What Was It Like When The First Humans Arose On Earth?
“Approximately 300,000 years ago, the first Homo sapiens — anatomically modern humans — arose alongside our other hominid relatives. It is unknown whether we descended directly from Homo erectus, heidelbergensis, or antecessor, although neanderthals, which came slightly later at 240,000 years ago, most certainly came from Homo heidelbergensis. Modern speech is thought to have arisen almost as soon as Homo sapiens did.
It took 13.8 billion years of cosmic history for the first human beings to arise, and we did so relatively recently: just 300,000 years ago. 99.998% of the time that passed since the Big Bang had no human beings at all; our entire species has only existed for the most recent 0.002% of the Universe. Yet, in that short time, we’ve managed to figure out the entire cosmic story that led to our existence. Fortunately, the story won’t end with us, as it’s still being written.”
For those of you who haven’t been following, this is now part 30 of my series on “what was it like when…” where I’ve been chronicling our natural history, from before the Big Bang up through the present day. Next week’s will be the final installment of that series, as we’ll arrive at the present!
This edition takes us from 65 million years ago to just 300,000 years ago: the development of modern humans. Come take a read; it’s the story of us all.
What Was It Like When Mammals Evolved And Rose To Prominence?
“65 million years ago, 99.5% of the Universe’s history had already unfolded, and yet the ancestors of modern humans were no better developed than a modern-day lemur. Complex, differentiated animals had already existed for half-a-billion years, but it seems to be mere chance that led to the rise of an intelligent, technologically-advanced species like us. We do not yet know what secrets other planets hold as far as life goes, but here on Earth, the most remarkable story of all was just getting truly interesting.”
It was some 550-600 million years ago that life’s complexity exploded, at least in the fossil record, at the start of the Cambrian period. While that epoch marks
the first complex, differentiated, macroscopic, multicellular, sexually-reproducing animals arising and dominating the oceans, life would go on to develop traits that were absolutely necessary for eventually giving rise to human beings. Animals developed spinal cords, four limbs, moved onto land, became warm-blooded, and more. Most importantly, many such creatures were able to survive enormous extinction events, enabling them to rise to prominence when a previously-occupied niche opened up.
It took half a billion years from the Cambrian explosion for mammals to rise to prominence, but after the big K-T extinction event, we were the most adaptable organism left. Here’s the story of how mammals like us evolved and came to dominate the Earth.