In humans, four nostrils

Such a discovery led monitoring the process of respiration in fish. Fish extract oxygen from water. Most of them have two pairs of nostrils: Front - water inlet and a pair of "exhaust pipes" - for its release.

Question: if humanity is derived from fish, what had become of the second pair?
Answer: in the depths of his head, turned to internal nostrils called choannae - from the Greek "chimneys." They are connected to the throat and are thus a device that allows us to breathe through the nose.

To do this, the internal nostrils need to somehow ensure the return flow through the mouth. Unbelievable but true: recently Chinese and Swedish scientists have found fish called Kenichthys campbelli - fossil monster, whose age is 395 million years - showing the process in its middle stages. Between the front teeth of fish are clearly visible two holes nozdrepodobnyh.

Fish Kenichthys campbelli - direct ancestor of amphibians can breathe on land and in water. One set of nostrils, let her lie on the shallow water and absorb food, while the second was sticking out of the water - almost like a crocodile.

Similar gaps between the teeth can be seen in the early stages of development of a human embryo. When these gaps are not fused, it turns out "cleft palate". This is how one can explain the old big fish just two longstanding mysteries of mankind.

S. Fry, «The Book of General Ignorance»

via factroom.ru