What was Darwin's theory of the struggle of existence?

Darwin's theory of the struggle for existence posits that organisms compete for limited resources such as food, water, and shelter in their environment. This competition leads to a natural selection process, where individuals with advantageous traits are more likely to survive and reproduce. Over time, this results in the adaptation of species to their environments and the evolution of new species. Essentially, the struggle for existence highlights the pressures that drive evolutionary change.