Evolution of Human Bone Structure

“Another factor that played a massive role in the path of human evolution is the brain size. One of modern day human’s defining features is our brain to body size ratio.”

The Evolution of Human Bone Structure Evolution of Human Bone Structure By Henry Smith An representation of human evolution over time (fig 1)

Evolution is a crucial piece in the puzzle of our past, it gives an explanation as to why so many creatures have similar features, like lungs, or livers. An important part of the whole idea of evolution, is the evolution of us, humans. Humans did not simply change from a prehistoric ape to a human, they evolved slowly, and over many generations, and species. This long evolutionary process results in what is here today, homo sapiens.

Over the years humans have changed a lot (see fig 1) but what changed on the inside. An important characteristic of modern day humans is our ability to walk on two legs. About 10 million years ago, an ape, Rudapithecus hungaricus, developed a flexible and long lower back, which may have allowed it to walk on two legs (Barras). This ape may have been the predecessor to all bipedal apes and humans.

An image of an 8-9 year old Homo erectus male (fig 2)

Humans have also evolved with the climate, and environment around us. For example, Homo erectus (see fig 2) was very tall, this was because it was easier for them to shed heat. They also had very slender bodies which also allowed them to better shed heat (Smithsonian’s National Museum of Natural History). Another example of an ancestor who adapted to its climate is Homo neanderthalensis. Homo neanderthalensis was much shorter than Homo erectus standing at only 5” 4 or 1.63 meters on average (Smithsonian’s National Museum of Natural History). This is a comparison to Homo erectus that stands on average at 6” (1.85 meters).

Another factor that played a massive role in the path of human evolution is the brain size. One of modern day humans defining features is our brain to body size ratio. How did humans acquire this unusually large brain, over years and years of evolution (see fig 3). As you can see in figure 3, the more time that passes, the bigger the brain size becomes in our ancestors. For example, Homo erectus has a brain size of 900 cc while Homo sapiens has an average size of 1400 cc (The Physical Characteristics Of Humans).

A chart that shows the human brain size vs time (fig 3)

The last thing that has drastically changed in humans evolution is our jaw structure and our teeth. If you look at modern day humans, they

generally have much smaller teeth and much less robust jaws (UCL). For example Neanderthals from 30,000 years ago, have much bigger incisor (the four front teeth in humans), and canines (the 2 teeth on either side of the incisors) (UCL) (Watson). Another interesting thing that we see when looking at ancient human teeth is that the wear on the teeth is much higher (UCL). Archeologist have found evidence of this in ancient human hunters and gatherers like the Inuit and Australian aborigine people (UCL). The archeologist also noted that they found evidence that many middle-aged ancient humans, had their teeth already worn down to the roots (UCL). Things like this very uncommon in modern day dentistry and goes to show how different ancient humans were to us (UCL).

Overall the change in humans through the course of evolution has been drastic, humans have adapted to be taller and shorter depending on the climate. Humans have also had massive improvements in the size of our brains.

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