You’ll have to get your microscope out to see these tiny animals.

Protozoa are single-cell organisms that can be found in freshwater ponds and rivers, the sea or in moist soil. They are divided into four groups, namely amoeba, ciliates, flagellates and sporozoa.

Fun fact
There are more protozoa in the world than any other animal.

Amoeba
During feeding, this type of protozoan extends its body until it has completely surrounded its food. It then secretes special enzymes that help to break the food into smaller particles before converting the food
particles into energy to move. This process of feeding is known as phagocytosis.

Did you know?
There is a dangerous amoeba called Entamoeba histolytica, transported through infected water supplies, that causes illness in humans. It travels through your digestive system to your intestine, where it causes infection.

These tiny animals’ bodies are lined with minute, hair-like projections called cilia, used for movement. The cilia move back and forth very quickly, helping the animal propel itself forward.

Ciliates feed on bacteria. They capture food in mouth regions located on their sides. Enzymes then break down the bacteria into energy.

Did you know?
Ciliates are useful in the treatment of raw sewage. They remove harmful bacteria before it reaches the ocean.

Sporozoa
This little animal is different from the rest because it cannot move on its own. Instead, it must live inside a host To survive. Sporozoa are therefore considered largely parasitic.

Did you know?
A plasmodium is a typical example of this kind of para-site. It’s carried by mosquitos who then infect humans by biting them. This parasite infects the liver, causing high temperature and headaches.

Flagellates
This group of protozoa has flagella, which are small, whip-like extensions similar to cilia but larger and fewer in number. They wave the flagella in order to propel themselves forward, or to attract food in their direction.

Did you know?
The parasitic flagellate Trypanosoma brucei is carried by the Tsetse fly, found in East Africa. The fly injects this flagellate into whoever it bites, causing sleeping sickness, a life-threatening disease.
Converting the food particles into energy to move. This process of feeding is known as phagocytosis.