In its most literal sense, the term "environment" refers to "surroundings" (environs). An individual's, object's, element's, or system's environment includes all other things with whom it interacts. Individuals, things, elements, and systems rarely exist in isolation; instead, they interact with their environment to varying degrees.
The environment, therefore, encompasses everything that surrounds or affects an organism during the course of its life. The term "environment" refers to an organism's "totality of living and non-living components, their effects and occurrences."
All species are fully dependent on other organisms and their environs for food, energy, water, oxygen, shelter, and other essentials. The relationship and connection between organism and environment are highly complex. It is composed of both biotic and abiotic (non-living) components.
Abiotic Components: These are the inorganic or non-living parts of the world. It consists of soil, water, air, light energy, chemicals and elements (oxygen, nitrogen etc) and physical processes such as volcanic eruptions, earthquakes. forest fires among others.
They are the most important determinants of where and how well an organism exists in its environment. Biotic Components: Biotic components includes living organisms such as plants, animals and microbes which are further classified based on their functional attributes as producers or consumers. They can be further divided into : Autotrophs, Heterotrophs, Macro Consumers, Micro Consumers etc.
The environment is in constant flux. Both biotic and abiotic elements are dynamic and constantly changing.
External environment of organisms
The external environment is the habitat of an organism and is composed of both biotic and abiotic components.
The abiotic components include light and temperature, as well as water that contains nutrients, oxygen, other gases, and organic matter. The biotic components include microorganisms (plankton), as well as aquatic plants and animals, as well as decomposers.
Internal environment of the organism
The internal environment is entirely encased by the exterior body surface of the organism. Essentially anything that lies within the defined body of an organism is its internal environment. The internal environment is relatively steady in comparison to the external environment. Nevertheless, this is not always the case. Internal environment disruptions occur as a result of injury, sickness, or acute stress. For instance, if a marine fish is transplanted into a freshwater environment, It will perish.