Nature encompasses alluring and charming organisms one can think of. These creatures can range from the smallest protozoa to the largest mammals. All creatures need food for energy. The method of food capture differs in different groups of taxa. The way protozoa eat their prey is also magnificent. The nutrition mechanism is also amazing. Nutrition is a process of eating, digesting, and assimilating food for energy. The ways in which protozoa obtain their food also vary dramatically. They represent almost all types of nutrition. They can be holozoic, holophytic, parasitic, coprozoic, mixotrophic, saprozoic.
1. Holozoic Nutrition
Most protozoa feed in the same way that higher organisms did. They can feed on various microorganisms, rotifers, crustaceans, other protozoa, etc. These protozoa are called holozoic. They can be carnivores, herbivores, omnivores, or rugged. Holozoic nutrition is also called zootrophic nutrition. This type of nutrition involves three basic steps:
A. Capture and ingestion of food
The usual method of eating food is also called phagocytosis, which differs greatly in the different classes of protozoa. Locomotor organelles play an important role in the capture and ingestion of food. Rhumbler has defined four methods in which locomotive organelles participate in the capture and ingestion of food.
For. Ring road
This method is very common amoeba. Here the prey is surrounded by the locomotor organelle called pseudopodia from all sides without coming into direct contact with the prey and a cup is formed. The food cup is later completed by forming a food vacuole that encloses the prey with a large amount of water.
B. Circumfluence
This method is aided by locomotor organelles called axopodia and reticulopodia to capture immobile prey. A food cup is formed by direct contact with the prey and the cytoplasm flows around the prey to engulf it.
vs. Invagination
In this case, the prey is first killed by a toxin secreted by the pseudopods and then enclosed in the form of a food vacuole together with the cytoplasm.
D. Import
In this case, passive prey such as filamentous algae simply enters the body on contact and is ingested. The general body surface plays an important role in this process.
B. Digestion and assimilation
Digestion is always intracellular. The food vacuole is surrounded by a film. Acids, alkalis, and enzymes are poured onto food to ensure digestion. The reaction is first acidic and then alkaline. The prey dies in an acidic environment that lasts from 4 to 60 minutes. Digestion occurs mainly in the alkaline phase. Lysosomes help digestive enzymes. Proteases that break down proteins and amylases that break down starch are widely occurring. The presence of fat-busting lipase is controversial.
C. Egestion
In naked forms like Amoeba, undigested matter comes out of the back of the body. In some ciliates, egestion occurs through a permanent opening at the back of the body called the cytopia.
2. Holophytic nutrition
This mode of nutrition is also called autotrophic nutrition. This is very common in chlorophyll-bearing flagellates. These organisms photosynthesize with the help of carbon dioxide, water, and chlorophyll. Oxygen is released and the carbon that remains is used to make food. Starch is stored as amylum, but in Euglena it is stored as paramylum, which is not stained blue with iodine. Certain protozoa harbor symbiotic green algae that photosynthesize and provide food for them.
3. Saprozoic nutrition
This mode of nutrition is also called osmotrophy. Flagellates that are in direct contact with the organic matter of decomposed plants and animals get their food here. They get their food in the form of dissolved material.
4. Pinocytosis
This is also called a cellular drink and was first studied by Mast and Doyle in 1934 in Amoeba proteus. Pinocytotic channels are formed in the body to absorb liquid food from the surrounding environment. This method helps the body obtain higher molecular weight compounds from the surrounding environment.
5. Parasitic nutrition
Sporozoans are completely parasitic and feed by living as parasites in the bodies of other animals. They are divided into two categories:
For. Diners
They feed on the raw or digested material of the host in a saprozoic way. They are harmless endocommensals. For example, Nyctotherus, Balantidium
B. Pathogen
About 26 species of protozoa are known to be parasites of humans. They are responsible for causing frightening diseases like sleeping sickness, malaria, etc.
6. Coprozoic nutrition
Many free-living protozoa feed on the fecal matter of other animals and are called coprozoa. For example, Cercomonas, etc.
7. Mixotrophic nutrition
Various protozoa can obtain their nutrition in more than one way. Euglena gracilis is capable of taking nutrition both holophytic and saprozoic.
Whatever the means of devouring food, they all lead to adaptation to a colossal environment.