For we find that among the animals the hunter has changed as little as the hunted. The serval cat is still powerful in pursuit, and the oryx is still swift in flight; both perpetuate the same relation between their species as they did long ago. Human evolution began when the African climate changed to drought: the lakes shrank, the forest thinned out to savannah. And evidently it was fortunate for the forerunner of man that he was not well adapted to these conditions. For the environment exacts a price for the survival of the fittest; it captures them. When animals like Grevy’s zebra were adapted to the dry savannah, it became a trap in time as well as space; they stayed where they were, and much as they were. The most gracefully adapted of all these animals is surely Grant’s gazelle; yet its lovely leap never took it out of the savannah.
We say that an animal has found its niche. Nature produces carnivores by producing an energy resource that is ripe for the taking by something else that can use it as a resource. Lots of zebra eating grasses. These zebra are, for themselves, the ends of the consumption process that moves from sun to grass to zebra.
But these zebra also contain concentrated energy; that is, they are also food. They are food for another organism that may not yet exist. But nature does fill this gap. Other life forms come to fit into the available position to the right of the zebra. Why not produce no new animals? Or why not produce another grass eater, or another vegetarian what doesn’t eat grass? And why isn’t there a consumer of lions?
The logic of Nature is to let economics determine the final array of allowed forms. Each organism fits like a cogwheel enmeshed with all the rest. This is the system in ecosystem.
But the fact remains that the whole system will survive if you remove the topmost predators. A creative creator God would not have created the lion. Only zebras. And if it turns out that plants do feel pain (something it would be very difficult to establish even if we could talk with them), then the creation of animals would also not have happened.
This is a sub-argument of the anti-theist argument from suffering. I am not saying that suffering as such disproves a non-evil creator, but unnecessary suffering does. Lions are not necessary for zebras. There is enough anxiety in having to find plant food.
The fact that carnivores exist, and the fact that “evil” is rewarded by natural selection, is sufficient to infer that this universe is not under the power of a loving parent.