Ecosystem has a large number of individual organisms which belong to many different species. A population is defined as that assemblage representing the total number of individuals of a single species in a specified area. The member of birch, of maple trees in a forest constitute the population. All the different populations in a forest would be called a community.
The plant or animal community has a population in which the most prevalent species are those that are in abundance, and the very rare and extremely common species are fewer in number. The graph that shows the population distribution in a system is called