Jerry Coyne discusses Sean Carroll's interview in the New York Times in his blog, Why Evolution Is True:
Carroll is a smart and amiable guy, and gives a good interview. There’s one place, however, where I think he misses the mark. That’s where he discusses the effect of time’s directionality on biology, specifically ageing:
Q. THE CENTERPIECE OF THE RECENT MOVIE “BENJAMIN BUTTON” AND THE ABC TELEVISION SERIES “FLASH FORWARD” IS THE TIME TRAVEL. HOW DO YOU RATE THE SCIENCE OF THOSE ENTERTAINMENTS?
A. Well, the Benjamin Button character ages in reverse. In “Fast Forward” people glimpse the future. These are great story-telling devices.
But the writers can’t resist the temptation to bend the rules. If time travel were possible, you still wouldn’t be able to change the past — it’s already happened! Benjamin Button, he’s born old and his body grows younger. That can’t be true because being younger is a very specific state of high organization. A body accumulates various failures and signs of age because of the arrow of time.
But I don’t think that entropy (at least in bodies) is the only solution here, or even an important solution, for it’s perfectly possible for a body to be immortal, and some plants (and bdelloid rotifers, who appear to reproduce largely asexually) have approached physical immortality. There’s far more to ageing than just “the arrow of time.” Indeed, the inexorable increase in entropy encapsulated in the second law of thermodynamics, a law that holds over the whole universe, is violated locally by two biological phenomena: development and evolution.
More here. [Sean admits that ageing is too complicated to be explained by entropy alone.]