Our ecologists spend much time studying and analyzing how our world changes everyday. There are many different populations that fill up our world up . A population can be defined as a number of same species individuals that live in a certain area. They share similar characteristics and rely on the same resources to survive. The study of how a population interacts with its ecosystem is known as population ecology.Studying population ecologies helps researchers learn how species live, and what species are endangered. population ecology has to do with theoretical model building, it also consists of observations and experiments in the field.