Euglena. Euglena are often classified as their own phylum because they exhibit both the characteristics of protozoa and algae. Euglena move making them like protozoans. Euglena contain chloroplasts which allow them to carry out photosynthesis, making them more like algae, although they do not contain a cell wall. That is why euglena can be classified as either as algae or a protozoan.

Euglena sense light by using the eyespot. Since the euglena is like algae, it goes through the process of photosynthesis. The eyespot is typically red and is found near the ‘head’ where the flagellum is found. The euglena uses the eyespot to help find food, at times, when no light is present, the euglena captures and feeds like an amoeba.

As has already been stated euglena move mainly through the use of flagellum. During active locomotion it is swung backward, and waves pass rapidly from its base to its tip. However, the euglena cell is also surrounded the pellicle. The flexibility of the pellicle allows the euglena to crawl through mud or water that is littered with debris. The euglena may also move like a worm drawing up its rear half and sliding forward, this is not the usual method of movement.

Euglena is a single-celled microorganism that has both animal and plant characteristics. Like many plant cells they have bright green chloroplasts that contain chlorophyll and carry on photosynthesis. Like animal cells, they have a long whip like flagellum used for locomotion. The body is typically elongated and somewhat spindle-shaped. It is enclose by a flexible, striated pellicle made chiefly of protein. The front end of the body forms a flask-shaped cavity, or reservoir. A red eyespot, or stigma, is located near one wall of the reservoir at about the same level as a swelling on the flagellum. These two structures are responsible for light sensitivity and enable individuals to become oriented toward light. In addition to the numerous chloroplasts, there are reserves of carbohydrate in the cell. A large nucleus is located in the posterior half of the body.

Reproduction is asexual, in which the body cleaves longitudinally while the nucleus undergoes splitting. This is the same way in which the amoeba reproduces.

Euglena is a common inhabit of freshwater ponds and streams, where it forms part of the plankton living in the upper layers within the range of sunlight. A combination of sunlight, warm temperatures, and polluted conditions often promotes their growth so that they form an opaque green scum on the water’s surface.

The euglena breathes and removes in the same manner as the amoeba. The cell membrane recognizes the nutrients and keeps them from leaving while at the same time allows waste material to leave. Breathing is done in the same manner; oxygen moves in through the cell membrane and carbon dioxide leaves.