Microorganisms

• Microorganisms: living organisms that are so small they cannot be seen with the naked eye
• Most abundant organisms, found in huge numbers in any environment
• Are Microorganisms harmful or not?

  Most are harmless to plants and animals

  Some cause disease-pathogens
• Pathogens: microorganisms that cause disease
• Most pathogens are parasites and live in/on other organisms
• All viruses and some bacteria, protists and fungi are pathogenic in nature
• Infectious disease: disease caused by a microorganism
• Unicellular: an organism consisting of only one cell
• Multicellular: on organism made up of many cells
• biodiversity: the variety of organisms found in an area on earth