Subject: How did very small organisms ever survive browning movement to begin with?

I have observed the effects of browning movement on smoke particels using a 
fairly low powered microscope and the particels are being knocked about quite 
violently.  Life on earth supposidly begain with small organisims that 
developed into more complex larger ones.  It seems so unlikely in some ways 
because of the effects of the violent bombardment of molecular motion on such 
small organisms.  For a bacterium or a virus being so small the constant 
assualt must be quite severe and I don't understand how they could survive much 
less evolve to start with.  Can anyone clear this up for me?
I appreciate your time and value your answers.
Milton

Re: How did very small organisms ever survive browning movement to begin with?