Level of biological organization article for 9th class,10th class,school and college sindh board aku board notes free

Living organisms are highly complex and organized.This complexity and organization is composed of grading of structures with each level based on the one below it, and providing the foundation for one above it.Life is built on a chemical foundation.This foundation is based on elements, each of which is a unique kind of matter.As we know , an Atom is the smallest possible unit of an element, which retains all the properties of that element.Further division of this unit produces isolated subatomic particles of which an atom is composed.Atoms may combine in specific ways to form molecules.

⇨⇨⇨Simple molecules are formed spontaneously, for example, carbon dioxide.Extremely large and complex molecules are manufactured by living matter(within the bodies of living organisms).The molecules of living matter are mostly based on carbon and provide building blocks of living matter.These are called organic molecules.Molecules of different elements comprise a compound.Along with organic compound, inorganic compounds are also associated with living organisms, for example, human blood.

                   

⇨⇨⇨The simple organic molecules are sugar,glycerol,fatty acids,amino acid,purines and pyrimidines.In the bodies of living organisms simple organic molecules are converted into more complex organic molecules.They are recognized as the three categories of food natural macro 

molecules and are required by living organisms.These are carbohydrates,lipids and proteins.

⇨⇨⇨⇨With different chemical arrangement and formation of complex molecules,the life emerges on the level of a cell.Like an atom is the smallest unit of matter,a cell is the basic unit of life.Fundamentally,all cells contain genes, which are functional units of DNA.The genes provides necessary information needed to control the life of cell.The sub-cellular structure, called organelles, function as chemical factories and use the information in the genes to keep the cell alive.A thin covering called cell membrane encloses the cytoplasm along with its inclusion.Some organisms, mostly microscopic, consist of one cell, but larger organisms are composed of many cells.

In these multi-cellular organisms, cells of similar type form tissues, which perform a particular function, for example nervous tissues,connective tissues,xylem tissues etc.Various tissue types combine to make up an organ, for example the heart.Several organs that collectively perform a single function from an organ system, for example together, the brain, spinal code,sense organs, and nerves form the nervous system.Altogether, different organs system functioning in a highly advanced co-ordination and co-operation. 

⇨⇨⇨⇨operation make up an individual whole organism.

Beyond living organisms are broader levels of organization.A group of very similar interbreeding organisms constitutes a species.Members of the same species living in close association in a given area are considered a population.

⇨⇨⇨⇨⇨Populations of several species living and interacting in the same area form a community.A community with it's environment, including land, water and atmosphere, constitute an ecosystem.Finally, the entire surface region of the earth inhabited by living things is called biosphere.