Sunday, March 11, 2012

Comparison between unicellular and multicellular organisms


Unicellular organism
Multicellular organism
1.        Body is made up of single cell
Body is made up of numerous cells
2.        Division of labour is at the organelle level. It gives a low level of operational efficiency
Division of labour may be at cellular, tissue, organ and organ system level. It gives high degree of operational efficiency
3.        A single cell carries out all the life processes
Different cells are specialized to perform different functions
4.        The cell body is exposed to the environment on all sides
Only outer cells are specialized to face the environment. Inner cells are devoted to other functions
5.        An injury of the cells can cause death of the organism.
Injury or death of some cells does not affect the organisms as the same can be replaced by new one.
6.        A cell body cannot attain a large size because of the limit imposed by surface area to volume ratio
A multicellular body can attain a large size increasing the number of small cells
7.        Lifespan is short due to heavy load of work
Lifespan is long due to limited load of work for each cell type
8.        Power of division is not lost
Certain specialized cells lose power of division
9.        A well-marked capacity of regeneration is present
The capacity of regeneration decreases with increasing specialization
10.      The cell has the same role for itself and the organism
Cells have a double role. One for themselves and other for the organism


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