system
Given the following post, respond as if you're commenting on Reddit:
human
From what I understand, we have only discovered a tiny fraction of the species on earth. Is life so diverse that I may have species that are unique to a 10 acre plot of land?

Maybe just wishful thinking on my part, it would be pretty neat if there were species that evolved into something new while on our land. Any type of life... animals, bugs, plants or microorganisms although I have a feeling that last one is an entire world of its own. We live in a rural area in the southern U.S. with a natural creek and I see so many different bugs when I go exploring. The creek only goes about a half mile and I've seen fish in it, I don't even know how they got there.

Please don't laugh at me if it's completely impossible. Help me understand just how "local" our local wildlife is and how likely it is that we have noticeable evolution going on in our own backyard. 

Edit: We've been here since the 1970's and there are constant changes in the types of animals or plants that thrive and dominate here. We never do anything intentionally to influence that.
gpt
You have to consider how we discover species.  So for example we've almost certainly encountered 90% of the mammals on our planet, but we might be at around 20% of insects and 5% of bacteria.  Similarly, we might know about 70% of river-dwelling aquatic organisms and 20% for those in our oceans.

So if you go take a look in a creek in your backyard, chances are slim you'll find a new species, simply because those sorts of environments are well-studied and you're unlikely to have the tools to do better.  On the other hand, if you go out there and take water samples and put the microorganisms through a whole-genome sequencer, you're almost certain to find something new.