"it's not the same river any more either."
Really ignorant example. And a wrong one, for the water molecules that comprise your river are still 2 parts Hydrogen and 1 part Oxygen.
Water isn't God's tears, or some other mystic BS.
And I hope you never get a staph infection, or you'll learn up close how nature evolves.
Whatever. Your example is no more suited to demonstrating speciation than mine. Bacteria remain bacteria. I predict they always will. Change? Yes. But still bacteria. Takes a lot of faith to think they will, without guidance and over billions of years, develop arms and legs. That's the faith certain schools think our children deserve. They deserve better.