Human Evolutionary Terms
Did you know that humans still carry traces of ancient ancestors in their bodies today? The term "homology" relates to the similarity of a structure based on descent from a shared common ancestor. This differs from "analogous" structures, such as wings in insects and birds. Here are five examples of ancient traits you might be surprised to learn are still seen in humans today.
Firstly, bipedalism was one of our ancestors' greatest steps. Almost every part of our skeleton was affected by the switch from walking on all fours to standing upright. These adaptations include the alignment and size of the foot bones, hip bones, knees, legs, and vertebral column.
In addition to our eyeballs, there are other large holes (known as fenestrae) in our skulls. A single window is found on each side of the human skull, uniting us with our shared common ancestors from over 300 million years ago.
Most mammals, including humans, have five digits in the hand or foot, known as a "pentadactyl limb". This arrangement most likely arose as a practical solution to weight bearing on land.
Interestingly, our dentition harks back to a whopping 439 million years ago. A tooth whorl is a bizarre row of teeth that curls in on itself in a spiral pattern.
So, the next time you wonder how you're related to that annoying relative, think about the homology that unites us with all of our ancestors.
This article is republished from The Conversation under a Creative Commons license. Read the original article.
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