Wednesday, December 21, 2011

Study reveals how evolution shaped the human skull

The most remarkable feature of humans are their brains. These peculiar animals have developed such complex brains that they are aware of their own existence, and have an unparalleled ability to shape the world around them. It leads to all kinds of sensational technology, or even being able to write this blogpost. In a large study of skeletons, scientist revealed how the shell that surrounds the brain, our skull, has evolved over time, shedding light on how we became who we are.

Skull study
Scientists from the universities of Manchester and Barcelona investigated skull shapes in a large collection found in a Catholic church in Austria. The church, located in Hallstatt, has the peculiar habit of collecting skulls of the deceased after their graves have been dug up to make room for others. The large collection of skulls allowed the researchers to study their shape, and derive evolutionary changes from them. They found that the human skull is tightly integrated: changing the shape of one part means that other parts are likely to be affected as well.

Changes in the genetic code found in the investigated skulls revealed how changes in one part could lead to changes in other parts. If evolution favours a genetic variation in a specific part of the brain, other areas are likely to respond with changes as well. Because changes in genetic code are the basis for evolution, scientists were able to map how the shape of our skull has evolved. They showed that computer models based on their findings were able to predict how our skull was shaped during evolution

Brain size
Human brains have unparalleled capabilities in the animal kingdom, but this is not necessarily because our brains are bigger. The shape of the brain plays a much larger role. That is also why skull shape is important: it tells us something about how our most discerning characteristic came to be, as the skull is meant to hold the complex set of wires that form our brain. Because size does not matter, shape likely does.

Human evolution
The evolution of the Homo sapiens, the species everyone that can read this belongs to, goes back millions of years. We came to be in large extent to evolution of the Australopithecus, a human-like animal that lived between 4 and 2 million years ago. It gave evolutionary birth to the genus Homo, that we all belong to. While several species belonged to it, they are now all extinct, except for us. Our closest relatives are Homo neanderthalensis, which became extinct only 30,000 years ago.

How long will it take before Homo sapiens will become extinct? And maybe more importantly, what will cause it?

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