Species: P. bursaria 
Figure 11: Paramecium bursaria; magnification 400x
Why does the organism belong in this Kingdom?
Paramecium bursaria, a unicellular organism, is part of the Domain Eukarya because it is the only Domain that includes Eukaryotic organisms. The Paramecium bursaria is a eukaryote because of the organelles it consists of. Some of the organelles it has are single micronucleus and macronucleus. The micronucleus is used for the mode reproduction. The macronucleus is the commander and the controller over the metabolism and the growth. The food vacuole is where the food is obtained and function as a storage. When the substance is not needed anymore a food vacuole moves along the cytoplasm towards the anal pore. Furthermore, the mode of reproduction for this organism is asexual via binary fission. They are also capable of partner conjunction. Partner conjunction is used when two paramecia maximize survivability when needed most.  Paramecium bursaria are dependent on zoochlorella, a green algae. It provides chloroplast and large concentrations of carbohydrates used by Paramecium bursaria to metabolize and use as food source. The Paramecium bursaria, is a mixotrophic. This allows the organism to become independent of external food sources. In return to the Zoochlorella, the Paramecium bursaria provides Co2 to be used in its own metabolism which is completely separated from the Paramecium bursaria.  In the kingdom Protista, the organism could either be unicellular or multicellular. The mode of reproduction could be sexually, or/and asexually via binary fission. In addition, the nutrition is obtained by sunlight, consuming organic material or both which is called mixotroph. A mixotroph is when an organism is lacking something and depends on another organism to provide.  What makes the Paramecium bursaria not be able to be classified into the Kingdoms Plantae or Fungi is because they have no motility. The motility of a Protist consists of flagella to swim around and move or/and pseudopodia. It can even have little cilia covering the organism. Paramecium bursaria consist of cilia. This cilia would help the organism swim within the water, or help move food substance through the oral groove, sweeping it through mouth until it reaches the food vacuole.  The reason the Paramecium bursaria cannot be classified in the Kingdom Animalia because itcan be a mixotroph. Also, they can’t obtain a source of energy from the sunlight like the Paramecium bursaria can. Also, the Kingdom Animalia consist of having a nervous system present, which the Paramecium bursaria does not have. Therefore, the Paramecium bursaria is only able to be classified in the Kingdom Protista.
The Paramecium bursaria is around 80-150 μm in length. This organism is found in freshwater only, where there is an abundant amount of green algae called zoochlorella. The Paramecium bursaria is part of a group called the ciliate protozoans.  The shape of this organism gives it reason to be associated with the Paramecium Genus. The shape looks like a slipper or a cigar with the membrane covered in cilia. The cilia on the sides helps bring food into the organism and what helps the organism be motile. The oral groove on the Paramecium bursaria is there to act as the contractile vacuole. The contractile vacuole is there to regulate the concentration of water against osmosis. Even though this organism is unicellular, it contains many organelles, each with their own job. One of the important methods to see this organism to is to have light. 
The main thing that the Paramecium bursaria is known for is its relationship with the zoochlorella. The Paramecium bursaria is green because of its symbiosis with the green algae. They are connected with the Paramecium bursaria. They even grow and divide with the Paramecium bursaria at the same time, coordinately. The two different organisms trade different substances they need. The symbionts receive nourishment and sunlight from its host.  The algae provides the Paramecium bursaria with food in return. One of the substances the Chlorella provides the host with is a photosynthetic product, like maltose. The algae also has high levels of oxygen, providing the Paramecium bursaria with an oxygen supply. This beneficial relationship helps the Paramecium bursaria grow.  The zoochlorella enters through the food vacuole. If there aretoo many at a time, or infected algae enter the organism, it can cause serious changes to the digestive tract of the Paramecium bursaria. 
Figure 12: Paramecium bursaria
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