What is Amoeba?
An amoeba can constantly change shape constantly.
This is because the body consists of a fluid flowing central endoplasm and outer gelatinous ectoplasm. The amoeba contains flowing extensions of the body called pseudopodia, which are used in movement and feeding.
An amoeba can be naked or contain a shell made of mineral particles out of which the pseudopodia extend. They feed by surrounding a food item with the pseudopodia which flows out and surrounds the food, forming a food vacuole.
Amoebas undergo asexual reproduction in the form of binary fission. When conditions are unfavorable they can form a dormant cyst stage where they form a cyst that encloses the organism.
Amoebas can be commensals or parasites in the guts of animals.
What is Paramecium?
The body of a paramecium does not change shape and is covered with fine cilia. There is a distinct anterior end and the body covering is called a pellicle of three membranes.
This pellicle contains cilia. In paramecium there are two inner membranes that are folded in to form large vesicles called alveoli that are found at the base of the cilia.
Paramecium swims forward in a spiral motion because of the way cilia are arranged around the axis of the body.
In Paramecium the buccal cavity, cytostome and cytopharynx form a ciliated funnel found at the posterior region of the lateral oral groove.
Cilia produce a current that moves food into the funnel where it is then taken up into a vacuole.
They have a distinct “mouth” region called a cytostome.
There can be more than one nucleus in the cell, with some species having macronuclei and micronuclei.
Reproduction is by fission (asexual) and conjugation (sexual). During reproduction the nuclei have to divide. Paramecium has specific mating types that exchange genetic material during conjugation.
What is the difference between Amoeba and Paramecium?
- Amoeba has pseudopodia while Paramecium has cilia.
- Amoeba can change the shape of the body, Paramecium can’t
- Paramecium has a distinct anterior end while Amoeba does not.
- Amoeba has no oral groove or cytostome, while Paramecium has a cytostome and oral groove.
- Amoeba has one type of nucleus, while Paramecium has at least one macronucleus and micronucleus.
- Amoeba feeds using pseudopodia while Paramecium feeds using cilia.
- Amoeba undergoes binary fission while Paramecium undergoes binary fission and conjugation.
Table comparing Amoeba and Paramecium
- Amoeba has pseudopodia that allow them to feed and move about.
- Paramecium has cilia that they use for feeding and for movement.
- Amoeba and Paramecium both undergo binary fission but only Paramecium undergoes conjugation.
- Both are unicellular Eukaryotes found in water.
Author: Dr. Rae Osborn
Dr. Rae Osborn holds Honours Bachelor of Science degrees in Zoology and Entomology, and Masters of Science in Entomology from the University of Natal in South Africa. She has received a PhD in Quantitative Biology from the University of Texas at Arlington. She was a tenured Associate Professor of Biology at Northwestern State University in Louisiana for 10 years. She also completed an AAS Degree in Information Network Specialist and an AAS in Computer Information Systems, at Bossier Parish Community College in Louisiana.