Paleoanthropological discoveries around the world show that both ancient and early modern humans are slowly and Continuously acquire new skills: master the use of fire, develop increasingly advanced blades, hand axes, flint and limestone tools, and create works of art.
A major driver of these cultural and technological advances that distinguish humans from other species is the evolution of the human brain.
brain expansion
The human brain is extremely special: large, compact, and more complex than the brains of any other species. In the past 6 million years, the size of the human brain has tripled, mainly occurring between 200,000 and 800,000 years ago, long before the appearance of Homo sapiens.
Why has human brain function expanded so much over the history of the human species? At first glance, the answer seems self-evident: a more developed brain would clearly allow us to achieve a level of security and prosperity that no other species on Earth can match. But the truth is more complicated. If there is indeed an indisputable benefit to survival for a brain as developed as ours, why haven’t other species developed similar structures over billions of years of evolution?
We need to carefully identify the mystery. For example, the eye developed independently along several different evolutionary paths. The eyes of vertebrates (amphibians, birds, fish, mammals and reptiles), cephalopods (squid, octopus, squid, etc.) have evolved, and some invertebrates have developed simpler monoculars, including Bees, spiders, jellyfish and starfish etc. The ancient ancestors of all these species, who lived more than 500 million years ago, seem to have only the most basic photoreceptors, capable of distinguishing light and dark.
But because accurate vision can provide unique survival advantages in different environments, complex eyes have evolved independently across different species, developing to suit each species’ specific habitat.
Similar traits evolve independently in different species, rather than existing traits from a common ancestor, a phenomenon known as convergent evolution. Such as the development of wings in insects, birds and bats, fish (such as sharks) and marine mammals (such as dolphins) have similar body shapes adapted to life underwater.
Obviously, different species have acquired similar beneficial traits in different ways, but the brain, the organ sufficient to create literary, philosophical and artistic masterpieces, to invent the plow, the wheel, the compass, the printing press, the steam engine, the telegraph, the airplane, and the Internet, does not belong here . Such brains have only evolved once, in humans. Powerful brains have such significant advantages, but why are they so rare in nature?
brain folds
Part of the reason for this puzzle is that the brain has two major weaknesses. First, our brain consumes too much energy, it only accounts for 2% of the body weight, and the energy consumption is as high as 20%. Second, the enlarged brain makes it difficult for the baby’s head to pass smoothly through the mother’s birth canal.
As a result, human brains are more compact or “folded” than those of other species, and babies’ brains are “semi-finished” at birth and require years of adjustment to mature. Therefore, human babies appear to be quite weak. Cubs of many other species can walk independently soon after birth and can quickly obtain their own food, while humans can walk stably for about two years after birth, and many years are required to achieve physical independence.
Given these flaws, how did the human brain develop in the first place? The researchers believe that a combination of factors may be driving this process. The ecological hypothesis holds that the evolution of the human brain stems from the environmental challenges encountered by the human species.
As the climate fluctuated and the surrounding animal populations changed accordingly, prehistoric humans with more developed brains were better at finding new food sources, devising new hunter-gathering strategies, and developing cooking and storage techniques that allowed them to move around in changing habitats. Survive and thrive in an ecological environment.
In contrast, the social hypothesis argues that within complex social structures, people increasingly need to cooperate, compete, and trade, giving a more developed brain an evolutionary advantage to better understand the motivations and predictions of others action. Similarly, the ability to persuade, manipulate, flatter, narrate, and please can be beneficial and help establish one’s social status, as well as stimulate the development of the brain that enhances the ability to speak and converse.
The cultural hypothesis emphasizes the ability of the human brain to absorb and store information so that knowledge can be passed on from generation to generation.
Another mechanism driving the evolution of the brain is sexual selection. Humans may have developed a preference for more-brained mates, even when the evolutionary advantage of the brain itself was not obvious. These sophisticated brains may reflect intangible qualities that are important for protecting and nurturing young children, and potential mates can infer such qualities from other perceivable traits such as intelligence, eloquence, quick response, and a sense of humor. exist.
evolutionary cycle
The evolution of the human brain is a major driver of uniquely human achievement, at least because it has helped enable technological advancements in increasingly advanced ways of harnessing the natural materials and resources around them. Technological progress, in turn, affects future evolutionary processes, allowing humans to adapt more successfully to changing environments and continue to develop and utilize new technologies. This is an iterative and intensified mechanism that brings about a rising tide of technology.
In particular, it has been suggested that mastery of fire allowed early humans to start cooking food, thereby reducing the energy required for chewing and digestion, not only making heat more accessible, but also freeing up intracranial space previously occupied by jaws and muscles, which are This drives the development of the brain. This feedback loop may have further fueled innovation in culinary technology, leading to continued brain growth.
Of course, the brain isn’t the only organ that sets us apart from other mammals, and neither is the human hand. Combined with the brain, the evolution of the hand also stemmed in part from the need to adapt to technology, particularly the benefits of creating and using hunting tools, needles and cooking utensils.
Specifically, when humans master the techniques of grinding stone tools and making spears, individuals who can use these tools powerfully and accurately will have better survival prospects. Better hunters can more confidently support their families and raise more children into adulthood.
The intergenerational transmission of these techniques has increased the proportion of skilled hunters in the population. More subsequent innovations, such as stronger spears, and later more lethal bows and arrows, also reinforced the evolutionary advantage of hunting skills.
Throughout history, virtuous circles of a similar nature have occurred: environmental changes and technological innovations have led to population growth, enabling people to adapt to changing habitats and new tools; new technology capabilities.
