The Evolution Of The Human Brain: This Is How It Developed In Our Ancestors
Our brain is one of our most complex and important organs, as well as one of the slowest to finish developing (and that does not take into account that throughout our lives we do not stop creating synaptic connections).
It is a structure present in a large majority of animals and that has been developing in different ways and evolving in different ways depending on the species over millions of years.
Focusing again on the human being, little by little different structures and capacities have emerged in our ancestors as evolution continued its course, currently the brain of our species is the last of the Homo genus that remains alive. In this article we are going to try to get closer to What has the evolution of the human brain been like until reaching the present day?
Analyzing what the brains of our now extinct ancestors were like is an arduous and complex task. In fact, a direct observation of a brain from species before ours (and even from ancestors within our own species) is not possible.
And the main problem in determining how the human brain has evolved is quite simple and at the same time extremely complex: the brain It is soft tissue, so it does not fossilize and ends up rotting and disappearing This implies that, with the possible exception of subjects who froze to death and were preserved in ice, the observation of a hominid brain is not directly possible.
This does not mean that assessing brain evolution in a way is impossible, there is even a science dedicated to it. We are talking about paleoneurology, which studies what the brain structure of our ancestors must have been like. based on the analysis of the endocranial structure
Thus, in the same way that paleontology is a scientific discipline despite studying aspects of reality of which only a few remains remain, in this case it is also possible to obtain scientific knowledge about organs that we can only know from what that surrounded them.
paleoneurology
The main element that allows us to try to observe how the human brain has evolved is cranial capacity, that is, the amount of brain volume that would fit inside a skull of a given species Not only size, but also morphology can give us clues about more or less developed regions.
Another aspect to take into account, and which in fact is also linked to the emergence and progressive increase in intellectual capacity, is the level of blood supply that these brains possess.
A functional brain requires a constant energy supply, functioning better the more efficient the supply of oxygen and nutrients. And this means that at a higher level of cranial capacity and greater brain functionality, much more energy and therefore more blood was necessary to carry basic nutrients to the brain. When we talk about fossils or bones, the simplest way to try calculating the blood flow level of our ancestors is through the observation of intracranial orifices that allow blood vessels to pass through it.
The development of the brain in the different species of hominins
Mainly based on the cranial capacity and its morphology, we are going to try to approximate how the human brain has evolved throughout evolution and in some of the most representative and well-known species of the hominin group, formed by the bonobos, chimpanzees, our bipedal ancestors and us, sapiens.
It should be noted that many of the following conclusions They are merely hypothetical, debatable and subject to multiple inferences
On the other hand, we must keep in mind that we still do not know well the evolutionary tree of our ancestors, since we only know it approximately from estimates (debatable and debated) about the position that each species occupies in the taxa of the evolution.
Ardipithecus ramidus
Ardipithecus is probably one of the oldest ancestors of humans ever found, although the Aahelanthropus tchadensis (about which there is disagreement as to whether it would be the first species of human or chimpanzee, and may even be the ancestor that distinguished both species) or the orrorin tugenensis are even older. This being, with simian characteristics, had a small skull of approximately 350 cubic cm (that of current chimpanzees ranges between 275 and 500).
This species was already bipedal, but its small brain makes the vast majority of higher cognitive abilities improbable at best. The fact that they lived collectively indicates a certain level of socialization, similar to that of the family groups of other great apes current. Knowledge of this species and its capabilities is limited.
The Australopithecus are a genus of hominid related to us, being one of the first types of hominin that existed after the Ardipithecus.
Among the different existing species, one of the best known is afarensis. This species It was characterized by a skull with a relatively small cranial capacity, of around 400-480 cubic cm (not being larger in size than a large number of chimpanzees although in size in proportion to the body it would be somewhat larger). The interior of the skull had different air cavities that protected the brain. There is a strong prognathism.
The morphology could reflect the existence of a relatively small frontal lobe, having few higher cognitive abilities and its reasoning and planning capacity being quite limited compared to a current human being. Nor did it have an excessively large parietal lobe, The existence of developed brain areas that would allow complex oral language is not likely and not possessing a high level of creativity or memory. Apparently the dorsal part of the skull was larger, something that is linked to the processing capacity of visual perception.
Homo habilis
He Homo habilis He was one of the first representatives of the homo genus. Homo habilis has a larger and somewhat more rounded skull, with a cranial capacity of around 600-640 cubic cm.
It has been discovered that this species was capable of creating crude tools, which requires a certain planning skill and a development of the frontal area somewhat higher than the previous species. It also requires greater hand-eye coordination, with the motor area probably being somewhat larger. The fact that remains have been detected that indicate that they hunted also suggests the ability to generate strategies and an improved level of communication.
The bulging of the parts of the cranial vault that correspond to Broca’s and Wenicke’s areas is observed, and the emergence of a very rudimentary form of language, strongly supported by gestures and visual communication in general, is not unlikely. There is probably a higher level of blood supply to the brain.
Homo erectus
The cranial volume of this species ranges between 800 and 1000 cubic cm, being this species the one that began to dominate and use fire as a tool. They created tools and hunted cooperatively. Although to a lesser extent than later species, probably They had a slightly more developed frontal lobe The lengthening of the back of the skull could indicate greater development of the occipital, parietal and temporal lobes.
Neanderthal man is our closest extinct relative and in fact coexisted with our species for thousands of years
The cranial capacity of Homo Neanderthalensis could be even greater than ours, reaching in its case between 1400 and 1900 cubic cm. This means that it is not known what level of abstraction they could reach. However, the morphology of its skull suggests a slightly smaller frontal than that of sapiens but at the same time a larger size of the regions of the occipital lobe, dedicated to bodily self-control and perception.
It is known that they took care of their sick, probably had a language similar to ours and sometimes carried out burials, in addition to dominating a relatively developed type of stone industry called the Mousterian stone industry. All of this implies that they had a language area and that They had the capacity for abstraction, empathy and a high degree of self-awareness
Homo sapiens
Our species, which has traditionally been considered the most evolved and intelligent, is characterized at the cerebral level by extensive development of the neocortex and especially by the enormous size of our frontal lobe. This is one of the elements that stands out the most in us and that allows us to perform and possess higher cognitive functions such as reasoning or abstraction.
Artistic creation was also long considered exclusive to our species, although it is currently considered that Neanderthals were also able to create different cave paintings and ornamental elements. When it comes to energy and nutrient consumption, it is estimated that our brain uses up to 20% of what we consume. It is also considered that The level of blood flow that our brain has has increased sixfold compared to the first hominids
However, our cranial capacity is smaller compared to that of Neanderthals, ours being around 1300 to 1800 cubic cm. Although their greater cranial capacity does not mean that they had more or less intelligence (depending largely on the organization of the brain and not only on its size), we cannot help but reflect that perhaps previous or different species were much more capable of what was originally thought, being something to value in the future.
