Diversity In Living Organisms

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The variety of living beings found in the geographical area is called biodiversity of that area. Amazon rainforests are the largest biodiversity hotspot in the world. Need for Classification: Classification is necessary for the easier study of living beings. Without proper classification, it would be impossible to study millions of organisms which exist on this earth.

Aristotle classified living beings on the basis of their habitat.

organisms can be divided into two groups, viz. prokaryotes and eukaryotes.

Prokaryotes: When the nucleus is not organized, i.e. nuclear materials are not membrane bound; the organism is called prokaryote.

Eukaryotes: When the nucleus is organized, i.e. nuclear materials are membrane-bound; the organism is called eukaryote.

An organism can be composed of a single cell or many cells. An organism with a single cell is called a unicellular organism. For example, Protista, Amoeba etc

On the other hand, an organism with more than one cell is called a multicellular organism. For example, Animal, Human, etc.

Mode of Nutrition: On this basis, organisms can be divided into two broad groups, i.e. autotrophs and heterotrophs. An autotroph makes its own food, while a heterotroph depends on other organisms for food.

Level of Organisation: Even in case of multicellular organisms, there can be different levels of the organization. When a cell is responsible for all the life processes, it is called cellular level or organization. When some cells group together to perform a specific function, it is called tissue level of organization. When tissues group together to form some organs, it is called organ level of organization. Similarly, organ system level of organization is seen in complex organisms.