1. Bacteria: These are single-celled organisms that can be found in various environments. They have diverse shapes and sizes and can be beneficial or harmful to humans.
2. Archaea: Similar to bacteria, archaea are also single-celled organisms. They are known for their ability to survive in extreme environments such as hot springs, deep-sea hydrothermal vents, and salt lakes.
3. Fungi: Fungi are eukaryotic organisms that include molds, yeasts, and mushrooms. They obtain nutrients by decomposing organic matter and can be both beneficial (e.g., in food production) and harmful (e.g., causing infections).
4. Protozoa: Protozoa are single-celled eukaryotic organisms that are typically found in water environments. They can be free-living or parasitic and play important roles in nutrient cycling and as food sources for other organisms.
5. Algae: Algae are photosynthetic microorganisms that can be found in aquatic environments. They are diverse in size and shape and can range from single-celled to multicellular organisms. Algae are important for oxygen production and serve as a food source for many aquatic organisms.
6. Viruses: Viruses are non-living particles that require a host cell to replicate. They consist of genetic material (DNA or RNA) enclosed in a protein coat. Viruses can cause various diseases in humans, animals, and plants.
These major groups of microorganisms play crucial roles in various ecological processes, human health, and industrial applications.