Thought humans evolved directly from our ape cousins? Not so.
We humans weren’t around 3.8 billion years ago, when scientists estimate the first life form appeared on Earth, and we don’t know precisely how life began. What we do know is that, as with all animals, evolution turned us into what we are today through a series of small changes over a long period of time.
However life started, we can see via microfossils (fossils too small to view with the naked eye) that microbes, which are tiny, single-cell organisms, were among the earliest arrivals, helping to landscape rock formations in South Africa and Australia. Microbes are still around—according to the American Society for Microbiology, you have more microbes on one hand than there are humans on the planet Earth. They live in our bodies and help us digest food; they also create oxygen, helping us breathe. Bacteria and fungi are types of microbes; some scientists also call viruses microbes, although others don’t think a virus is alive.
Single-cell organisms probably ruled the planet for nearly 3 billion years until multicellular life was born roughly 1 billion years ago. The first simple animal probably evolved about 600 million years ago, followed closely (by 30 million years, a paltry span in evolutionary terms) by arthropods like insects and crustaceans. Fish were born 500 million years ago, and mammals about 200 million years ago. Our own genus of homo is still a baby at 2.5 million years old.
Humans Didn’t Evolve from Apes or Monkeys
We didn’t evolve from monkeys. But evidence shows that we do share a common ancestor that split into two different lineages: ape and human. An assortment of early humans, like Australopithecus, Homo erectus and Homo floresiensis, came and went, while our familiar species of homo sapien burst onto the scene a mere 200,000 years before today.
We have a lot of work to do in completing the evolutionary charts, and doubtless new species will reveal themselves while others are disproven. However, we know far more about our roots that at any other time in history, and that’s a beautiful thing. Someday, we may even relate to plants as we do animals—after all, our DNA is 60-percent similar to banana trees, according to genetic counselor Sandi Woo of the National Human Genome Research Institute. And plants do have a similar cellular structure to our own, with just a few differences like rigid cell walls.
Of all the “maybes” that circle evolution, scientists do agree on one thing: humans are not god-like beings perched at the top of some imagined evolutionary ladder. That species-centric view of a glorified person (a man, usually) atop a pyramid of “lesser beings” who only existed to prop up humankind has long been shattered. Evolution is more like a tree with many branches; countless other species’ evolution coincided with our own, and each “improved” in their own way.
Let’s keep learning, and let our mindsets and actions evolve along with our bodies.
image: Tambako the Jaguar