The Median Artery

At the University of Adelaide, in Australia, researchers have recently found that in the last two centuries, as many as one in three people have a median artery in their forearm. Usually, this artery disappears in the womb during development, replaced by the radial and ulnar arteries to supply the hand and fingers with blood. Less than three hundred years ago, only ten percent of the population had the median artery. From an evolutionary point of view, this is a fairly significant increase in a very short period of time. In fact, if it continues at this rate, by 2100 it is expected that 100% of the population will have the median artery in their forearm. (1)

Evolution: The Never Ending Story

We know that evolution is seen as a change in species over time thanks to Charles Darwin, who formalized the idea in his seminal book, On the Origin of Species – highlighting the concepts of natural selection and adaptation as key components to a species’ future. (2)

Natural selection is the way in which an organism adapts to its environment through selective reproducing. But Darwin says that evolution is slow, incremental, and occurs over thousands of years. So exactly what the purpose of the median artery is, or why it is developing so quickly remains to be seen. Maybe it has to do with an increase in use our hands are getting, and the need for more nutrients and oxygen to be circulated through the hands and fingers, especially since the introduction of the computer.

But an extra artery in the forearm isn’t the only way that humans are still evolving. For example, while modern healthcare has kept many of us healthy and alive, those people living in countries without access to modern medicine are continuing to evolve. Recent DNA tests show evidence of genetic resistance to killer diseases like malaria and Lassa fever. (3)

There are several other examples of human anatomy changing over time, include the pervasiveness of spina bifida occulta (opening of the sacral canal), abnormal connections of two or more bones in feet, increasing absence of wisdom teeth, thyroidea ima artery (branch of the aortic arch)—decreased over time, disappeared completely by the end of the 20th century) and fabella (small bone in the back of the knee joint—increased over time). (4) 

Environment and Adaptation

Human evolution is also related to environmental conditions. In fact, in populations that live in higher altitudes, a genetic mutation has been found. It increases blood oxygen content so that these people have a better advantage of survival in places like Tibet, Ethiopia, and the Andes. (3)

Diet is another area of adaptation. A look at the Inuit DNA shows that there is an adaptation that allows them to survive on a fat-rich diet of Arctic animals. (3)

Looking Ahead

There is a lot to explore in the field of evolution. Not just in terms of where we came from, but in how we approach problems in the future. Understanding evolution and evolutionary research can provide some important insights into the treatment and prevention of diseases. It can also create a better understanding of why certain populations are more adaptable to external factors than others. (4)