Why Do Only Humans Have Beards? Scientists Discover They Might Not Serve Any Purpose
Evolutionary biologists have long debated the reason why Homo sapiens evolved with a prominent chin, but this unique characteristic may be a byproduct of other traits shaped by natural selection.
TL;DR
- The human chin, a unique characteristic among primates, may not have evolved for a specific purpose.
- A new study proposes that the chin is a byproduct of upright posture, larger brains, and changes in diet.
- As ancestors became more upright, skulls bent, and faces retracted, while reduced need for large teeth and chewing muscles further altered the jaw.
- These combined changes left the lower jaw projecting beyond the teeth, resulting in the chin.
- The study highlights how selection for one trait can have consequential effects on other parts of the body, a concept known as an evolutionary byproduct or 'spandrel'.