Entropy is a measurement of the amount of energy that is not available to perform work. A system that is closed to external inputs will over time have a depleting amount of energy to perform work–i.e., it will exhibit increasing entropy.
Biological systems on the earth (including humans) happen to have an external source of energy with which work can be performed, though. I’m thinking of the Beatles song…
As long as our sun keeps fusing hydrogen into helium, entropy is not a problem for biological systems. AiG indeed acknowledged this very fact on one of their “Arguments to Avoid” pages:
The law [of entropy] allows for increasing the amount of order in a given system, so when applying the law the system being discussed must be carefully defined.