Euglenas are unique unicellular or single-celled organisms with both plant and animal features. Typified as a member of the protozoan order, Euglenida is classified as a member of the algal division, Euglenophyta.
Euglenas possess elongated cell with one nucleus that contains pigmented chloroplasts which helps in photosynthesis, a contractile vacuole for excretion, an eyespot to spot sunlight and flagella for movement. Certain species of Euglena may appear red under sunlight, which is primarily because of the presence of large amount of carotenoid pigment.
Euglenas are asexual, that is, they multiply through cell division. Euglena lives in fresh and brackish water rich in organic matter and often appears as green or red ‘blooms’ in ponds or lakes. Several species produce breathing vesicles that can resist drying. Euglenas ingest food into the gullet and basically serve as a food source for fish and other marine critters
--One of the most interesting facts about euglena is its eyespot, which is actually a pigmented organelle found in the anterior and is highly sensitive towards light. This eyespot helps it to detect sunlight for photosynthesis.
--Euglena is both autotrophic as well as heterotrophic. To put it in layman’s words, euglena can produce its own food as well as feed on the food produced by nature.
--Euglena has a oval shaped structure with a round anterior and tapered posterior. The outer part of the cell membrane consist of a stiff pelicle which enable it to maintain its shape.
--The cell of Euglena has a number of organelles to carry out various functions for the organism. The central part of the cell is occupied by the nucleus which is purple in color. It carries the DNA of the cell and carry out several vital cellular activities. Then there are the nucleolus present inside the nucleus which can be identified with its pink color. The inner part of the cell is filled up with a light yellow colored viscous fluid known as cytoplasm.