Final answer:
Natural selection played a pivotal role in developing the human nervous system by favoring traits that improved survival, such as rapid response to danger, cognitive functions, and activation of the immune system.
Step-by-step explanation:
Natural Selection and the Human Nervous System
Natural selection has significantly shaped the human nervous system, contributing to its complexity and efficiency. The nervous system coordinates all of the body's voluntary and involuntary actions, including rapid responses to stimuli such as moving away from danger, retaining memories, and regulating emotions. Throughout human evolution, those with more effective nervous systems had an increased chance of survival, as they could better avoid hazards and remember vital information.
When we compare the human brain to that of our closest evolutionary relatives, like chimpanzees, we notice a significant increase in size. This increase indicates an evolutionary trade-off, where humans may have sacrificed muscle mass to provide enough energy for a larger brain, which in turn required more energy for its maintenance due to increased neurological tissue. The survival benefits of higher cognitive functions, problem-solving abilities, and social interactions were likely the driving forces behind the evolution of the human nervous system under the pressures of natural selection.
In an environment where wounds were frequent and could be lethal, the evolution of the nervous system's activation of the immune system demonstrates natural selection’s impact on survivability. The ability to quickly respond to injuries by activating healing processes would provide a selective advantage, as it would allow individuals a better chance of recovery, thus enhancing the likelihood of reproducing and passing on those successful traits.