Life is like a waterwheel that uses the energy of the falling water to pump a little water back up river, temporally snubbing entropy. This is similar to how a ball bounces. The energy is not reversed, only its direction is. Life creates complexity like a slough delays waters trip to the sea. Just as plants are like a waterwheel in the river of sun energy, animals are a waterwheel in the river of plant energy.
Predators are a wheel father removed.
The bacteria in their guts are still more removed, getting the last drops of energy. Geans have been very successful at stumbling upon effective designs because when an improvement increases their resources, they can make that many more copies of themselves. This improves their odds of getting lucky again. Also, genes never forget a trick. Many of the most important ones in our bodies have not changed design in over 3 billion years.