2. Unicellular organisms

The organisation of life starts from the atom and extends to the biosphere. In the middle, we have several stages, which filled with both living and non-living things. Here, the basic fundamental unit of life is a cell. They are microscopic, and they carry all the essential functions in living organisms.

They are microscopic, and cannot be seen with the naked eye. They are mostly aquatic, primitive and simplest of all the animals. These organisms perform physiological activities by structures present inside the body of the organisms called the organelles.

 

Unicellular organism that is mostly present in ponds, aslow-moving river , and lakes. It does not have any definite shape. It performs all the activities like digestion, respiration, locomotion and reproduction.

The cytoplasm can be seen as \(2\) layers – the outer ectoplasm and the inner endoplasm. The cell membrane is double-layered, and the amoeba has a nucleus and nucleolus.

 

It is also a unicellular organism that is lives in aquatic habitats. It is typically a slipper-shaped or oblong organism that is covered with hairy structures called the cilia. Paramecium locomotes with the help of these short hair-like structures called cilia.

 

 

Euglena is photosynthetic unicellular organisms that are present in freshwater and saltwater. They have both animal and plant characteristics.

 

Euglena moves using a flagellum which is a whip-like tail. Euglena produces food through the process of photosynthesis through the organelle chloroplast.