ecology is the study of living populations of both as individual members and as entire species in relation to their surroundings; both their organic and inorganic conditions of existence.
The specimen is seen in the entire context of its surroundings, its predator and prey relationships and the vicissitudes of its life-cycle; its complete milieu.
As a synthetic and analytical science, ecology describes relations among 
living creatures in an attempt to predict the impact of measurable internal and external changes on the species, populations, or individuals in question.
The connections among immediate, proximate, and distant influences can be too tenuous, so that ecological studies emphasize measurable and observed patterns on scales ranging from physically small and molecular scales to regional flora and fauna comprising landscapes, watersheds and entire water bodies. How the population alters its existence is as crucial to comprehend as the impact that a changing environment has on the population, its members and related species.
The angel fish and the anemone are symbols of precisely how intimate two genetically separate species can become under conditions which secure their common survival.
