system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Given that life has existed far longer in our oceans than on land, why hasn't there been species that evolved with the same intelligence level has higher primates?

An earlier question concluded that dolphins are an example of an aquatic intelligent species and yet humans have been far more successful. This also doesn't account for the fact that life existed in our oceans far, far longer than it has on land.

Basically, I want to know why we aren't having epic battles with mermen for rule over Earth.
gpt
Evolution doesn't have a specific goal.

It isn't like "Human Level Intelligence" is the goal that everything is working towards.

Everything adapts in such a way as to be specialized for the environment in which it lives; those which are better adapted to the environment tend to live, while those which are less adapted tend to die.

Humans became so intelligent because of a couple of specific mutations in specific genes; one of the big ones was in a gene that codes for our jaw strength, oddly enough.

That gene ALSO codes for brain size; so as our jaws grew weaker, our brains grew larger and more complex, and the increased intelligence gave a greater adaptability to our environment than the reduced jaw size removed.