Continued from Inventing Humanity, last week on The Fire…
Let’s get started, shall we?
Standing Up To Evolution
It’s widely understood that ancient humans had to learn to walk upright, or bipedally, in order to improve their chances of survival in the unforgiving African savanna. This way we were able to keep alert for meandering dangerous animals ranging from Smilodons to hyenas while we hunted, gathered, and raised our families. This adaptation gave us the advantage to develop and enhance our tool making capabilities, conserve energy, and thus, develop larger brains.
In order for our ancestors to survive environmental changes of the Pliocene and thereafter they did away with their hindering quadrupedal habits and became mostly bipedal, and as the environment changed selection pressure was refined, as is the nature of evolution and life in general. Quadrupedal apes can expend up to 35% more energy than we do, and when food on the savanna is scarce, as it can be at times, this can become a death sentence. Another great adaptation our ancestors developed to this changing environment was a forward-facing big toe which helped support around 30% of our body weight.
It’s important to realize that features such a straight big toe and and renewed bipedal abilities are random genetic features in the grand scheme of things. Genetic mutations occur randomly. Some of these mutations turn out be prized and some turn out to be unpopular; just like the development of lungs in Devonian tetrapods like Tiktaalik eventually proved to be miracles that shaped the history of our world forever. These genetic mutations eventually alter the way in which we live our lives. Tiktaalik would eventually venture onto land, perhaps to escape predators, and our human ancestors would grow smarter and develop a diet richer in proteins from meat. A meaty diet also contributed to larger brains as the plant based diets of our robust cousins, Paranthropus, demanded more resources for the digestive system. The same reason cows have four stomachs. With the brain demanding such a significant percentage of our daily energy intake it was able to grow faster and make better humans. Better humans= better chances of survival.
Grade Ape Brain
Where would I be without my brain? Now that’s a question I cannot answer. Personally, my brain is quite an interesting place. A vast space of neurons and miracles set to give me the best life I can possibly have in relation to limits of my DNA. Some people compare human brains to the expansiveness of the universe because of how complex and miraculous it genuinely is. My brain is so amazing I can even talk to myself in it! That’s cray. I can also plan for the future, interpret abstract concepts, or even complete university programs with my big human brain. These natural gifts are quite extraordinary in nature, and also rare.
Our species has come such a long way in the last couple million years (still such a short amount of time in the history of life on earth) that it’s hard not marvel at the rate at which hominin brains have developed throughout time. I say this understanding how unfortunate it was that the dinosaurs never quite got the chance to develop into their full potential because of a stupid asteroid. GRRRR I hate that stupid asteroid that killed them, even though it made room for us. Why? Because I’m not selfish, that’s why. I know who the real legends of earth are.
Either way humans are very fortunate to have come as far as we have, although people begrudgingly acknowledge the average human brain size has decreased by 10% since the stone age² (Discover Magazine, September 2010). We also begrudgingly admit how much more complex the world has become due to this gift of ours, which causes serious trouble for us with issues related to environmental impacts and warfare. What other great ape can say they’ve killed members of their own species by the tens of millions using bombs, guns, gas, etc? What other animal can say they’ve nearly doubled the amount of carbon dioxide in the atmosphere in the last 80 years? Because although we are among the most intelligent species to inhabit the planet we are also one of the most destructive.
This is not to take away from the profound contributions the human mind has made to our lineage and survival, it simply sheds light on the negative effects of our gift. We used our brains to survive and we managed to do quite well, genetically speaking.
Good question, Isaiah. I guess we’ll just have to never find out because we’re all gonna die, because we’re all mortal and primitive 😉 . Some believe that our knack for engineering and robotics will eventually lead to cyborg, space traveling hominins and others believe our brains and eyes will get bigger and bigger as time passes due to environmental change. So maybe we’ll end up looking like the aliens we imagine. Some even believe the human race is on thin ice and may not make it too much longer into the future, not to mention nearly as long as Homo Erectus. But nobody knows for sure. That’s the thing about the future, isn’t it? It’s uncertain.
Regardless of what we imagine the future of human evolution to be we know that as long as people are reproducing and genetic diversity exists we will have a future. There will be a next evolutionary step. Hopefully that next step involves space travel and grand innovations, but I’m also ok with just plain, simple survival.
Thanks for reading and I hope you enjoyed this brief introduction to human evolution.