I've got a theory; a very long time ago in a universe of (virtually) nothing but water there existed some fish; eels to be specific. With all of time having passed they reached the pinnacle of evolution. With hands and claws for grasping and manipulation they were the image of the mythical dragon. It's a dark cold watery universe but the dragon had a dream of a place of light and warmth. The dragon created an artificial world; a giant ball and filled it with rocks and a gaseous atmosphere and a warm sun.
Eels can come out of the water on to land and hunt prey for months a time. They do things the like climb trees and ambush prey. These fish still contain the DNA for the mythical beast. In Scotland for instance they have to use giant steel bars on their hydro electric power plant dams in order to keep the dragons out.
In a parrelel universe it could have happened.
Or you think that some monkeys climbed down the tree, and started building buildings with rocks, ended up being the current civilization (the current reality).
Both are ridiculous if you think about it, yet either of them are not that strange if you look about it from a phylosophical standpoint.
Thinking that humanity is somehow extremely importand is childish. Humanity is only a temporary experiment of nature and it wont exist forever.