Unicellular Organisms and Multicellular Organisms

The basic difference between Unicellular Organisms and Multicellular Organisms is that Unicellular organisms are those that are made up of a single cell, for example, bacteria and yeasts; multicellular organisms are those that are made up of two or more cells, for example, the shark, the vulture, the eucalyptus.

What are unicellular organisms?

Unicellular organisms are microscopic organisms that gather all their vital functions in a single cell. Almost all prokaryotic organisms (having cells without a cell nucleus) and some eukaryotic organisms (having cells with a cell nucleus) are unicellular.

Within the Monera kingdom, all bacteria are unicellular organisms, for example escherichia coli, salmonella typhi, and all archaea, for example, the methanogenic archaea. Within the fungi kingdom, yeasts, for example Pichia, saccharomyces cerevisiae (brewer’s yeast ); within the kingdom Protista, the protozoa, for example, the paramecium and the dinoflagellates.

Characteristics of unicellular organisms

They are present in all ecosystems.
The number of them far exceeds multicellular organisms.
They are considered more primitive than multicellular organisms.
They reproduce asexually.
There are heterotrophic and autotrophic unicellular organisms.
They can group together forming colonies.

Examples of unicellular organisms

Amoeba	Cyanidiophytina	Yeast
archaea	diatom	microalgae
Bacterium	Dinoflagellates	paramecium
Chlorella	Euglena	protozoa

Read Also: Unicellular organisms

What are multicellular organisms?

Multicellular organisms are made up of two or more cells that specialize in different vital functions (neurons, epithelial cells, red blood cells). These specialized cells form tissues that in turn make up the organs of the living being.

All animals and plants are multicellular organisms, for example, mammals like the lion, amphibians like the frog, trees like the oak, and herbaceous plants like the onion. Some fungi and some organisms of the Protista kingdom are also multicellular, for example, mushrooms, and algae.

Characteristics of multicellular organisms

They are also called multicellular.
They are eukaryotic organisms.
They are made up of specialized cells that can be very different from each other.
The cells that make them up are related to each other and need each other.
They are microscopic organisms more complex and developed than unicellular organisms.
They initially arise from a single cell that multiplies through mitosis or meiosis.

Examples of multicellular organisms

Avocado	kelp	Dog
Brown algae	Lettuce	Porphyra
Horse	Daisy flower	portobello
Chicken	Mosquito	Oak
Sparrow	nematodes	Chinese mushroom
Hydrangea	Palmaria palmata	black truffle