When man first appeared, 125,000 years ago, he had the same intellectual capacity that we have today. Though, like any human trait, intelligence varies between individuals, all healthy members of our species are equipped with the brain power to learn, to understand and to communicate; of course, some take more advantage of this potential than do others.
Our human ancestors used their intelligence to understand the nature of their environment, to gather food, to avoid danger and to protect themselves from the elements. Over time, experience and experimentation have greatly increased our knowledge but the innate intelligence of our species has not changed. Though we have the same intellectual capacity as those first humans who spread from Africa, the combined effects of curiosity, exploration, communication and hard work (mental and physical) have led to an exponential growth of our knowledge. Today's average high school student has a better understanding of many scientific issues than did the "great minds" of past centuries; human knowledge is a group effort to which the individual both subscribes and contributes.
Of course, the acquisition and communication of knowledge can pose a threat to some groups and, throughout history, they have attempted to block our progress; politicians, dictators and religious leaders come to mind. If we don't destroy our planet first, evolution will eventually free us from those human constraints.
