HISTORY OF CLASSIFICATION:

In 700s, ABU-USMAN UMER AIJAHIZ described  the characteristics of 350 species of animals in his book . He wrote a lot about the life of ants. In 1172, IBN RUSHD translated  Aristotle,s book “ de anima”

TWO-KINGDOM:

According to old system all organisms classify into two  kingdoms ,     plantae and animalia.

Plantae:

All organisms which can prepare Food from simple inorganic materials and store energy , are autotrophs and include in kinddom Plantae.

Animalia:

The Organisms that cannot synthesize their food and depend on autotrophs  , these are heterotrophs and are include in kingdom animalia .

According to this system  , bacteria , fungi , and algae were included in  kingdom plantae.

Some taxonomists  found this system is unworkable because , many unicellular organisms like Euglena have both plantae and animalia.

So these are in separate kingdom for such organisms.

THREE-KINGDOM:

In 1866, ERNST HACKEL solved the first objection and proposed a third kingdom.

But this is not clear the difference b/w prokaryotes and eukaryotes.

Some biologists disagreed about the position of fungi in plantae.

Fungi resemble plants in many ways but ar not autotrophs. They are special form of heterotrophs  that Get their food by obsorption.

FIVE-KINGDOM:

In 1937 , E-chatton   suggested the two terms “procariotique” and “Eucariotique”

Procariotique:

To describe bacteria

Eucariotique:

To describe animal and plant cells .

In 1967 , ROBERT WHITTAKER  solved the problem and introduced the five-kingdom classification system .

This  system is Based on ;

1.       The level of cellular organization i.e. Prokaryotic, unicellular eukaryotic and multicellular eukaryotic

2.       The principal modes of nutrition i.e. photosynthesis, absorption , and  ingestion

On this basis , organisms are classified into five kingdom classification of Whittaker

They  considered genetics along with cellular organization  and mode of nutrition in classification .  They classified the organisms into same five kingdoms as proposed by Wittaker.

 THE FIVE KINGDOMS :

1.   Kingdom monera:

It includes prokaryotic organisms.

Monerans are unicellular , although some types from chains, clusters , or colonies of cells. Prokaryotic cells are radically different from eukaryotic cells . Most are heterotrophic.

2.   KINGDOM PROTISTA:

It includes eukaryotic unicellular and simple multicellular organisms .

. Algae are cellular , colonial or simple muticellular . They resemble plant cells with cell walls and chlorophyll in chloroplasts.

Simple multicellular means that they do not have multicellular sex organs and do not form embryos during their life cycles.

. Protozoans resemble animals whose cells lack  chlorophyll and cell walls.

. Some protists are Fungi-like.

3.Kingdom Fungi :

It includes eukaryotic muticellular heterotrophs which are absorptive in their nutritional mode e.g Mushrooms.

They live on organic material

4.kingdom Plantae:

It includes  eukaryotic muticellular autotrophs. Plants are autotrophic in nutritional mode , making their own food by photosynthesis .

5.KINGDOM ANIMALIA:

It includes enkaryotic multicellular consumers .

 Animalia live mostly by ingesting food and digestive  it within specialized cavities . They lack cell wall  and show movements.