Before we started leaving our bones around to intrigue anthropologists a few billion years later, there were the cyanobacteria, which left stromatolites – precipitated calcium carbonate deposited in layers – as well as their distinct chemical footprints. Fast forward tens of hundreds of millions of years, breeze past a huge fossil record of living things large and tiny, plant and animal, bacterial and viral, and we start seeing remnants of creatures eerily similar to ourselves.
Between 7 and 6 million years ago, the skeletons left behind were different from the great apes who also occupied east Africa. Somewhere around 2.4 million years ago (give or take a couple hundred thousand years), Homo habilis and Homo rudolfensis became distinct from the remnants predominant before then. Around 2 million years ago, the bipedal Homo erectus was living and dying in the region. Around 850,000 years ago, Homo heidelbergensis distinguished themselves. Modern humans – Homo sapiens – crept into the picture around 200,000 years ago and have been improving on the original model every since, albeit slowly. What I’ve glossed over above is actually improperly abbreviated. Read the linked sites for more information. It is an astonishing story and one that deserves consideration by every one of us.
Given that humans started documenting themselves around 5,000 years ago and can only imagine our lives much before that, we must pay attention to the remains our truly ancient ancestors left us to ponder. The people who study this realm of human knowledge proceed cautiously, carefully, trying to make rational decisions about the remains they find. It is better to listen to their stories and read their research than it is to dismiss – or ignore – this fascinating, unimaginably long and incredibly complex process outright. While no single book, documentary, research study or perspective should be accepted without careful analysis, Dr. Donald Johanson has provided an estimable contribution through the website Becoming Human.
The Things We Leave Behind