When the Earth formed, 4.6 billion years ago, the Universe was already 9 billion years old; in other words, the Universe is three times as old as our home planet. For Earth's first billion years there was no life on the gradually cooling crust or in the primordial seas; then, some 3.6 billion years ago, bacteria-like organisms evolved, most likely in shallow, coastal waters or at "hot-smoker" vents along the mid oceanic ridges. It would be another 3.2 billion years, about 400 million years ago (MYA), that some plants and animals began to leave the ocean to colonize the land.
While the first mammals appeared in the Triassic Period, about 200 MYA, ancestral primates did not appear until the Paleocene Epoch, some 60 MYA. Another 52 million years would go by before hominids (the genus to which we belong) split from chimpanzees and man would not walk the Earth until 150,000 years ago (per the earliest estimate). Roaming about and living in small clans for most of our history, humans finally began to establish permanent towns about 10,000 years ago; this marked the rise of human culture, domestication, cultivation, established trade routes and our first significant impact on other species. Since then, advances in agriculture, industrial production, technology, communication and travel have led to the growing problems of habitat destruction, pollution, resource depletion and man-induced extinctions.
Put in perspective, the Human Era covers only the last 10,000 years of Earth's 4.6 billion year history. Yet, in that brief time, we have managed to place the future viability of our planet at risk. Some say we are the pinnacle of God's creation, the chosen species. Looking at the scientific evidence, one might argue that we were sent to destroy nature's handiwork; let's hope we evolve into more intelligent and insightful creatures before we fulfill that assignment.
