What are the differences between multicellular and unicellular?

Basis of differentiation 

Multicellular Organisms

Unicellular Organisms

Definition 

Refer to organisms that are composed of more than one cell

Refer to organisms that are composed of a single cell

Type of body organization 

Complex 

Simple 

Presence of cell differentiation

Cell differentiation is present

Cell differentiation is absent

Shape

Have a definite shape

Have irregular shapes

Exposure to environment

Only the outermost cells are exposed to the environment

Whole cell is exposed to the environment

Microscope/Macroscopic

Most are macroscopic in nature

Are microscopic in nature

Cell differentiation 

Present

Absent

Cell functions

Different cells perform different functions

A single cell performs all necessary life processes

Life span

Have a comparatively longer lifespan

Have a short lifespan

Effect on injury on the organism

Injury to a cell does not cause the death of the organism

Injury to the cell causes the death of the organism

Reproduction 

May be sexual or asexual

Mostly asexual but sexual reproduction is also seen in the form of conjugation

Autotrophs/Heterotrophs

Includes autotrophs and heterotrophs

Can be autotrophs or heterotrophs

Transportation

Occurs by simple diffusion, active and passive transport

Occurs by simple diffusion

Division of labor

Is at cellular, tissue, organs and organ system level

Is at the organelle level

Eukaryotes/prokaryotes

Includes only eukaryotes

Includes both eukaryotes and prokaryotes

Examples

Humans, animals, plants, birds, and insects

Bacteria, amoeba, paramecium, and yeast