LIVING WORLD

Why is  need of classification of organisms?

All the living organism on earth have adapted according to geographic regions, food ingestion, defence etc. While adapting, many differences are observed in the organisms of same species too. According to 2011 census, around 87 million species of living organisms are found on the earth- including land and sea. To study such a vast number, it was essential to divide them into groups. So groups and subgroups were created considering the similarities and differences among the living organisms. This process of dividing living organism into groups and subgroups is called Biologica classification.

For classification Whittaker considered following criteria:

 1. Complexity of cell structure : Prokaryotic and Eukaryotic.

 2. Complexity of organisms : Unicellular or Multicellular.

 3. Mode of nutrition : Plants - AutotrophicPhotosynthetic Fungi- Saprophytic- Absorption from dead organisms. Animals- Heterotrophic and ingestive.

 4. Life style : Plants - Producers Animals - Consumers Fungi - Decomposers

 5. Phylogenetic relationship : Prokaryotic to Eukaryotic, unicellular to multicellu

(Robert Harding Whittaker (1920-1980) was an American Ecologist. In 1969 he divided living organisms into 5 groups.)

On the basis of this chart all living organisms are classified.

Let learn about each kingdom one by one.

MONERA:

All type of bacteria and blue green algae are included in the kingdom Monera.
 Characteristics :
 1. All the organisms are unicellular.
 2. They may be autotrophic or heterotrophic.
 3. These are prokaryotic cells without distinct nucleus or cell organelles

Eg.VIBRO CHOLERI

PROTISTA:

Protista  are single celled organisms with well defined nucleus enclosed in a nuclear membrane.They have pseudopodia or hair like cilia or whip like flagella for locomotion. 

Autotrophs- eg. Euglena, Volvox contain chloroplast. 

Heterotrophs- eg. Amoeba, Paramoecium

Eg:

FUNGI:

Fungi are non-green, eukaryotic, heterotrophic organisms. Most of them are saprotrophs. They feed upon decaying organic matter.Their cell wall is made up of tough and complex sugar called ‘Chitin’.  Some fungi are thread like and many nuclei are present in the cytoplasm.

 Ex:

Mushroom

 PLANTE:

Plants are one of six big groups (kingdoms) of living things. They are autotrophic eukaryotes, which means they have complex cells, and make their own food. Usually they cannot move (not counting growth). Plants include familiar types such as trees, herbs, bushes, grasses, vines, ferns, mosses, and green algae.

Eg:

Banyan tree 

ANIMALS:

Animals range in length from 8.5 micrometres (0.00033 in) to 33.6 metres (110 ft). They have complex interactions with each other and their environments, forming intricate food webs. The kingdom Animalia includes humans but in colloquial use the term animal often refers only to non-human animals.

Eg:

Tiger