Metaphorically speaking, the whole story is basically in the book to demonstrate the human desire for knowledge over all other things, the other stuff in there is just to distract people. Dig for the understanding of the words, not for the meaning. In essence everything in the first part of the bible is there to describe a certain value, not necessarily to tell a story, because quite frankly, 99% of the story's are far-fetched.
The book was written by people, remember that, PEOPLE. And many other people look to the book as fact rather than a clever way to indirectly give wisdom to people who do not have wisdom.
Richard