Why do organisms sometimes have to compete for resources?

Organisms compete not only with Organisms of the same species but also with other Organisms of other species. There is never enough food or space to support all the organisms in a given environment. The organisms have to compete for the resources needed to survive and reproduce.

This is one of the tenets of Darwinian Evolution.

Organisms that are not able to successful complete god extinct. The history of life seems to be the story of extinctions.

It is clear that organisms compete and those that are not able to compete go extinct. It is not clear that the competition causes the creation of new information and the creation of new forms of life.

Even if there is a large amount of food, competition is observed. For example in a water ditch, when algae have enough food, more algae will form in a short amount of time. This results in a lot of algae and then the amount of food is not sufficient anymore to feed all the algae and many will die. This is called eutrophication.

Because resources like food, water, shelter, and partners are scarce in the environment and because there are frequently more organisms than there are resources to support them, organisms may have to compete with one another for available resources.