What are the factors that affect population growth and size?

Population growth and size are fundamentally influenced by limiting factors, which are the environmental conditions and resources that restrict the growth of a population. These factors can include availability of food, water, habitat space, and essential resources, as well as the presence of predators, disease, and competition among species. When these limiting factors are favorable, populations may grow quickly, but when they are scarce or adverse conditions prevail, they can limit population growth or even lead to a decline in size.

While energy resources and technology, cities and infrastructure, and migration patterns can play roles in shaping population dynamics, they do not directly establish the constraints on population growth in the same fundamental way that limiting factors do. Understanding limiting factors is crucial for ecology and conservation, as they directly impact an ecosystem's ability to sustain its population levels.