How long has modern man been here? It is thought that about five to six million years ago the succession of species that gave rise to us separated from the succession that led to the apes. From a common ancestor, the apes moved off in one direction and we, the hominids or family of humans, moved off in another. It is thought that the first genus of the hominids may have been Ardipithecus. It was followed by Australopithicus and finally our genus, Homo, which showed up between 1.5 and 2 million years ago. These were not Homo sapiens, however, but Homo rudolfensis, the earliest known member of our genus. These beings were not what we consider to be modern humans. In between the emergence of Homo rudolfensis and the eventual arrival of Homo sapiens (us), were Homo habilis, Homo ergaster, Homo erectus, Homo antecessor, and Homo neanderthalensis. It was in Africa, between 100,000 and 150,000 years ago, that modern humans, Homo sapiens (sensible humans), emerged. From there, we spread through Africa, into Asia and Europe, and to the rest of our world.
We began as and remained hunter-gatherers until about 12,000 years ago. At that time, with the domestication of plants and animals, our agrarian age began. We remained in that age until the late 1700s, when the Industrial Revolution began in England. By the mid 1800s, the Industrial Revolution spread to Belgium, Germany, France, and the United States. Eventually, it spread to all the industrial nations. By the middle of the 1900s we transitioned into a post-industrial high-technology age, which led directly to the information age that emerged in the latter part of the century. Through all these periods, our population continued to rise.
It took from the very beginning of the evolution of our species to the year 1900 for us to reach a population of 1.6 billion. Then something extraordinary happened. Something that will likely never again occur on this planet. From the year 1900 to 1960, our population jumped from 1.6 billion people to 3 billion. In sixty years, we nearly doubled the population that it took all of evolution to produce. Then, in the next thirty-nine years we added another 3 billion to reach a population of 6 billion in 1999. In other words, in 39 years, we added as many people (3 billion) as it took for our previous entire existence to accumulate. In a hundred years, from 1900 to 2000, we quadrupled our population. It is estimated that in 2050 our population will be about 9.2 billion. We are presently adding approximately 80 million people a year to our global population (estimated to be about 6.8 billion at mid 2009).