Why should we think that random mutation accounted for all of the developments in life? Because when the mutations are favorable, in one way or another, they are selected for, when they are not favorable, they are usually disastrous, they are selected against. "Favorable", at the stage of complex life, say from the the amoeba on up, means more likely to survive to reproduce, or just more likely to reproduce.
Pretty much the same at lower levels, except that the concept of "reproduce" becomes more chemical or biochemical than biological. But the principal is the same.
This guy's version of the first and seconds laws of thermodynamics are not the ones I was taught in an Engineering Thermodynamics. And not just taught in the sense of memorizing something, but of understanding. Don't think I could reproduce the logic here, it has been 35 or so years ago, and it's not an area I work in.
Combined Law of Thermodynamics
For energy E, temperature T, Entropy S, pressure P, and volume V, (The little 'd' stands for delta or change in)
However, people decrease entropy all the time, an air conditioner does it, but always at the expense of doing work (using energy) and increasing entropy in the larger system.
Why should we think that random mutation accounted for all of the developments in life? One answer, from a naturalistic perspective, is something like this: 1. The mutations that led to speciation were either directed by intelligence, or they happened randomly. 2. It's outside the realm of science to consider the existence of some intelligence that manipulates the mutation of organisms. 3. Therefore, from a scientific point of view, the mutations in question must have happened randomly.
This line of reasoning, of course, has holes in it you could fly a C-5 through. The first of these is that point 1 is a false dichotomy; just because a process happens naturally, without exterior guidance, emphatically does not mean that the process is random. A large subset of science is devoted to the derivation of mathematical formulae that describe the operation of the universe, and there's no reason to believe that speciation doesn't operate according to its own attendant formulae.
I didn't go through this exercise to construct a straw man, however. I just mean to point out what I see may be inarticulated assumptions in the common naturalistic point of view.