Kingdoms of Life Essay

On our planet earth we have what are called kingdoms, 5 to be exact, consisting of a very diverse group of living things. Using these five kingdoms we classify our species and organize information on what we are and what resides with us. When we place every living creature into one of the five kingdoms it better helps us understand the world around us and it’s habitants. The five kingdoms include: Moneran, Protist, Fungi, Plantae, and the one we call home, Animalia.

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1. Monera The simplest of all organisms is the bacteria of the Moneran kingdom. They are broken down into two types: Eubacteria and Archaebacteria. Eubacteria is known as the “true bacteria” which makes up the roughly 10,000 species in the Moneran group. Archaebacteria or “ancient bacteria” if you will, is the minority of the group and are only found in extreme environments including but not limiting; swamps, salt lakes, deep-ocean hydrothermal vent, etc. There are many types of species belonging to the Moneran kingdom that have yet to be discovered.

Monerans are also the only group within the five kingdoms that are all prokaryotes. Prokaryotes are one-celled or colony of cells.

2. Protista In this kingdom we have multi cellular organisms (Protista) which are not a part of nor do they fit, the Animal, Plant, or Fungus Kingdom. In the beginning, protozoa were placed in a sub-kingdom of Animalia but because of the problems this classification had, it later became it’s own kingdom. All members of this phylum have what are known as nucleated cells and live in aquatic habitats (both freshwater and marine). According to Lynn Margulis, K.V. Schwartz and M. Dolan (1994), the cells of all Protoctista originally formed by bacterial symbioses or symbiogenesis. Members of this kingdom are not considered animals because they do not come from an embryo, they are not plants nor are they considered fungi because they do not develop from spores.

3. Fungi There are some members of the Kingdom Fungi that are associated with algal cells of the Kingdom Protista and/or prokaryotic cyanobacteria of the Kingdom Monera. Fungi plays a very critical role in nature’s continuous rebirth: Fungi actually recycle all dead organic matter turning it into useful nutrients. Fungi consits of species like: mushrooms, molds, mildews, stinkhorns, rusts, puffballs and many others. There are on estimate 100,000 known species today with hundreds of new species being discovered each year.

4. Plantae With over 1.6 million species of living organisms on earth and new species discovered every single day, in particular; insects and nematodes residing in rsecluded tropical regions. However, with the present rate of destruction, a majority of the virgin tropical rain forest are headed straight for extinction, leaving millions of species undiscovered by the human race. It is the theory that approximately 99 percent of species that ever resided on earth were extinct long before the human ever set foot on this planet. Even with humans having such an incredible significance to the development of earth, technically they are considered to be newcomers on this marvelous planet. If all theories are correct, earth is aged at about 4.5 billion years old, meaning the ancient life forms (such as the cyanobacteria) appeared roughly 2-3 billion years ago. 5. Animalia

There are nine phyla of this kingdom including the following: Porifera (poriferans), Cnidaria (cnidarians), Platyhelminthes (flatworms), Nematoda (roundworms), Annelida (annelids), Mollusca (molluscs), Arthropoda (arthropods), Echinodermata (echinoderms) and Chordata (chordates). Animals are considered to be part of this group because they are all multi-cellular organisms whose cells are connected by a plasma membrane and not by a cell wall of cellulose like the others.

The differences between plants and animals led to the division of all life into what is known as (referenced above) Plantae and Animalia. In animals, the cells are organized into tissues and specialized tissue systems that permit them to move freely in search of food. They build energy by acquiring and ingesting their food, unlike plants, which use the system photosynthesis to benefit from the nutrients they need to survive. A well developed nervous system with sensory and motor nerves is what enables animals to receive environmental stimuli as well as a response to the environment around them. It was found that some were plant like while others (protozoa) resembled animals in that they obtain locomotion by means of flagella and that they actually digest food.

The Animal Kingdom holds the most species of all of the kingdoms, ringing in a little over one million. Interesting fact, is that more than half of the animal species are insects. The result of 300,000 beetles plus the 800,000 different insect species a make up the largest order of insects (one fifth of all species–using a total of 1.5 million). It has been said that if the species between plants and animals on earth were lined up at random, every 5th species would be a beetle.


Viruses are out of the Kingdom assortment completely and sometimes they are said even to belong to their own kingdom, the kingdom Virus. The small and less complex infectious agent is made of tiny macromolecular units composed of DNA or RNA covered by an outer protein coat. Virus’ do not contain membrane-bound organelles, ribosomes, a cytoplasm, or any other source of energy formation of their own. They do not have the self-maintenance metabolic reactions of living systems, they lack cellular respiration and gash exchanges. They are completely capable of reproducing but only at the expense of a host cell. They can and will only survive as minute macromolecular particles outside of their body. Plant viruses are transferred between each other by insects that feed on sap, such as aphids, while animal viruses can be carried by blood-sucking insects (mosquitos for instance).

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