Well, now that someone has been kind enough to bring up this issue, let's talk about it. You'll be happy to know that we're in my wheelhouse with this statement. I've taken three courses called "Thermodynamics," a fourth that should have also been explicitly called 'Thermodynamics,' and probably over a dozen others that discussed thermodynamic concepts in painstaking detail. I am chemical engineer, hear me roar! Thermo-woo pushers, beware!
Thermo 101
The Second Law of Thermodynamics is a tough cookie; my professors didn't spend all that time lecturing about it for their health. The first law is the conservation of energy and the third law defines absolute zero; neither of these is too tricky either conceptually or practically. You can't just create or destroy energy willy-nilly, and things can only get so cold before you bottom out on the temperature scale.
The second law can't be summed up as easily as its buddies. It can be expressed or explained in a variety of ways, ranging from the abstract (dQ = TdS) to the humorous (the 1st, 2nd, and 3rd laws say "you can't win, you must lose, and you can't leave the table"). Most hard science classes stick with the abstract, either dQ = TdS or S = k*ln(omega), probably because trying to wrap your mind around abstract concepts like entropy (S) can make your brain ache. For instance, you can use the second law to show that the rate of change in entropy with respect to volume at constant temperature equals the rate of change in pressure with respect to temperature at constant volume. Chew on that for awhile. Actually, don't ... it's inherently non-intuitive and abstract.
So what does the second law say, at least colloquially? It says that entropy must increase in an isolated system. And what is entropy? In a word, it's randomness. Thus, the randomness in an isolated system must increase any time something happens. To steal the stereotypical example from high school chemistry teachers around the world, think about an egg breaking. If you drop an egg, it will break and splatter yolk all over the floor. But, you never see a busted egg's entropy increase by spontaneously reassembling into a whole egg. This isn't the entire story, of course, but it's enough to get by on for this week's statement.
You Down Wit Entropy? (Yeah You Know Me!)
Holy crap, does that mean the people spouting this week's statement are right? Much of evolution decreases randomness by increasing complexity. The large animals walking around today are much less random than the simple unicellular organisms that dominated early life, according to the theory of evolution. But, the second law says that entropy must increase with time. Is this an intractable problem? How do we sort this out?
Let's ask MC Hawking, physicist Stephen Hawking's gangsta rapping alter-ego:
Creationists always try to use the second law
To disprove evolution, but their theory has a flaw.
The second law is quite precise about where it applies,
Only in a closed system must the entropy count rise.
The earth's not a closed system; it's powered by the sun,
So f--- the damn creationists, Doomsday get my gun!
"Entropy", A Brief History of Rhyme: MC Hawking's Greatest Hits
Bingo. Entropy must rise in an isolated system, meaning a system that doesn't exchange heat or mass with its surroundings. The earth and the rest of the universe exchange tons of mass and heat, so the earth's entropy doesn't have to increase with time. So long as the universe's entropy is always going up, the second law isn't violated.
Let's try applying this logic to something besides evolution. By this argument, we could never make ice cubes. Freezing is a serious loss in entropy; the water molecules go from freely and randomly floating around in the ice cube tray to being rigidly locked in a big ice crystal. The trick is that the heat leaving the ice cube tray goes elsewhere (mostly behind the fridge) and increases that place's entropy. The second law states that the entropy gained by the heated air behind the refrigerator will be greater than the entropy lost by the water molecules frozen into the ice cube. Thus, the entropy in the fairly isolated system of fridge-plus-surrounding-air has increased, and so the thermo gods are satisfied. (They're free to go back to fighting Maxwell's demon.)
Nice Try, Evolution Deniers
This statement amounts to either: a little bit of knowledge being dangerous (since the bit about isolated systems is a fine point), or another example of true believers starting with their conclusion (evolution didn't happen) and hunting for anomalies. Decide for yourself which of those possibilities is more likely; I divulged my opinion on the matter in bold above. Unfortunately for any evolution deniers trying to use this argument, the anomaly isn't even there this time.