Two kingdom classification

Carolus Linnaeus classified the living organisms in a systematic way. He proposed the two kingdom classification system. 

[tabby title=”Material”]

Two kingdom system

Organisms are vastly diversified in their characters. All living organisms differ in their structure, form, life cycle and metabolism. These numerous organisms are classified into different groups for easy identification and understanding. The father of classification is Carolus Linnaeus. He was the pioneer of modern biological nomenclature. He classified the organisms into two kingdoms.

Two Kingdom Classification was proposed by Carolus Linnaeus in the year 1758. He classified all living things into two kingdoms, they are Animal kingdom and Plant kingdom. He named for animal kingdom as Regnum Animale and plant kingdom as Regnum vegetable. This two kingdom classification laid the base for modern classification. In his classification, he has distinguished clearly animals from plants.

The plants synthesize their own food and it is fixed in the soil. There is no movement in the plants. On the other hand, animals are depending on other plants and animals for their food. Animals are freely movable. These are the basic and important differences between plants and animals.

Kingdom Plantae

The plant kingdom includes green plants, mosses, ferns, many colorless and colour unicellular organisms, molds, fungi, lichens, bacteria and multicellular seaweeds. This classification was proposed by Linnaeus. Following are the few distinguishing characters of plants.   

• Plants vary greatly in form and size. The body is usually asymmetrical. In higher forms of plants structures like leaves and plants have a definite shape and form.
• Plants do not have the capability to move and they are fixed with root in the soil. But few localized movements may occur in plants.
• There is a continuous growth in their lifespan.
• I plants nutrition is autotrophic or saprophytic. Minerals are absorbed in solution state roots will not absorb the particulate matter.

The plants body is having a distinct cell wall. The plant cells have a vacuole filled with sap and plastids of different kinds. Centrioles and lysosomes are absent in plant cell. The reserve food in plants are in starch form.

The plant kingdom is classified as follows

Kingdom Animalia

Kingdom Animalia including multicellular organisms and unicellular protozoans. These organisms have no chlorophyll and photosynthetic capability. This was proposed by Carolus Linnaeus. This is including protozoans, sponges, jellyfish, worms, crabs, insects, spiders, frogs. Snails, sharks, bony fishes, lizards, birds, and mammals. The distinguishing characters of animal as follows

• The animals show a definite shape, form and symmetry.
• Animals are capable of moving from one place to another place.
• The growth of the animal occurs proportionately in all body parts.  
• They respond to stimulus.
• Animal body is made up of cells but without the cell wall. Plastids and vacuoles are absent. Centrosomes and lysosomes are present.
• Some necessary amino acids, vitamins, and co-enzymes, some necessary amino acids cannot be synthesized by animals. They must be taken from outside.
• In plants, food is reserved in the form of glycogen.

Classification of kingdom Animalia

Demerits of Two kingdom classification

This system is not suitable as due to a large diversity of among the organisms. The main demerits are as follows

• Euglena possesses characters of both plants and animals and they are not classified in a particular group.
• The differences between Plantae both photosynthetic and nonphotosynthetic organisms are placed together.
• Lichens are not included either plant kingdom nor animal kingdom.
• Diatoms are placed in the plant kingdom but protozoans are placed under the animal kingdom
• Euglena and Chlamydomonas having characters of both animals and plants. So they can belong to any kingdom.
• Nutrition modes in two kingdom classification system are ingestion and assimilation. Absorption type of nutrition was not recognized at that time.

[tabby title=”Lecture”]

[tabbyending]