The Easter Island example of unchecked population growth perfectly demonstrates what will happen if there's too much population that uses too much natural resources.
In the Easter Island, the population was growing rapidly, and people living there didn't seemed to think that it will cause problems until it was too late. The big population, on such a small area, with very limited resources, soon turned from heaven to hell, with people starving, being sacrificed to the gods for help, and being totally isolated so that they couldn't get help or even escape because they took down every single tree on the island, so eventually they all died.
This tells us what will happen if the population in the world continues to grow rapidly, and if e continue to destroy the environment, that we will end up with nothing that can support our lives on the destroyed planet, and that it will all end terribly.
