Euglena

Euglenas (Singular: Euglena) are unicellular organisms that belong to the class Euglenoidea in the phylum Euglenozoa.

Euglena have the characteristics of both a plant and an animal.

The eyespot of a Euglena is a primitive organelle that filters sunlight into the photo-sensitive structures present at the base of the flagellum. It allows only certain wavelengths of light to hit the structures.The photo-sensitive structures then detect the light that is transmitted through the eyespot and enable the Euglena to accordingly adjust its position to enhance photosynthesis.

It forms a protective wall around itself and lies inactive as a spore until environmental conditions improve. Euglena lacks cell walls. Instead it possesses a pellicle made of protein.