Cellular levels of organization, is the hierarchy of complex biological structures and systems that define life. The traditional hierarchy, as detailed in the picture, extends from atoms to biospheres. Each level in the hierarchy represents an increase in organizational complexity, with each "object" being primarily composed of the previous level's basic unit. The basic principle behind the organization is the concept of emergence—the properties and functions found at a hierarchical level are not present and irrelevant at the lower levels.

 

• The A-Cellular or the Pre-cellular level starts with Atom. It is the smallest unit of matter. Multiple atoms of same type or different type join to form the Molecules.

 

• The Sub-Cellular Level comprises of the Organelles, a functional group of specific molecules or macromolecules.

 

• The Cellular Level consists of the Cells - the basic unit of life formed by grouping multiple organelles to perform different functions.

 

• The Super-Cellular Level starts with the the functional grouping of cells known as a Tissue. Multiple tissues together form an Organ which in turn group with other organs to form an Organ System. An Organism is a collection of many such type of organ systems performing various functions required for the organism to survive. A group of organisms of the same species is known as a Population and a group of interacting populations is called a Community. The Ecosystem is a grouping of organisms from all biological domains in conjunction with the physical environment. And finally the Biosphere is all forms of life on our planet earth plus the physical environment.