Ear Formation

Dive Deeper
(Image Credit: Science Source)

About six weeks after conception, the outer ear starts as a groove on the neck, just below the mouth. Over the next two weeks, the outer ear migrates to its final position and becomes shell shaped.1 From there, the outer ear forms more folds, reaching its final shape by 18 weeks after conception.2 The ear’s shape helps a person localize sounds; and since every ear shape is slightly different, everyone’s brain has made slightly different connections so that people have trouble telling the direction of sounds that are recorded inside someone else’s ear.3 Oddly enough, the outer ear actually continues to grow for a person’s entire life.4

The ear at three and a half months after conception. (Image Credit: Priests for Life)
Sperm-egg fusion
Sperm-egg fusion