Bilateral Symmetry in Embryos and SupermodelsScience
Bilateral symmetry in an organism means that one half is roughly a mirror image of the other half. The plane of symmetry is the sagittal plane (vertically through the head and body, with one of each sense organ and limb pair on either side). It’s not a perfect match but it’s remarkably close. This symmetry extends to the cellular level. In fact, most animals are bilaterally symmetric, including humans. The oldest known bilateral animal is Vernanimalcula from the Ediacaran deposits.
You probably know that beauty has something to do with facial symmetry. Maybe you’ve even heard of the Fibonacci sequence or something or other. So, why is beauty linked to symmetry? Well, take a look at how the human face is formed…
Now you know what the philtrum is. All of this development happens during a critical time in our life. So many things can go wrong at this phase of embryo development. Getting this bit right means that the rest of you is mostly likely in good working order. A failure of symmetry at this phase in development will likely also mean a range of other abnormalities that are not as visible. Or in evolutionary terms, you actually can judge a book by its cover. Like any great supermodel, evolution can be a perfectly symmetrical bitch.
Learn more about Facial Morphogenesis.