Lin Laker, age 12, of Indianapolis, Ind., for her question:
WHAT ARE FLAGELLATES?
Zillions of flagellates thrive in the world of minicreatures, too small for our eyes to see. In teeming swarms they often add green or yellowish tinges to freshwater creeks and ponds. Other types live in salty sea water, and sometimes their population explosions cause devastating red tides that wipe out the fishes.
The frisky flagellates are a group of tiny singlecelled protozoans. All of them have tails called flagella, which they wave to and fro to propel themselves through the water. Most of them have somewhat oval shapes, more rigid than the famous amoeba, which is another type of protozoan.
The average flagellate is stuffed with green chlorophyll, which uses solar energy to manufacture carbohydrates. These food supplies are stored within the tiny cell. One type is the busy euglena, shaped like a mini green slipper with a wispy tail and a bright red eye spot. This remarkable eye spot is a light sensitive organ that guides the euglena to sunny locations.
The amazing volvox is a colony. of thousands of flagellates, shaped like a merry little ball, perhaps one tenth of an inch wide. The ball is hollow and the flagellates are stuck to its jellified surface, where each waves its tiny tail.
In some mysterious way, the volvox colony co operates to form a front and a rear. Somehow the wispy tails wave in unison to progress forward and the little ball swims in a rolypoly style through the water. The flagellates toward the front have larger eye spots, no doubt to detect the sunny direction. Those toward the rear concentrate on reproduction.
The two tailed dinoflagellates have tight coats of cellulose plates, and some contain globules of oil to keep them afloat in salt or fresh water. The colorless types capture and digest food. When agitated by pounding waves, some types shoot sparks or add glowing luminescence to the water.
Certain red dinoflagellates teem in salt and fresh waters. Sometimes their fantastic population explosions cause those wretched red tides that poison or suffocate all the other creatures in the water.