacle led to the appearance of a skill, which itself opened up new doors to explore. From understanding eye language to sharing ideas, theories, and concepts in the form of names, to planning for tomorrow – such unique human abilities paved the way for us to colonize the globe.
You can download and watch this documentary by joining the MVgroup, a sharing community for documentaries. Here is the link.