Would the extinction of lions affect the world?

Yes, of course it would. The animals that lions eat would flourish in population numbers. The animals that lions eat may even become pests, and the animals that they eat would become endangered. This is because the more the population grows the more they need to eat. The lion is at the top of the food chain. If it becomes extinct, it throws the ecosystem of the area off. It is like a chain effect: without the lion, there really isn't any other predator to keep control of the quantities of animals there are. And that would completely throw off the balance of the world's ecosystems.