Humans and mammals have an ancient fish mother who came out of the sea to walk on land and give distant birth to us all. We are still closely related to fish. We are eighty percent water and need to constantly drink to survive. Carrying around so much water and being full of blood and being an easily popped water balloon is an extremely inefficient form of life but instead of being more for living on land we inherited our basic life structure from the fish mother. Our hands are modified flippers. Our legs are modified fish tails. The fish mother first turned into some kind of amphibious thing then to reptiles then to birds and mammals. Vertebrates are all very similar and the blood we all share is close to the salinity of the sea. Throughout our millennia of evolution our bodies never forgot the fish mother as we have continued to carry her through our genetic code.