Thermodynamics shows you can't go from a single cell to something more complicated? How do you figure that?
Thermodynamics says to reverse entropy one must add energy. The universe is entropic, it wants to achieve the lowest possible energy state which means things literally disintegrate or vibrate themselves apart if left alone in a perfect vacuum. The complex DNA molecule must reverse entropy to self assemble which means energy came from some where to jump start the process. Most people start throwing out cosmic rays and lightning bolts to get around the thermodynamics argument, but it only makes the probability (which is 0 to begin with as mathematicians define 10E-50 or smaller to be considered 0 in probability cases) of the self assembly of the DNA molecule occuring even worse. Mathematicians and physicists have went into great detail on this topic, I encourage you to go read up on it.