How do factors such as food, water, shelter, and space affect populations in an ecosystem?

All of the factors listed above, except food can be classified as abiotic factors. Food (the presence of plants,animals and other organisms in the ecosystem and their complex relationships) is the biotic component of the ecosystem.
These factors affect the distribution, survival and  genetic characteristics of the populations. The lack of water, shelter and space can prevent certain species from living in the ecosystem or cause strong pressure of the natural selection and shape the genetic structure of the population.
Complex biotic relationship also influence behavior, presence and genetic structure of the populations.