If you haven't already, you might be interested to read some of Lynn Margulis' work. She was a big proponent of the idea that symbiosis is an overlooked source

If you haven't already, you might be interested to read some of Lynn Margulis' work. She was a big proponent of the idea that symbiosis is an overlooked source of speciation. In a book of hers I read recently she emphasized how complex organisms like humans depend on a huge foundation of other simpler organisms. You might find some interesting fuel for your ideas in her books.