Biology: Levels of Organization
Organization is the arrangement of smaller components of ana structure, system, or situation into larger ones and larger ones into still larger ones in a hierarchy, where components of each level coordinate with one another towards a common goal. It is a sort of hierarchy or pyramid of levels where each level is made of components of the lower level and itself becomes a component of the higher level.
1. Atomic level
The basic unit or component of organization in both living and non-living object is an atom. An atom is, of course further made of still smaller particles like electrons, protons and neutrons.
2. Molecular level
Atoms combine with one another to form molecules Examples are:
pure water ( H2O)
sodium chloride ( NaCl – also called table salt)
glucose ( C6H12O6)
proteins
carbohydrates
lipids
Macromolecules are large, biologically important molecules inside cells.
3. Cellular Level
The subcellular components coordinate their activities to produce living cells. Living beings are made of one cell (unicellular organisms) or numerous cells (multicellular organisms). Unicellular organisms are more appropriately called acellular organisms.
They are the most abundant of all the living creatures. Unicellular or acellular organisms possess protoplasmic organisation. Multicellular organisms have higher levels of organization like cellular organization (sponges), tissue organization (coelenterates),organ organization and organ system organization.
4. Tissue Level
In multicellular organisms the cells may be similar (colonial organisms) or organized into distinct functional units called tissue. A tissue is a group of cells with similar structure performing the same function
There are four basic types of tissue found in the human body:
Epithelial
Connective
Muscular
Neural
5. Organ Level
Two or more tissues are organized into distinct structures called organs . Organs are specialized for performing one or more functions e.g. pumping by heart, photosynthesis by leaves.
6. Organ system Level
Two or more organs coordinate their activities towards a common activity e.g. digestive system, respiratory system.
7. Organismic level or Individual level
Living beings are called organisms because they possess high level of organization. They are called individuals as each organism has a distinct interact or individuality.
8. Population level
All the individuals of a species found in an area where they can interact with one another is called population.
9. Community level
The populations of different species found in an area also interact with one another . They constitute a biotic community.
10. Ecosystem Level
The biotic community of an area and its abiotic environment together form an ecosystem.
11. Biosphere level
All the ecosystems of the world interact further and form biosphere or livable space of the earth. An organism is, therefore, not only an individual but also a part of population, community, ecosystem and biosphere.
Biosphere has the highest level of organization. Organizations at level of individual and above are known as higher levels of organisation.
It represents ecological hierarchy. Organizations below the level of individual (organ system, organ, tissue, cell, molecules, atoms ) are called as lower level of organization.
