The anatomically modern human has been around for less than 50 thousand years. On the timescale of all life on our planet, that is an exceptionally small period of time. Some animals, such as the horseshoe crab, have barely evolved in the past 450 million years! That’s 9000 times longer than we’ve been here, so how come man has walked on the moon and the horseshoe crab hasn’t? how come man has created a global civilisation? And how come we did it in such a short period of time? The key to this mystery dates back roughly 2 million years, to the discovery of fire by the first human species, Homo Erectus. Fire has shaped our behaviour and helped develop our brains. It has acted as a catalyst in the advancement of our species. It has been the key that opened the door to living on the ground rather than in the treetops. It is no coincidence that the Greek’s believed fire to be the element of the gods. When Prometheus gave fire to man and was eternally punished, it was because he gave us the power to transcend into higher beings. So, how is fire so significant? How has it allowed us to create such an established place for ourselves on this world?
Fire and Food
The first and more obvious reason that fire allowed us to adapt so fast is that it gave us the ability to cook our food. Cooking breaks down starches and fibers and denatures proteins, as well as killing off many harmful pathogens and parasites. This makes the process of digestion extremely more efficient, allowing us to digest up to ten times as much nutrition from our food as if it was not cooked. The result is that we humans are taking in vast quantities of energy in smaller periods of time, so we spend less time hunting and foraging, and more time playing, learning, and creating. This resulted in the human brain developing at a remarkable rate, with every generation going beyond the last, making tools, farming, creating societies etc.
Fire and Sleep
The other reason the discovery of fire was such a monumental turning point for mankind is a slightly more obscure one. Most, if not all, of the Hominid species before us slept in the treetops, because the dangers of sleeping on the ground were too much. Large carnivores and dangerous parasites lurked on the ground, which was too high of a risk to take, but with fire the carnivores were deterred, and the smoke would also drive away the parasites. But what’s the significance of being able to sleep on the ground in stead of in the trees? We have to go a little further into the process of sleep to find the answer.
There are 2 types of sleep in the sleep cycle of mammals and birds, NREM (deep sleep), and REM (dream sleep). Both types of sleep are crucial for the brain, but deep NREM sleep will always take priority – it seems to control the majority of sleep benefits in a large block, whereas REM sleep refines the small details in the brain, and is essential for learning and emotional development. However, during REM sleep the body is induced into a state of absolute paralysis, and this is very dangerous if you are sleeping in the trees, which is one of the main reasons that other hominid species have low levels of this REM dream sleep in their cycles. This makes the ability to sleep on the ground immensely advantageous, especially for brain development. As Homo Erectus speciated from its last ancestor after discovering fire, it gradually soaked up more and more dream sleep every night, and therefore the brain of Homo Erectus became acutely more advanced.
The other, even less evident advantage to sleeping on the floor was, strangely, because it was such a dangerous place to sleep. This resulted in the human sleep cycle being much shorter than the 15 hours our ancestors were having. It became a selective advantage to be able to get a higher quality of sleep in a shorter duration, so that we were exposed less to the predators and the parasites of the ground. So once again, we humans had yet more waking hours to learn and play and innovate.
Because of fire, not only were we able to spend huge amounts more time socialising, learning, and creating, but we also were able to consolidate the things we learned during day, and also build up our emotional intelligence due to the greater levels of REM sleep we were getting. This has resulted in humans creating a worldwide civilisation with incredible speed, and has led to us discovering many other essential things such as electricity, which has unified our society. Our established place on planet Earth grows every day as we learn at an exponential rate, and it all started with the discovery of fire.