The 5 kingdoms of nature: Animalia, Plantae, Fungi, Protista, and Monera - Meanings

The 5 kingdoms of nature: Animalia, Plantae, Fungi, Protista, and Monera - Meanings
Posted on 09-02-2022

5 kingdoms

What are the 5 kingdoms?

The 5 kingdoms of nature are the Animalia (animal) kingdom; Plantae (plants); Fungi (fungi); Protista (protozoa) and Monera (prokaryotic organisms). It is a classification system for living things created by ecologist Robert Whittaker in 1969.

Let us remember that a kingdom is a classification category in which living beings are grouped according to the relationship between their species. And although this classification of the 5 kingdoms is the most popular, it is not the most up-to-date.

Since 2015 there is a new classification of 7 kingdoms of nature that proposes the AnimaliaPlantaeFungiChromista, Protozoa, Bacteria, and Archaea kingdoms. This classification was created by the American biologist Michael Ruggiero.

In any case, the system of the 5 kingdoms continues to spread, so it is useful to learn more about its characteristics and classification.

Characteristics of the 5 kingdoms

Each kingdom of nature groups living beings with similar characteristics, based on certain criteria, such as:

  • Cell type: eukaryotic (without a defined cell nucleus) or prokaryotic (with a defined cell nucleus).
  • Type of cellular organization: unicellular (organisms with one cell) multicellular (organisms with more than one cell).
  • Respiration: aerobic (need oxygen to live) anaerobic (do not need oxygen).
  • Nutrition: autotrophic (they generate their own food), heterotrophic (they feed on compounds generated by other organisms).
  • Reproduction: sexual and asexual
  • Locomotion: autonomous (can move) or immobile (cannot move).

Kingdom Animalia (animals)


Rabbits are invertebrate organisms that belong to the Animalia kingdom.

Mammals (including humans), fish, birds, reptiles, amphibians, molluscs, insects, and worms belong to this category.

These types of living beings are characterized by having eukaryotic cells, that is, with a defined nucleus, they breathe oxygen, feed on other animals, and can move by themselves.

Within this realm, there are two categories:

Invertebrate animals: They do not have a backbone. For example, the earthworm, the octopus, the spider.

Vertebrate animals: they have a backbone. For example the dog, the bat, the sea turtle, the rabbit, the human being.


Kingdom Plantae (plants)


The redwood is a living being that belongs to the Plantae kingdom and can live up to 1,800 years.

All plant species belong to this kingdom. These are characterized by being organisms whose cells have a defined nucleus (eukaryotes), also cannot move by themselves, and produce their own nutrients in a process called photosynthesis, which means that they are autotrophic.

Today, many species that were considered to be part of the Plantae kingdom are placed in the Chromista kingdom of the 7-kingdom classification.

Some examples of plants are sequoia, monstera, pine, orchid.


Kingdom Fungi (fungi)


The false cape caps ( amanita muscaria ) belong to the Fungi kingdom and are a type of poisonous mushroom.

For a long time, fungi were considered to be plants. Today they have their own kingdom since they have defined characteristics, such as the fact that although they have a defined cell nucleus (like plants), they reproduce asexually through spores.

Spores are microscopic organisms that, in the fungal kingdom, function as reproductive cells. In this case, these types of cells do not need to mate, since they can reproduce on their own. For this reason, reproduction is asexual.

Examples of fungi are mushrooms and mold.


Kingdom Protista (protozoa)


Brown algae are an example of organisms that belonged to the kingdom Protista.

According to the old classification of the 5 kingdoms, Protista is the kingdom of all organisms with a defined nucleus (eukaryotes), which cannot be classified as animals, fungi, or plants.

In the most recent classification, the Protista kingdom was renamed the Protozoa kingdom. On the other hand, some of the organisms that belonged to this category are now part of the Chromista kingdom, according to the current classification of the 7 kingdoms.

Some examples of organisms that belonged to the Protista kingdom are brown algae, ciliates, which are microorganisms that live in water, and most aquatic molds.


Kingdom Monera (prokaryotic organisms)


Escherichia coli is a bacterium present in the human digestive tract.

In the 5-kingdom classification system, Monera is the category to which single-celled (unicellular) organisms without a defined nucleus (prokaryotes) belong.

Today it is known that the organisms of the Monera kingdom are actually two different groups: the archaea and the bacteria. These two groups have their own kingdoms in Ruggiero's proposed classification: kingdom Archaea and kingdom Bacteria.

Examples from the ancient kingdom Monera may be the bacillus Clostridium botulinum, which causes botulism, and Chlamydia, a bacterium responsible for some sexually transmitted diseases.


Classification of living beings: how many kingdoms are there?

Throughout history, different classification systems have been created for living beings. One of the most popular and used has been that of the 5 kingdoms, created by Robert Whittaker in 1969. His classification was taught for decades and still appears in school books.

However, the most recent classification is that of the 7 kingdoms, proposed by the biologist Michael Ruggiero in 2015. This hierarchy is part of the Catalog of Life System ( Catalogue of Life or CoL), a scientific project created precisely to unify the criteria classification of living beings.

This system contemplates the kingdoms AnimaliaPlantaeFungiProtozoaChromistaArchaea, and Bacteria. In the 5-kingdom system, archaea and bacteria belong to the Monera kingdom, while organisms from the Protista kingdom are now part of the Protozoa and Chromista kingdoms.


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