Donna Grubich, age 14„ of Finleyville, P enna. , for her question:
What is a Euglena?
Euglena is the name of a genus of protozoa and, says Andy, this high sounding statement needs some explaining. In science, the animal kingdom is classified in divisions and subdivisions. The big divisions are the phyla, plural of phylum. A phylum is subdivided into classes and a class is subdivided into orders. An order is subdivided into familes and a family is subdivided into genera, plural of genus which brings us back to the high sounding statement. The genus includes a number of species or individuals. When used as a genus name, Euglena is spelled with a capital letter.
The animal phyla are listed from the simple to the more complex, The simplest of all animals are the one celled creatures, too small for our eyes to see. This is Phylum I, Protozoa, a name coined from older words meaning first and life. Most likely the protozoa were the first animals on earth. There is a lot of evidence that the more complex animals developed from simple, one celled ancestors.
The number of different protozoa in the world today is past counting. They swarm in the seas and teem in every drop of pond water. The euglenas thrive in fresh water and the tiny creatures are often so numerous that they add a green scum to the surface of a pond, The Euglena genus is a subdivision of the class Flagellata, a name coined from an older word for whip, The protozoa in this class have little whips or tails which they wave and beat to help them move through the water.
A member of the Euglena genus has a long body tapered at each end. At one end is a gullet and a bright red granule called an eye spot, The word Euglena means eye pupil and it may refer to this eye spot or to the pupil shaped body.
The eye spot, of course, does not see, but it does react to light. When captive euglenas are placed in the shade, they will move over to the brightest side of their dish.
There is the strangest reason why euglenas need to be in the light. The little creatures are green because they contain chlorophyll, the magic material which plants use to make heir food. Animals., of course, get their nourishment from the food they eat and digest. Plants make their own food from air, water and sunlight. This is one of the great differences between the plant and animal world.
Do you remember the sundew, the Venus’s flytrap and the pitcher plants that Andy described last year? These plants devour insects, In this they act like animals, but they are nevertheless plants. When it comes to dining, the euglena is an animal that acts like a plant. Its little body is brim full of green chlorophyll. And this chlorophyll acts just like the chlorophyll in any green leaf. It uses sunlight to make simple sugar from carbon dioxide and water. The euglena has a gullet but, under ordinary circumstances, he does not use it to eat food.