Human evolution is one of the most debated and sometimes controversial topics on the planet. Some people feel that all the animals and plants appeared simultaneously on Earth, while the scientific community pushes back explaining the long and complex process of natural selection and evolution.
It has always been somewhat of a mystery to explain how we got from humble beginnings as a single celled organism to the highly complex and dominant force on the planet that we are today. Recently, scientists discovered what they believe could help fill in the mystery and help us explain exactly how we got to where we are today.
I am he as you are he
Who are we? How did we get to be here? How did we come to be the way we are? With our hands, our thumbs, our brain. The ability to walk upright on two legs, to free up our hands to do a whole host of other tasks. We can write, draw, build, and create. The world is at our fingertips.
Strength in thumbs
We are the only species on the planet like us, and while there are some that are similar we, in our uniqueness have become dominant. To really explain the story and get to the part where we talk about us, and what we are there are certain things that need to be explained about life.
Book of life
Every living thing in the world is made up of DNA which serves as the instructions to our body telling it what to do. It is the manual of life, an entire book with only 4 letters, A G T C, but how those letters are ordered tell the most diverse and complex story ever written.
It’s a long book
If you were to lay out all the words in our story it would take up roughly 262000 pages, but of those only about 500 pages would be truly ours. We share so much of our story with every other living thing on the plant. Between other humans, 99.9% of our genetic code is shared.
We are all one
But that should make sense right? At the end of the day, how different should two randomly chosen people really be? Maybe you have a different hair, eye, or skin color but, aside from a genetic error, that really is the only difference we have between each other and even those errors fit within the 0.1%.
Maybe that’s a chapter
What about to everything else, how different is the 500 pages in the 262000 page book? Well, if you look at our closest living relatives, the chimpanzee, we are 96% the same genetically. Humans and chimpanzees didn’t diverge from each other all that long ago. In fact in terms of the history of Earth, it would have been only the blink of an eye.
The relationship people have with some other species in our connected genetic tree is mind-blowing. Take a cat for instance, 90% of our genes are shared with everyones favorite antisocial roommate that still somehow is probably a better roommate that most people we know.
Part Breakfast Staple
As an aside, humans and cows are only 80% different, and even more fascinating is the link between a human and a banana. Genetically speaking a banana and a human are 60% identical, which could potentially make breakfast a very odd twist on spending time with long lost distant family a few thousand times removed.
Scientists have long known that every living organism on the planet came from some long lost distant ancestor. A simple single-celled proto organism, which we can only guess what it looked like, having no record that survived the rigors of early life on earth and the ever-changing climate.
First Printing Press
As time went on, that early organism divided and reproduced. Each time unwinding its DNA, reading the pages and making a copy, word for word to give to its prodigy. It is the same thing we do, it is the same thing everything does to grow, reproduce and survive.
Glasses Might Help
But the continual reading and writing isn’t perfect and every so often a mistake is made. An A becomes a T, or a C is read as a G. More often than not, when these reading mistakes are made, the end result is nothing. Nothing happens, the subtle misread changes nothing about the way the cell or the body functions.
Every so often though, that change can start to have a big impact. Early earth was hot, and covered in water and all life began in our oceans, swimming happily in their aquatic world. Slowly though, the sea retreated from the shores and a whole new area was revealed. Some animals were able to take in air through their lungs and take their first steps onto the shore.
The first entry
Those first few breaths and fin steps started everything on land. The apes, the humans, the cats, the birds. Each time a copy error happened something would change, and after millions of years those early land walking and air breathing species slowly morphed into everything we know now. But the question still remained how? It is one thing to say that it happened, now we have to prove it.
We beat everyone
As far as most scientists are concerned the current consensus is that we are the successful lineage between three subspecies of early man, though the exact number isn’t actually known we simply have strong fossil evidence favoring the current standard in understanding our evolution. While some records show other possible paths, we largely believe that they still fit within these overlapping species.
Africa is Home
What we know from today’s scientific records is that the early parts of human civilization started in what is now the middle east, and parts of Africa. This part of the world has become a treasure trove for fossil records and the clues that have been leading us toward our evolutionary pathway.
Previously discovered in Ethiopia was the partial remains of the now famous fossil that has become to be known as Lucy. She was one of the first early examples of the genius Homo which included our early ancestors but existed after our evolutionary pathway diverged from the other great apes.
The First Lady
The fossil records of Lucy place her somewhere around 3.6 million years ago in our evolution. By now we as a species had already learnt to walk on two legs and lived low to the ground unlike chimpanzees and other monkeys. At this point though she wouldn’t have walked exactly like we do quite yet, having slightly different size ratios of bones in the body.
More Ape than Human
Furthermore, her teeth and brain size hadn’t quite adapted to the diet that modern humans exist on currently. It should be noted however that Lucy was only found as a partial fossil and much of the information that we have is from other examples of the same species. From these sets we have a fairly detailed dental record and it has been noted that Lucy was likely not much of a carnivore having small canines and incisors which likely related to her smaller brain size and height when compared to today.
New Puzzle Piece
Very recently a fragment of a new fossil was discovered in Ethiopia as well. A piece of a jaw in the Ledi region of the country was unearthed as part of an excavation by a team of archeologists. The recovered jaw was dated to be around 2.8 million years old placing the species this belonged to somewhere between the 3.8 million-year-old Lucy and us humans today. But well after the proposed 8-million-year-old species that both Humans and Chimps share.
Back to the begining
The Ledi jaw is a remarkable discovery toward the human evolutionary tree. The teeth of this early ancestor resemble that of modern humans rather than our fruit eating ape cousins suggesting that this species altered its diet since the time of Lucy, likely as a result of the desert climate it was living in. However the chin of the jaw sloped backwards like that of a gorilla suggesting that there are still other species that will fill in the gaps.
Judging by the shape of the jaw fragment the 2.8 million year old jaw is expected to fit between Homo sapien and Homo habilis, which is the closest ancestor that we currently are aware of with fossil records dating back to 1.8 million years old. Using advanced 3-D modeling from the fossil fragments we know that H. habilis, had similar finger dexterity to ours and was able to use tools.
This current jaw fragment has spurred on continued excavations in the area, while more pieces of the jaws’ owner are being hunted. Scientists have yet to formally name it or find its exact place on the evolutionary tree until more pieces are found. However they are quick to state that the evolutionary tree of humans is deep and more complicated than perhaps many had originally anticipated.