We can all read the creation story and most of us just take it at face value not actually understanding what they are reading primarily because the ancient middle eastern mentality, language and way of thought was completely different from what our Westernized cultures are accustomed to.
In Genesis (abbr. as Gen.) 1:11 we read:"And God said, Let the earth bring forth grass, the herb yielding seed, and the fruit tree yielding fruit after his kind, whose seed is in itself, upon the earth: and it was so."
Okay, so let's just take a second and look here. First notice that God created Light, land, atmosphere, and night before this verse happens. This is good because no vegetation could come from the land without all of these things in balance. This is as true of a statement as I can start with. Science or opinion cannot argue this point and it is crucial to understand what's next.
Now God brings grass, seed & fruit.
Without which no life that is on the earth would exist. Let's just say for example, and only for example, that 3/4's of the animal kind on earth is herbivorous and ¼ of the earth's animal kind is primarily carnivorous. To balance the life cycles of all animals on the earth there are some carnivores to eat the old, weak and sadly young herbivore or carnivore. This is nature controlling population.