The differences between free living and parasitic protozoans include temperature change, movement, where it lives, and its ecological impact. Protozoans are bacteria. Some bacteria help to break down organisms in the soil and compost. They help with ecology. They also are food for fish and small animals and plants.
Protozoans also show differences in the amount of heat that they tolerate. Some can only survive if temperatures are higher than 70C degrees. Others will die when temperatures are more than 30C degrees. Others die at 50C.
These single-celled, microscopic organisms are animal-like. The three types are amoeba, paramecium, and euglena. Each one has a different way of moving. Amoeba has a false foot. Paramecium has a hairy body. Euglena uses a whip-like tail to move in the water or organism.
Amoeba is the smallest of the protozoans. It lives on leaf surfaces and in ponds and rivers. Under a microscope, it looks like a gray blob. The paramecium is larger than the amoeba. It lives in ponds and swamps. It resembles the ridges on the sole of a shoe. It has two nuclei. The large one controls the organism. It uses the smaller nucleus for reproduction. Euglena has the shape of a pear. It contains chlorophyll. It has a bright red eye spot. These are the protozoans which causes the most harmful illnesses.
Soil protozoa help in turning some bacteria into minerals needed by other plants and animals. Ammonium is only of those important minerals. Soil protozoa also control the growth of other bacteria working as a gardener to prune access and enhance growth. Forests have more amoeba and euglena in the soil.
Another difference in protozoans is that some are harmful to humans and animals while others are helpful to them. According to Landers University, these cause 25% of all diseases. The harmful protozoans occur in water and moist areas. Most people know it as Giardia. Two other harmful protozoan diseases are trypanosome, leishmania, dysentery, and malaria. Giardia is the least harmful but it causes pain and oftentimes severe diarrhea.
One-celled organisms that live in the lining of the intestine of an infected animal cause giardia. When it is inside an animal or human, it moves around with flagella then attaches to the intestinal wall. The flagella reproduce by dividing in half and continue attaching themselves to the intestinal wall until a wall of flagella forms blocking the host’s own intestinal wall thus blocking normal digestion. When the wall is complete, giardia contaminates its environment.
The most harmful protozoans form a hard cyst around their bodies. Nothing can penetrate this cyst to kill it and remove the symptoms. When the cyst has embodied the cell, it can live outside of the organism where it formed. In this way, it spreads the disease to others.