Dumb little boomer man

I was reading this question on Reddit the other day, and in case you are a dumb little boomer man who doesn't know how to click links, i will put the question here for you to read:

"Let's say some guys in the future make a dimension where its a just an infinite McDonalds and they just throw 10 million of every animal on Earth in there, how would life evolve there? Would it be a place dominated by invertebrates?".

Why do we need to know this? We don't, but this is an InfoOwls article, and i am not here to teach you something. I am here to give people existential crisises, answer useless questions, and have fun. So that's exactly what i am going to do today.

Evolution explained

In 1959, Charles Darwin's theory of evolution was accepted as scientific fact. Darwin travelled around the world, and he realized that there was a different set of animals in every country. The animals were alike, but they were different in colour, body shape and abilities. Darwin made the theory that animals change based on their environment.

For example: bears got to the North Pole, darker bears got killed because they are easier to spot in the snow (nature is kinda racist ngl), bears with thin fur freezed to death because of the cold. Only lighter bears with thicker fur survive, these bears hold hands or something (idk how babies get born), and all of the bears from that moment on have light thick fur. This process repeats, and eventually, there are only polar bears.

Rules

So, how would animals evolve in an infinite McDonalds? Let's make some rules on how this dimensinon works, first.

1. The McDonalds buildings include both the restaurant, kitchen and offices. It's an entire McDonalds building.
2. Both the exists and entrances lead to another McDonals building.
3. If you break trough the floor or ceiling, it leads to McDonalds. There is no escape.
4. We will ignore the law of relativity. The dimension won't collapse into itself, and gravity moves downwards just like normal. Even if this shouldn't work, it does for the sake of discussion.
5. The McDonalds contains food.
6. There are 10 million of every animal on Earth in this dimension.

Conclusion

Since food spoils, only scavengers will survive. But there is no sunlight, so everything will die eventually. Anticlimactic, isn't it?