Paramecium caudatum Once known as ‘slipper animals’
When you see the shape of this single-celled organism, you will immediately understand why it was originally referred to as a slipper animal.
Javelin thrower
The paramecium has a highly sophisticated defence system. Just beneath its cellular envelope are many tiny harpoons (trichocysts) that it uses against enemies. These spear-like structures can also be used for other purposes, such as hunting other microbes and attaching the paramecium to the substrate. The spears are also toxic to some microorganisms, with a paralysing effect that enhances their efficacy.
The spears are about 20 micrometres (0.02 mm) in length. If converted to human proportions, they would be about 10 cm long – much shorter than the 2.7-metre javelins thrown at the Olympics! But while human athletes can only throw one javelin at a time, the paramecium has thousands that it can fire off all at once if necessary.
Cilia
The paramecium is also known as a ciliate due to the many hair-like cilia covering its outer surface. These cilia all move in unison, enabling the paramecium to swim rapidly in a specific direction.
Salty inside
The inside of a paramecium is strongly saline compared to the fresh water in which it lives. As a result, it naturally absorbs water by osmosis. To prevent it ‘filling up’ and bursting, the paramecium has two contractile vacuoles that collect the excess water inside the cell and pump it back out again. The paramecium mainly eats bacteria, which it gathers in by moving the cilia in its mouth groove. Once it has taken the bacteria into the cell, the paramecium encapsulates them in food vacuoles and digests them. In turn, the paramecium is fed upon by zooplankton, small fish and other aquatic animals.
Want to learn more about microbes?
Paramecium caudatum is just one of the many microscopic organisms on display at ARTIS-Micropia, each and every one of them with its own unique role in our world. Come by and discover them all!