What is the Difference Between Amoeba and Euglena

The main difference between Amoeba and Euglena is that Amoeba moves by pseudopodia whereas Euglena moves by flagella.

Amoeba and Euglena are two genera of unicellular protists that contain a single nucleus. Furthermore, Amoeba is heterotrophic and phagocytosis is its mechanism of obtaining nutrition while Euglena is a mixotroph that undergoes photosynthesis and it obtains nutrients through ingestion.

Key Areas Covered

1. Amoeba
     – Definition, Characteristics, Importance
2. Euglena
     – Definition, Characteristics, Importance
3. What are the Similarities Between Amoeba and Euglena
     – Outline of Common Features
4. What is the Difference Between Amoeba and Euglena
     – Comparison of Key Differences

Key Terms         

Euglena, Amoeba, Flagella, Heterotroph, Mixotroph, Phagocytosis, Pseudopodia

Amoeba – Definition, Characteristics, Importance

Amoeba is a genus of unicellular eukaryotes living in freshwater ponds and wet soil. However, some of them are parasitic inside animal bodies. Moreover, ameboid cells have irregular shapes with a diameter of 0.1 mm. Their cytoplasm has two layers known as endoplasm, the inner layer, and the ectoplasm, the outer layer. Other components of the ameboid cell are the membrane-bound nucleus, food vacuoles, and contractile vacuoles.

Figure 1: Amoeba

Furthermore, the locomotion of Amoeba occurs by forwarding its cytoplasm through the formation of a pseudopodium or a false foot. And, this movement is known as an amoeboid movement. Generally, Amoeba ingests bacteria, algae, plant cells, and other microscopic organisms in a mechanism known as phagocytosis. Their digestion occurs inside a vacuole and the elimination of waste occurs through exocytosis.

Figure 2: Amoeba Structure

Moreover, the asexual reproduction of amoeba occurs either by binary fission and the formation of spores. Under favorable conditions, binary fission produces daughter cells by mitotic cell divisions of a parent cell. Spores are formed in dry or unfavorable conditions and during insufficiency of food. Furthermore, amoeba is sensitive to external stimuli such as the change in light, temperature, and chemicals. It is sensitive to touch as well.

Euglena – Definition, Characteristics, Importance

Euglena is another gens of protists, containing green, unicellular, freshwater organism with a flagellum. Moreover, it consists of the characteristics of both animals and plants. That means; euglena has chloroplasts scattered throughout the cell. Therefore, when the light is available, it can undergo photosynthesis. Pyrenoids, which are micro-compartments inside the chloroplasts, operate carbon-concentrating mechanisms. Also, Euglena stores food in the form of starch inside granules.

Figure 3: Euglena

Furthermore, the animal-like characteristics of euglena include the presence of an eyespot, which detects light. It also lacks a cell wall. A protein layer is arranged around the cell known as a pellicle, providing flexibility and contractility to the cell. And, this pellicle is held by microtubules. Moreover, the locomotion of Euglena occurs through the movement of flagella. The type of movement is known as metabolic. Its contractive vacuole is known as myoneme, and it helps in locomotion as well as excretion and osmoregulation.

Figure 5: Euglena Structure

Furthermore, Euglena is capable of undergoing photosynthesis while taking nutrients through ingestion into the cell. Therefore, it shows both autotrophic and heterotrophic characteristics. Thus, the mode of nutrition in Euglena is mixotrophic.

Similarities Between Amoeba and Euglena

• Amoeba and Euglena are two genera of animal-like protists.
• Both are single-celled eukaryotes. They may live as single organisms or in symbiotic colonies.
• Also, both have a single nucleus in the cell.
• Moreover, they are mobile but do not contain cilia.
• Both take nutrients through ingestion.
• Besides, both reproduce through binary fission.
• And, both are sensitive to external stimuli such as light, temperature, chemicals, and touch.

Difference Between Amoeba and Euglena

Definition

Amoeba refers to a single-celled animal that catches food and moves about by extending fingerlike projections of protoplasm while euglena refers to a green single-celled freshwater organism with a flagellum, sometimes forming a green scum on stagnant water. Thus, this explains the fundamental difference between amoeba and euglena.

Habitat

While amoeba is free-living in damp environments or parasitic, euglena lives in freshwater and salt water.

Locomotion

Above all, the main difference between amoeba and euglena is that amoeba moves by pseudopodia while Euglena moves by flagella.

Shape

Amoeba does not have a defined shape while Euglena has a defined shape. 

Photosynthesis

Moreover, amoeba does not undergo photosynthesis while Euglena undergoes photosynthesis.

Mode of Nutrition

Another difference between amoeba and euglena is that the amoeba is a heterotroph while Euglena is a mixotroph.

Conclusion

Amoeba is a free-living or parasitic protist. It moves by pseudopodia and ingests food particles through phagocytosis. Therefore, amoeba is a heterotroph. Euglena, in contrast, is a protist that lives in aquatic environments. Its moves through flagella. Moreover, it has chloroplasts in order to undergo photosynthesis. Moreover, it obtains nutrients by ingestion. Therefore, the main difference between amoeba and euglena is their locomotion and mode of nutrition.

References:

1. Vidyasagar, Aparna. “What Is an Amoeba?” LiveScience, Purch, 2 Apr. 2016, Available Here.
2. “Identifying Euglena: under the Microscope.” Actforlibraries.org, Available Here.

Image Courtesy:

1. “Ameboid Protozoa: Amoeba proteus” By Berkshire Community College Bioscience Image Library (Public Domain) via Flickr
2. “Amoeba (PSF)” By Pearson Scott Foresman – Archives of Pearson Scott Foresman, donated to the Wikimedia Foundation (Public Domain) via Commons Wikimedia   
3. “Euglena sp” By Deuterostome – Own work (CC BY-SA 3.0) via Commons Wikimedia   
4. “Euglena diagram” By Claudio Miklos – Simple English Wikipedia (CC0) via Commons Wikimedia