Categorizing The Amoeba

Every single living thing on our planet is made up of small components known as cells.

All organisms, from humans to plants, were once small, respective cells that then broke off and turned into millions. 

Despite this, some creatures are made up of just one cell throughout their whole life.

Categorizing The Amoeba

As they are so small, these can only be seen with a microscope and just need a single cell to live.

One of the most known types of these creatures is called an amoeba. 

It can be hard to understand whether amoebae are part of the human, plant, or fungi kingdom.

We’ll cover the answer in this article, including what amoebae are, their characteristics, and whether they are dangerous or not. 

What Are Amoebae?

Amoebas are single-celled organisms that need to be viewed from a microscopic level.

Many types of amoeba can be located in areas with moist and watery conditions. These include freshwater or damp soil settings, like rivers or lakes. 

Amoebas move by pressing their cytoplasm against their cell membrane, a process called Pseudopodia.

This involves the cytoplasm moving the plasma membrane forwards or backward, resulting in protrusions that resemble fingers.  

One of the main features of amoebae is their ability to alter their form as needed.

These cells can be located inside several types of animals, algae, and sometimes in fungi.

Amoebic cells reproduce asexually, multiplying themselves through binary fission.

Amoebas usually have a short lifespan of just two days. However, as they go through binary fission, the reproduced daughter cells mimic the parent cells. This means that you can think of amoebas as everlasting organisms. 

Appearance Of An Amoeba

Amoebae are made up of cytoplasm and cellular organelles that are housed inside a cell wall.

They have a nucleus that contains the amoeba’s DNA, which is coated by the plasma membrane.

An amoeba’s cytoplasm also has two tiers, the endoplasm inside and the ectoplasm on the outside. 

Other than DNA, the nucleus also contains various types of genetic material which help to create energy and transport protein.

These include a Golgi apparatus, contractile vacuoles, mitochondria, and fat and water globules. 

An amoeba’s whole form is transparent, resembling gelatin. They take in food and sustenance by consuming prey through two methods, phagocytosis and pinocytosis.

If amoebae are living in an unusual environment or aren’t around enough food sources, they can transform into microbial cysts. 

Amoebae eat various types of food, including plant cells, bacteria, and algae, However, unlike us, they don’t have a visible anus or mouth to secrete or excrete waste. 

All amoebae are pseudopods that don’t have a clearly defined shape. We know that amoeba cells are very small, ranging from 250 to 750 microns. However, some amoeba cells can be seen with the naked eye. 

A. Proteus, for instance, is the largest cell currently known to exist within the unicellular organism family.

These well-known amoebae can develop in size to reach 2mm and are distinct from other amoebae as they aren’t pathogenic.

This means that they won’t be able to infect animals or humans to induce disease. 

Amoeba Categories

Categorizing amoeba cells is a debated topic, as they contain a nucleus, but aren’t animals or plants.

For the sake of simplicity, amoeba cells are ranked within the Protista kingdom.

Scientifically, this is portrayed as part of various classes as below:

  • Domain – Eukaryota
  • Species: Proteus, dubia, animalcule, etc
  • Family – Amoebidae
  • Kingdom – Amoebozoa
  • Genus – Amoeba
  • Phylum – Tubulinea
  • Order – Tubulinida

Modern research classes amoeba cells through their subunit ribosomal RNA genes.

After looking at its features and structure in more detail, the most reasonable category to class amoebae in is the group Sarcodina.

However, it’s important to realize that this categorization isn’t established from its evolutionary connections, so this isn’t thought of as a family tree. 

Are Amoebas Harmful To Humans?

Are Amoebas Harmful To Humans?

While Amoeba proteus is an example of amoebae that aren’t pathogenic, other types of amoeba are expedient pathogens.

They can exist as free-living cells, but they favor acting as parasites, infecting hosts to take in nutrients from them. 

Parasitic amoebae can inflict issues on humans, such as amoebiasis or amoebic dysentery.

As they take in food and water, they can begin transforming into a cyst within the host themselves.

This is very dangerous, as the pathogens have a chance of invading the blood, transporting themselves to important organs through the bloodstream. 

An example of a dangerous amoeba cell is the Naegleria fowleri. This type of amoeba is found within warm freshwater sources like ponds and muddy puddles.

They can also be found within untreated pools, spas, and water parks. Though they can exist without a host, they aim to infect and take in sustenance from a host’s body. 

An infection from the Naegleria fowleri amoeba is very dangerous, as this pathogen can reach mucous membranes which line the nose.

Once they enter these membranes, the pathogens can move towards the brain, feeding on important brain tissues, like neurons which carry information throughout the body. 

If this infection isn’t detected promptly, it can cause Naegleriasis, a rare, but fatal condition.

However, as the disease isn’t common, it can be hard to identify and diagnose. Most of the diagnoses occur after the death of the infected individual.  

Fatalities usually transpire within a week after symptoms arise. These can range from headaches and nausea to hallucinations and seizures. Just a few patients around the globe have been noted to survive Naegleriasis. 

Though amoebae can inflict diseases on humans, they are a necessary part of the soil’s ecosystem.

They consume dangerous bacteria within soil to lower their population size. 

This process also recycles nutrients. Bacteria take in nutrients from the soil once they are available, but when amoebae consume this bacteria, the nutrients are freed back into the earth. 


Amoebae are single-celled organisms that can alter their shapes. They can be dangerous to humans as they can be parasites, infecting hosts to thrive on nutrients that they consume. 

Though amoebas carry a nucleus, they aren’t considered animals, plants, or fungi.

Amoebae are classed within the Protista kingdom, though they are also considered to be eukaryotes due to their nucleus.

Jennifer Dawkins

Leave a Comment

Your email address will not be published. Required fields are marked *