The Diversity Of Living Organisms
The Diversity Of Living Organisms: Many types of creatures live on this earth. If one tries to study them one by one, then only one life of a person will reduce. Therefore, it has been found convenient to study the organisms by dividing them into several groups. Hence the need for the classification of organisms.
Classification of organisms makes it easier for us to study them. Classification also helps us to diagnose diseases and their treatment.
Basis of Classification:
- Organisms are divides into two classes bases on the presence or absence of membrane-bound organelles: prokaryotes and eukaryotes.
- Those Organisms whose cells do not have a distinct nucleus and membrane-bound organelles calls prokaryotes.
- Organisms whose cells have a distinct nucleus and membrane-bound organelles calls eukaryotes.
- Some organisms that are compose of a single cell are unicellular organisms.
- Organisms that are made up of more than one cell are multicellular organisms.
- Animals also divide on the basis of the level of organization.
- Some Organisms that make their own food are autotrophs and those that get food from other organisms are heterotrophs.
- Organisms that have a simple structure believe to have originates long ago.
- Organisms that have complex structures believe to have originated later. Due to evolution, the complexity of organisms increases.
Many scientists try to divide organisms into different classes, but Robert Whitaker (1969) divided organisms into five kingdoms and today Robert Whitaker’s five-kingdom group is considering the most valid classification. The five groups name by Robert Whitaker is Monera, Protista, Fungi, Plantae, and Animalia.
The following are the main features of Whitaker’s Five Kingdoms:
Monera: These organisms are prokaryotes. Some organisms are autotrophs and some organisms are heterotrophs. The cell wall is found in some organisms. Examples: bacteria, blue-green algae (cyanobacteria), mycoplasma, etc.
Protista: These are eukaryotes and unicellular organisms, they do not have a cell wall. Structures call cilia and flagella are found for movement. They are autotrophs or heterotrophs. Example: Amoeba, Diatom, Plasmodium, etc.
Fungi: These are eukaryotes having a cell wall. And some organisms can be unicellular. They are both host and dead living. Some fungi are also parasitic. Example: Mushroom, Yeast, Penicillium, etc.
Plantae: These are multicellular organisms, in which a cell wall is present. These organisms have foliage, with the help of which they make their food by photosynthesis. Plants have a place in this world.
Animalia: These are multicellular organisms, in which cell walls and foliage are absent. They are hosts. All the animals have been places in this world.
(Some fungi live in symbiosis with blue-green algae. The structure thus form calls lichen).