Inertia is the property of an object that describes:

Inertia is the property of an object that basically describes its resistance to change its state of motion.

For instance, if an object is still, inertia describes the "attitude" of the object to stay still (a force should be applied in order to move it). Similarly, if an object is moving by uniform motion (with constant speed), inertia refers to the "attitude" of the object to keep its uniform motion (again, a force should be applied to the object in order to change this state of motion).

Entropy is defined as the increase in disorder in a system. This occurs in the food chain because as animals eat food, they supply less energy to the next level of the food chain. What does this mean? Think of a rabbit. The rabbit eats almost all day, everyday. The energy in the grass is in an ordered state but becomes disordered as it goes though the rabbit. This is because the rabbit does things like cellular respiration, and gives off heat (this is wasted energy -- disorder). So out of the total amount of energy that flows through the rabbit only about 10% of this energy goes on to a fox that eats a rabbit due to all of this wasted energy. Cheers!