A unicellular organism is an organism that consists of a single cell. This means all life processes, such as reproduction, feeding, digestion, and excretion, occur in one cell. Amoebas, bacteria, and plankton are just some types of unicellular organisms. They are typically microscopic and cannot be seen with the naked eye.
Functions of Unicellular Organisms
Cells are called the building blocks of life because they often come together to form multicellular organisms, such as plants or animals. However, some organisms consist of only one cell. These are called unicellular organisms. Although much smaller, unicellular organisms can perform some of the same complex activities as multicellular organisms.
Many unicellular organisms live in extreme environments, such as hot springs, thermal ocean vents, polar ice, and frozen tundra. These unicellular organisms are called extremophiles. Extremophiles are resistant to extremes of temperature or pH, and are specially adapted to live in places where multicellular organisms cannot survive. This unique feature allows scientists to use unicellular organisms in ways previously only imagined. When Thermus aquaticus was discovered in the boiling water of a Yellowstone Park hot spring, scientists used its special enzyme TAQ polymerase to replicate DNA billions of times in the span of just a few hours. Without this discovery, forensic science and genetic testing as we know them wouldn’t exist. Other extremophiles have been used for treating arthritis and autoimmune diseases, making paper, treating waste, and radiation resistance.