The human brain across evolution.

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It is crucial to consider how the human brain has changed during evolution because we view the brain through the prism of evolutionary theory. Based on comparisons between the human and animal brains, we draw conclusions about how our own brain has evolved. One is that our brain has grown significantly in proportion to our body size. Animals that are older in evolution and more primitive have brains that are significantly smaller than their bodies. Consider the enormous bodies and tiny minds of the dinosaurs.

Despite the fact that our bodies are not much larger than those of chimpanzees, who are the closest living relative to us, our brains are around three times larger. Secondly, the brain has grown considerably more complicated. The intricacy of an animal's neural networks, rather than the size of its brain, determines how intelligent it is. Trillions of connections are made by billions of neurons. On the other hand, there is a correlation between brain size and complexity.

The expansion of the cortex is another way that the human brain has altered during evolution. Only mammals have the six-layered neocortex, which makes up the human brain's outer layer. Smaller mammals like hares, opossums, and armadillos have primitive cortices, while larger mammals like elephants, dogs, and dolphins have more advanced cortices. The cortex surrounds the entire brain in humans. The brain enables far more complex processing of sensory data (e.g. sight, sound, touch). Additionally, it enables more varied and adaptable behavioral reactions to both internal and external stimuli.

Cortex and subcortical regions can perform redundant or overlapping tasks. As an illustration, the frontal lobe and basal ganglia both control motor behavior. The basal ganglia, however, only control rather simple and rigid behavior. Although quick and effective, it is difficult to adjust to shifting circumstances. Contrarily, behavior controlled by the frontal lobe is significantly more complex, adaptable, and responsive to changing circumstances. However, compared to the basal ganglia, the frontal lobe frequently moves more slowly and uses more energy. Therefore, when walking down the sidewalk, we are content to rely on our basal ganglia, but when performing surgery or defusing a bomb, we would rather use our frontal lobe.

The frontal lobe has undergone the most significant structural alteration in the course of human evolution. Many smaller mammals, such as hedgehogs and tree shrews, have very small frontal lobes. They are nonetheless substantially less complex and smaller than in humans in higher-order mammals like cats and dogs. As was already established, the cortex's convolutions give dendrites greater surface area on which to grow. In a similar vein, our species possesses the most profound and complex cognitive abilities on the planet. However, this does not imply that other creatures do not engage in some sort of thought. In order to solve issues, chimpanzees use tools, and gorillas can be taught the basics of language. But from what we can tell, no other species really compares to us in terms of intelligence.

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