FIVE KINGDOM OF CLASSIFICATION

 

Organisms are divided into different classes based on their anatomy, form and function. This classification of organisms is done in a certain hierarchical view ie the hierarchy of the Kingdom, Phylum, Class, Order, Genus and Species. 

Development of taxonomy

Aristotle first divided the living world into two groups, namely, the flora and fauna. After that, Linnaeus classified all the organisms into plants and animals in his book 'Systema Naturae'. It is because the foundation of modern classification system is laid on the basis of the classification system done by them.In 1969, the traditional bicameral classification system was replaced by the five world system presented by Whittaker. Whittaker classified all creatures into the following five kingdoms:

1. Kingdom Monera: This world consists of prokaryotic organisms ie Bacteria, Cyanobacteria and Archibacteria.

2. Kingdom Protista: This world consists of unicellular eukaryotic organisms. Yuglina, which is situated between plants and animals, is included in this world.

3. Kingdom Fungi: This includes organisms dependent on parasites and dead food for food. Their cell wall is made of chitin.

4. Kingdom Plantae : This world consists of algae and multicellular green plants.

5. Kingdom Animalia : This includes all multicellular animals. It is also called 'Metazoa'.

In 1982, Margulius and Schwartz revisited the five world classifications. It included one prokaryotic and four eukaryotic worlds ie Protista, fungi, plantae and animalia. Currently this classification system is the most recognized.

1. Monera 

It is further divided into Archaebacteria and Eubacteria, of which Archaibacteria are more ancient.

a. Archaebacteria: Most of these are autotrophs and they derive their energy from metabolic activities, sources of chemical energy (eg ammonia, methane, and hydrogen sulfide gas). In the presence of these gases, they can make their own amino acids. They are divided into three classes - methanogens (producing methane), thermoacidophils (adapted to a highly hot and acidic environment) and halophils (growing in a highly saline environment).

b. Eubacteria: They are usually not found in membranes surrounded by organelles. Nucleoid acts as the only chromosome. Photosynthesis and transfer of electrons take place at the plasma membrane.

2. Protista  

a. It includes a variety of unicellular eukaryotic organisms, such as unicellular algae, protozoa, and unicellular fungi.

b. They are autotrophic (eg unicellular fungi, diatom) or heterotrophic (eg protozoa).

c. Examples are unicellular fungi, Chlorella, Euglina, Trypanosoma (the cause of sleeping sickness), Plasmodium, Amoeba, Paramecium, Chlamydomonas (Chlamydomonas) etc.

3. Fungi 

a. This includes plants that are unable to prepare their own food by photosynthetic action.

b. They are heterotrophic and eukaryotic.

c. Some fungi are parasites and obtain nutrients for themselves from the plant on which they live.

d. Some fungi, such as penicillium, are decomposers and receive nutrients from dead substances.

e. In this, food is stored in the form of glycogen.

f. Examples of fungi are yeast, mushrooms, termites etc.

4. Plantae

a. It consists of multicellular plants.

b. They are eukaryotic.

c. Cell wall is found in them.

d. They contain a central vacuole surrounded by tonoplast membrane.

e. They store food for plants in the form of starch and lipids 

g. Plastids are present in them.

h. They are autotrophic, that is, they prepare their own food.

i. The growth of plants is unlimited.

j. Due to branches, their size is uncertain.

5. Animalia

a. Animals have wall less eukaryotic cells.

b. They are hostile.

c. The growth of animals is limited.

d. Often a certain shape and form is found in animals.

e.Gradual levels of cell, tissue, organ and organ system are found in animals.