Another reason might be that the human species evolved in the water.
Figure out how many new species evolved in that time.
We are used to the idea that species evolve because of changes in their natural environment.
There is evidence enough that your species evolved on Earth.
The first intelligent species should have evolved seven to ten billion years ago.
No one can be quite sure, of course, what has caused the two species to evolve in slightly different ways.
He doubts if the human species could have evolved without them.
My theory is that our species evolved in a dangerous environment.
But as the years and generations passed, different species evolved in separate ways.
Such thinking can lead on to the idea that species evolve because they "need to" in order to adapt to environmental changes.
