Euglena, Paramecium and Amoeba

Biologists study living things, and one of the things they do, is to divide living things into groups. For example, they divide organisms into those that have a cell nucleus and those that don’t. Those organisms with a nucleus are further divided into kingdoms — the plant kingdom, the animal kingdom and the fungi kingdom. But there is another kingdom, one that brings together all organisms that aren’t quite plants, animals or fungi. This is the protist kingdom.

Although organisms in the protist kingdom share some features with plants, animals or fungi, they also have unique characteristics. Let’s look at some organisms that belong to the protist kingdom. One of them is small, less than a millimetre in length. It’s made up of only one cell, and its shape and colour make it look almost like a tiny cucumber. This type of organism is a euglena.

The euglena acts like a plant as well as like an animal! It can produce its own food when there is light available, just like plants. This is because the euglena contains special parts, ones which plants have as well — chloroplasts. Thanks to the chloroplasts, the euglena can carry out photosynthesis to produce food. However, if the euglena ends up in a dark place, where it can’t produce its own food anymore, it will feed on other organisms — just like animals do!

Another interesting feature that some euglenas have, is an eyespot! Euglenas can’t see with this eyespot, in the same way you can with your eyes. But they can detect light, and even move towards it. Euglenas can move by whipping around a tail-like structure, almost like a helicopter propeller. Euglenas usually have two tail-like structures that they use to move around with.

But another member of the protist kingdom, moves around differently, using thousands of what look like tiny hairs, covering its whole cell. These hair-like structures operate together, and propel the organism around, in the water where it lives. This organism is called a paramecium. The paramecium is often shaped a bit like the sole of a shoe. It can’t produce its own food, so it uses its hair-like structures not only to move, but to feed, too!

When these hair-like structures move, they create small currents in the water. This drags other organisms closer to the paramecium, and into its mouth. So, euglena and paramecium have fairly stable shapes and move around using hair-like or tail-like structures. But there is another type of protist, that looks a bit like a blob of jelly. This organism is the amoeba.

Like the others, the amoeba is made up of only one cell. It moves around in water, by extending parts of its cell away from its core, and then the rest of the cell follows. These extending parts, sometimes called ‘false feet’, are also used for feeding! When the amoeba comes across a piece of food, such as a bacterium or another tiny organism, first it extends its false feet around the food item, completely surrounding it, and then sucks it into the cell! Species of euglena, paramecium and amoeba typically live in freshwater or saltwater.

Some species of these organisms though, live inside other living things and cause them harm. Euglena, paramecium and amoeba all belong to the protist kingdom, and are made up of a single cell. They do have distinct and fascinating characteristics.