https://www.youtube.com/watch?v=ORmciWDIm7M
I am hung-up on biofilm. It is a massing of bacteria
into the beginning of a primitive sponge-like
multicellular organism--an evolutionary transition.
The biofilms I find in my cultures look like accretions
of the remains of organisms and other components of the
microcosm stuck in a trap of mucous-like membrane.
This is a gently conducted tour. Take a look.